YZRandomE

BMW E90 Dash Cam Hardwire

2019-02-03T15:25:00.000-05:00

BMW E90 Dashcam Hardwire

My goal here was to have a dash cam setup for driving and parking with wires completely concealed for a fully integrated appearance. My original thought was to use a single Vantrue N2 Pro dash cam with one camera facing rear and one facing front. I planned to mount it on the rear interior lighting module but the front mirror blocks a good view of the road from that angle so I ended up purchasing an additional VIofo A119V2 for the front camera and just used the Vantrue as a rear/interior cam.

ViseeO Tune2air WMA1000

2015-03-15T19:12:00.003-04:00

I finally discovered a better solution than my DIY version for bluetooth music streaming to my 2008 BMW 328xi. The ViseeO Tune2air WMA1000 just plugs into the little 30pin iPod integration cable in my glovebox and pairs up to any smartphone. At $85 it's pricey but provides an elegant solution to an annoying problem of mine.

Sound quality is excellent and it fits perfectly into that little section of the glovebox that holds an LED flashlight. No more having to deal with turning the volume up/down when switching between Radio and Aux inputs!

Just plug it in and pair it up!

As I am streaming from an Android device I don't get any track data or
steering wheel track control functionality unfortunately.

Behind Sofa Wall Shelf /w Outlets

2014-11-22T20:20:00.000-05:00

Here's a random idea for something handy to put behind your couch rather than a sofa table.

Behind Sofa Wall Shelf

This shelf was created for me by Intrigue Custom Creations of Scottsdale, AZ: http://www.custommade.com/by/intrigue/

4/4 solid red oak was stained /w Minwax 215 and then topcoated /w semi-gloss Arm-R-Seal. Overall dimensions of the shelf are 120" L x 14" W

Project Drawing: https://1drv.ms/b/s!AkDiurnLC4Frh6wEO0LJH7Jvu8V5TA

Custom Battlestation Computer Desk Design

2014-06-09T02:35:00.000-04:00

This is a design that I previously submitted on Imgur / Reddit.

Yangorang's Custom Battlestation Desk & Mancave

As with most of my custom stuff this was the result of my annoyance with existing products on the market. I wanted a much larger desk than most as I like to put a lot of stuff on it, and I wanted a keyboard tray wide enough to accommodate my CAD mouse and a super large mouse pad. While I was at it I stuck in some integrated cord management and a little shelf for my active studio monitor speakers.

The most commonly suggested addition to the design on Reddit/Imgur was a cupholder, but I decided against this since I didn't feel it would fit into the overall minimalistic and clean theme of the design. Clearly this desk wouldn't suit everyone, but at the end of the day it's a custom design by me for myself and it embodies everything that I value in a desk for my usage scenario.

Project Summary: https://1drv.ms/b/s!AkDiurnLC4Frh6wKEfHdKSvUApzdhA
DWF CAD File: https://1drv.ms/u/s!AkDiurnLC4Frh6wLI9yiaFw_aNecUA

Feel free to request the latest CAD files from me directly via email. The CAD files are native to Autodesk Inventor but I can export them to a few other formats if needed. The design is freely available to anyone who wants it.

The desk was constructed for me by Intrigue Custom Creations of Scottsdale, AZ: http://www.custommade.com/by/intrigue/

Darker than Black Hei's Dagger Replica Project

2013-07-08T12:38:00.002-04:00

Darker than Black Hei's Dagger Replica Metal Ver Rev2.5

Thingiverse: You can download the STL from here to get the prop version printed - note that you will need to sand and paint the part yourself which takes some skill.

Project Overview
Not to be satisfied with other creations I've seen online, I set out to model Hei's dagger from Darker than Black with CAD so that I could have it accurately fabricated for me and easily reproducible.

Here's a rendering of the model I made - I used various screenshots and scans from the series as reference to make it look as authentic as possible. The layouts that Volphin provides on his website were also a big help, though I did not follow them exactly and you can see the profile in my rendering is a bit different.

I am making a prop version that would be safe for bringing to events as well as a battle-ready metal version that Hei himself could use. I've made the prop version an open design and anyone who wants it can download the model in .stl format at my Thingiverse. If you want it in another CAD format shoot me an email and I can export it for you.

The metal version I made more or less exclusively for myself and a few friends. I'm sure a lot of people would love to have one but few want to pay $500+ to have them custom made.

Please post any thoughts you have in the comments below!

Metal Version Rev.1
I commissioned Burdett Metalsmithing & Design to fabricate a battle-ready replica of this dagger with a 1095 high carbon steel blade and 6061 aluminum handle. The dagger is fairly well balanced with a balance point within 1" of the guard.

As depicted here the metal version consists of three pieces held together by cleverly hidden flush rivets rather than being made of a single piece like the prop version.

The outer profile of the blade is first water jet cut from a sheet of 1095 carbon steel based on my provided CAD files and the bladesmith does his work to take care of the rest. A similar approach is taken with the two handle halves.

The fabrication process for the metal version is quite involved and Burdett has provided me with step-by-step pictures of the process so we can see how it's done. I have these posted below:

Darker than Black Hei Dagger - Metal Version Rev.1

Video Overview: http://youtu.be/9OgEA-62LFc

I think that overall everything turned out fairly well. A better job could've been done with the powder coat masking as it looks a little bit sloppy around the transition from the blade to guard/handle; there is a slight bit of warping right around the tip of the blade as well due to the hardening process. I also mis-estimated the scaling on this first run so the overall length is a whopping 20".

Metal Version Rev.2

I worked with QB Precision Technology Ltd. to create a Rev.2 part. The handle halves are CNC milled out of 6061 Aluminum and anodized black; the blade is CNC milled out of 440C stainless steel and then hardened and sharpened. Overall length is 16" and the assembly is glued together with strong metal glue. This is obviously not as secure as using rivets, but this way you don't have to worry about hiding rivets and masking powder coating. Overall weight is almost exactly 1 pound and it feels fairly hefty in hand.

I was pretty happy with the prototype unit and there are only a few minor issues which I would tell them to deal with if I ever decide to make a batch run. I've posted plenty of pictures in the gallery below:

Darker than Black Hei's Dagger Replica Metal Ver Rev.2

Video Overview: http://youtu.be/VQf9u-QfsY0

Prop Version
I looked into various fabrication techniques to see what yields the best results at a reasonable price for this version. The prop version can either be made of a single piece or out of a three-piece assembly like the metal version. The single piece is more economical but ends up being a bit harder to paint since masking various parts of it is fairly tricky.

The latest .STL file is always available for download at Thingiverse and you are free to do with it as you please. Listed below are some of the fabrication techniques that I have or am currently looking into for this project:

Polyamide/Nylon 12 3D Printing [Selective Laser Sintering]
-Excellent durability; good flexibility prevents it from snapping under stress
-Rough surface requires heavy sanding and primer before painting
-Visible build layering effect throughout part
-Long and thin parts such as this one can potentially end up slightly warped
-One of the cheapest 3D printing materials

Video Overview: http://youtu.be/UwZr99qxrCU

Polyamide is not as premium feeling as paintable resin and has a sandy/porous surface texture due to the laser sintering process but it's easier to post-finish and paint than 3D printed ABS. It's durability and flexibility is comparable to that of paintable resin, and its pricing is fairly reasonable.

The full scale 3D print from Shapeways that I received looks fairly good but has a few visible defects on one side of the part. (due to removal of support material most likely) The part durability is also very good though the porous surface poses a bit of a problem. Paint applied directly to the part tends to get "bubbly" due to air being trapped in the porous surface. I would recommend using a fairly thick sanded primer layer as a smooth painting surface if you want good painting results. I neglected to do this on my prototype so it doesn't look that great.

Paintable Resin 3D Printing [Stereolithography]
-Excellent surface quality enables painting without much post-finishing
-Fairly rigid but can be snapped fairly easily when bent too much
-Visible build layering effect throughout part
-Too expensive even when produced in batches

Below are images of a 70% scale paintable resin 3D print I ordered from i.materialise along with a 35% scale prime gray 3D print just for kicks.

Video Overview: http://youtu.be/Mjy07LSsJnU

My inexperience and lack of patience when it comes to painting things shows here; most of you guys can probably do a better job than I did. I think the results are fairly good though given my lack of professional equipment and experience.

The properties of paintable resin make it almost perfect for the target application. The surface quality / paintability make it possible to achieve a very good appearance. The generated part is also fairly durable and its slight flexibility helps it withstand some minor abuse. The density and feel of the material is just about right for a prop as well.

Unfortunately it is also far too expensive for the target application, and I also snapped the blade cleanly off of one when playing with it just after unboxing.

Resin Casting
-High part accuracy
-Excellent surface quality
-Mold requires high initial investment (~$600USD) but low price per part afterwards
-Slight shrinkage

This process would yield better surface quality and part accuracy than most 3D printing technologies at a lower unit price. Unfortunately at the moment I'm not really willing to put in the initial investment to make a mold of this part, but it may be something I could consider in the future if there is the demand. (which I'm not seeing)

Here's a picture of the part I would use as the master for mold making. It was CNC milled for me out of ABS plastic by QBPrecision Technology Ltd.

The copies would probably be cast out of something like Smooth-Cast 305 or TASK 3 resin from Smooth-On. Resin casting is commonly used by prop makers so it's a tried and true technique and there are quite a few mold makers that could do the job for me as well.

Wrap-Up
So there you have it - a full project log of everything I've done and all of my findings undertaking this project. I'm more or less done with it at this point as I'm happy with my current metal dagger and have already sold all of my 3D printed prototypes on eBay. I'm pretty happy with what I've done and I don't really plan to do anything else with this project. Thanks for reading!

HTC One Car Dock from ProClip

2013-07-03T11:59:00.000-04:00

I was looking for a good car dock for my new HTC One to use in my 2008 BMW 328xi (E90) and came across the ProClip website: https://www.proclipusa.com

You choose a mounting base that is custom designed for your car, in my case part number 853598. This guy clips right on top of the AC vent and is incredibly easy to install. Whether or not it'll be easy to remove in the future is another question but I won't need to worry about that for a while.

Another customized holder for your phone screws onto the mounting base, in my case 511524 for the HTC One. (note that you can also choose options with integrated charging)

Once you have everything installed it looks like this:

The grand total for both of these parts was $78.63 shipped which is quite pricey but at least in the future if you get a new phone you only need to buy the phone holder part. The plastic used is extremely solid (feels like polyamide) and the phone is held very well while driving. The mounting location is also almost perfect for me as it's easily within arms reach but doesn't block any of my view through the windshield or any of the buttons on the dashboard.

The only issue that I've found is that it can cause a little bit of dashboard creak since it kind of pries the bottom portion of the trim slightly outward, so if you're one of those people who can't stand any creak in their BMW you'd best steer clear.

Overall this is a great product and I highly recommend it to anyone looking for a nice phone car dock. They have all sorts of solutions for nearly everybody so take a look at their website.

ODAC Output Switcher

2013-04-11T03:21:00.001-04:00

ODAC Output Switcher

I wanted to use my ODAC as my central PC audio device so I needed it to be able to output to either 3.5mm (to headphone amplifier) or RCA jacks (to active monitor speakers), but I didn't want it outputting to both at the same time to prevent unnecessary loading. I ended up implementing a tiny little board that simply routes the audio signals through a 3PDT switch to either output jack. You can see what it looks like in the image gallery above. It doesn't exactly look elegant as I more or less just glued the board to the top of the ODAC case, but it gets the job done.

DIY OVC3860 Bluetooth Receiver / PKB-PCBA Evaluation Board

2013-04-08T14:05:00.000-04:00

Introduction
Continuing on my quest to get good audio from my phone to my car's aux in I started playing around with bluetooth receiver modules. The ElectroDragon PKB-PCBA caught my eye as a fairly easy to implement solution that offers potentially good quality for the price. It uses the OVC3860 IC which I've heard good things about and also features a SGM4917 headphone amplifier IC which appears to be a fairly handy part with both integrated click/pop suppression and charge pump circuitry to generate it's own negative rail for producing a ground referenced output. Many of the other similar boards I've seen use a basic opamp with a single supply and bulky capacitors at the output to get rid of the resulting DC offset. I believe this is the main reason for their poor performance.

As with all of these Chinese made modules English documentation is sparse at best for the PKB-PCBA and ElectroDragon support was utterly useless as well when I tried to ask for more specifications. Fortunately whoever designed the board had easy implementation as a goal and pretty much all you need to do to use this thing is just feed it power and get your audio output from it. I don't know the exact schematic of the board but it probably looks similar to this application circuit for the BLK-MD-SPK-B which looks fairly solid to me.

If I wanted a more audiophile grade solution I could try to lay my own PCB using a Roving Networks / Microchip RN52 Bluetooth Audio Module with a TPA6138A2 from TI driving the output, but I don't have the equipment or experience needed to take measurements for optimizing the layout/performance of such a design and it's really just too much work for me. My approach of using a highly integrated module saves a lot of time and still yield respectable performance.

Note that I tried the Griffin Technologies BlueTrip Aux (it is one of few commercial products low profile enough to plug-in inside my car's center compartment) before pursuing a DIY solution and found that the BlueTrip outputs a low volume signal with completely non-existent bass. My music simply sounded so terrible that I returned the BlueTrip immediately after testing it. The funny thing is that I was contacted by another BMW owner about my Amazon review who had the same issue with the BlueTrip so I know it isn't just me.

Preliminary Testing
I did some basic bench testing with the breakout board I made below before moving onto the full design.

I found it to draw about 80mA of current total when driving a 32Ω pair of headphones at listening volumes and was not able to measure any DC offset at the output with my equipment. Output voltage level hovered around 0.7Vrms at max volume which is pretty good. The sound quality seemed fairly good through my headphones - there was an audible noise floor but I think this was due to my testing power supply being tied to earth ground. We'll see how it fares in the car on the full design.

Design Overview
As mentioned previously all you really need to do to implement the PKB-PCBA is feed it stable power and give it a jack for output. The 4.7uF output capacitors on the ElectroDragon wiki application circuit are almost definitely not necessary as I did not see any harmful DC offset at the output.

My main concern regarding sound quality would be the possibility of ground loop noise within the car, as the ground throughout this circuit is tied to both the car power ground and stereo ground. If this becomes a huge issue, I may need to use a ground loop noise suppression cable at the output or implement an isolated DC-DC converter for power like I did previously to power a CMOY.

EAGLE Project Folder

An LM2937ES-5.0 IC from Texas Instruments takes in the nominal 12V directly from the car's cigarette lighter jack and provides the 5V power that the PKB-PCBA needs. This is a fixed 5V LDO regulator in a TO-263 form factor which uses the PCB as a heatsink. The LM2937 is "ideally suited for automotive applications" according to the TI datasheet and will "protect itself and any load circuitry from reverse battery connections, two-battery jumps and up to +60V/−50V load dump transients." A 10uF ceramic cap bypasses the input of this regulator and a 220uF low ESR electrolytic cap and 1uF ceramic cap keep the ESR at the output of the regulator within the stable region.

You can see I've also put in a DC power jack for the 12V from the car and a little slide power switch for turning off the unit when it's no longer needed.

R5/R10 add some series resistance to the output of the PKB-PCBA to provide short circuit protection; I'm not really sure if they're necessary as most headphone amp ICs should have this integrated, but they don't really harm the performance any since the input impedance of a car stereo is so high.

Parts List

Mouser Part #	Description
PKB-PCBA	Nice little bluetooth receiver module you can buy from ElectroDragon based on the OVC3860 IC. I do not know of a US supplier that stocks these so shipping usually takes a while.
LM2937ES-5.0	5V fixed TO-263 variant of the LM2937 LDO regulator from Texas Instruments
STX-3120-3B	Basic 3-pin stereo jack from Kycon. It's a very cheap part but the 5-pin version is used in the Objective2 so I know the quality is fairly good.
103-12100-EV	Tiny little SPDT slide switch from Mountain Switch that serves as the power switch in this circuit.
RXK221M1EBK-0815P	A 220uF low ESR electrolytic capacitor from Lelon that serves as the power reservoir for the circuit
MF1/4DCT52R8R06F	Metal-film output series resistors- these aren't really necessary but help provide some short circuit protection as I'm not sure if this is integrated into the SGM4917 IC
ETC	All of the other little parts in this circuit I got from Tayda Electronics or somewhere on eBay. -2.1mm ID / 5.5mm OD DC power jack (Tayda A-4118) -1206 X7R SMD Decoupling Caps can be found around on Mouser or Tayda -1KΩ 0805 SMD RLED (seems like a high resistance for a LED resistor but the LED is still pretty bright actually) -Blue or Red 1206 SMD LED - I had some superbright ones laying around from Sky-Macau -For the cigarette lighter plug the Philmore units from Minute Man Electronics are pretty good quality in my opinion

Assembly
Unfortunately I couldn't really find any particular enclosure that this would perfectly fit inside of so I simply made the board perfectly square with holes for standoffs at each corner for screwing it down to some sort of block. The whole board only measures 5 x 5 cm so it can easily fit almost anywhere in the car.

I soldered down the smaller SMD parts first and then did all of the through-hole parts in one pass. I stuck a tiny little heatsink on the ground plane for cooling the LM2937 but it isn't really necessary as I only measured 85mA of current draw from a 12V power source while driving headphones.

Soldering wires to the cigarette lighter plug was pretty tricky for me especially since the wire I'm using is so thick, but I managed to get everything in there.

Fully setup - nice and neat under that center compartment. Notice how there isn't a whole lot of space height-wise in there which is why I used right angle connectors for the power and 3.5mm aux jacks.

Testing
Setup: from Galaxy Nexus 3.5mm and A2DP to 2008 BMW 328xi stock stereo

The overall sound is better than the sub $50 receivers I've tried from Amazon so far - it's still a little muddier than just using the aux input directly but the frequency response is quite good. The bass response in particular is noticeably better with the receiver so my phone likely just doesn't do a good job with this from its 3.5mm out. I don't hear any audible noise floor or ground loop noise; my car may have audio transformers on the aux input to deal with this, but this could potentially be an issue in other vehicles.

One annoying thing I've noticed is that my phone seems to still think it's connected for a while after I've already turned off the car and receiver, so it'll keep "playing" until it finally notices it's been disconnected.

Conclusion
Overall if you want a simple and good quality bluetooth music receiver this is worth a shot if you're an experienced DIYer. The parts involved are fairly cheap and it's a good learning experience as well. The PKB-PCBA performs remarkably well especially given its price point, and I'm sure that a higher end design could do even better. Sadly I haven't seen many particularly good car powered bluetooth receivers on the market besides the TuneLink Auto which is a bit too tall to fit under the center compartment of my car.

I've shown here you can get pretty decent results with only cheapo parts; I'm only disappointed that I could never find a good commercial product to suit my application, as it wasn't even all that difficult to put together a fairly well performing DIY solution.

Mediasonic HFR2-SU3S2 RAID Enclosure Review & Fan Replacement

2013-04-05T23:10:00.000-04:00

Introduction
The Mediasonic HFR2-SU3S2 is a nice little USB3.0/eSATA HW RAID box that's perfect for various storage applications. Personally I use it in RAID5 mode over USB3.0 with 4x SAMSUNG EcoGreen F4 ST2000DL004 2TB hard drives for backup and media storage. It has been working for almost two years now without a single hiccup and even when a hard drive died it proceeded to reconstruct my array with a replacement drive without any problems.

The Mediasonic HFR2-SU3S2 has a reasonable MSRP of $199.99 but can often be found on Newegg with a rebate or promo code (or even both) which brings the price down to around $129.99. This is a great price for a plug and play USB3.0 hardware RAID box.

Manufacturer Page: http://www.mediasonic.ca/product.php?id=1358153144
Newegg Page: http://www.newegg.com/Product/Product.aspx?Item=N82E16816322004

Build Quality, Features, and Service
The enclosure is constructed mainly of metal and feels very heavy and solid with the exception of the front door which doesn't seem to latch too well and feels rather light and flimsy. The indicator lights on the front of the enclosure provide some useful information and are laid out in an intuitive and logical manner. Overall it's a pretty nice looking enclosure and the build quality is much better than you'd expect for the price.

One aspect of the design I don't like is the power brick; the cable for it feels of rather low quality and it's a bit on the short side in my opinion as well. If I put the enclosure on the top of my desk, the power brick will end up hanging off of the ground because of how they've placed it which is rather annoying. I'm also not a big fan of the power connector coming in from the side rather than from the back, but this is a fairly minor complaint. It's would've been better if they integrated the power brick into the enclosure and put the plug in the back much like on the Sans Digital TR4UTBPN.

I use my enclosure in RAID5 mode with 4X SAMSUNG EcoGreen F4 HD204UI 2TB HDDs. (no TLER I believe) The auto USB on-off functionality performs as expected and I haven't seen any disconnect issues like some others report except for one time when I was copying data off of it for 10 hours straight. It randomly powered off during the copy but after I rebooted it I never saw the issue again so I have no idea what happened.

I've shipped this thing across the country three times with hard drives installed - twice in the trunk of my car and once on a domestic plane flight in my checked luggage. (in the original box) After my plane flight I opened up my checked luggage to find the metal HDD retention bracket warped with the drives partially hanging out of the enclosure next to a TSA inspection note. Upon trying to power the enclosure up the red light next to one of my hard drives lit up to indicate it was bad. (needless to say I was not very happy that day) I immediately replaced the dead hard drive and the enclosure completed the rebuild overnight without any hiccups. During this time I was able to access all of my data without any issues, albeit at much reduced speeds.

Mediasonic documentation isn't the best, but the setup is really fairly straightforward and you can get whatever additional help you'll need on the forums. Generally speaking you only need to consult the manual once to set it up at the beginning and you won't need it for anything afterwards. Mediasonic support is generally very fast to respond to questions on their forum or via email. I asked for a replacement fan when mine was getting rumbly and received one within only a few days with no questions asked - all I had to do was email them.

CrystalDiskMark Results (USB3.0)

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The HFR2-SU3S2 isn't exactly a speed demon but it's respectably fast enough for a budget external USB3.0 RAID array. It's fast enough for me to store and run all my Steam games off of it without load screens feeling particularly long, and loading media files off it is fairly snappy as well.

Final Words
I think this is a great product if you need a 4-bay RAID enclosure; it's not only cheaper than most of its alternatives but offers a good set of features and solid build construction to boot. Mediasonic isn't exactly a well known company, but their support has been more helpful and responsive in my experience than that of many larger companies I've had to deal with.

The Sans Digital TR4UTBPN would probably be the closest competitor to the Mediasonic HFR2-SU3S2 and it's worth looking at as well. The TR4UTBPN is from a more reputable company and looks to be quite a bit speedier while costing a little bit more. I am unsure if the Sans enclosure automatically turns on and off with your computer, and this is a feature I use a lot since my RAID array is basically like a secondary drive to the SSD in my desktop.

Replacing the Stock Cooling Fan
The stock fan is a DFC802012H from Young Lin Tech Co. LTD. It's an 80mm fan with 20mm thickness and a hybrid ball/sleeve bearing. It's held in by M2.5 screws that are about 25mm long.

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YLTC DFC802012H Nominal Specs
-Voltage: 12V
-Current: 0.23A
-Speed: 3500rpm
-Airflow: 37.8CFM
-Pressure: 4.24mmH2O
-Noise: 41.33dB[A]

I really don't like this particular fan because it seems to exhibit a faint clicking/rumbling noise and you can feel the vibrations from it quite easily by putting your finger on it. Most people would probably never notice this, but as the rest of the fans in my system are ultra silent fans running at 800rpm it actually ends up being audible for me. If the stock fan were a pain to get to I probably wouldn't have bothered, but fortunately you need only remove four screws in the back and it simply pulls straight out.

As I could not find any good 80mm x 20mm fans in stock at any of the big distributors I chose a slightly thicker Sanyo Denki 9S0812F4011 San Ace Silent Type 80mm x 25mm fan as the replacement. It has fairly similar performance to the stock fan but is much quieter. I was able to order this fan along with a KM80 80mm fan grill from Mouser Electronics.

Sanyo Denki 9S0812F4011 Nominal Specs
-Voltage: 12V
-Current: 0.11A
-Speed: 2800rpm
-Airflow: 32.8CFM
-Pressure: 3.63mmH2O
-Noise: 24dB[A]

As the new fan is thicker I needed longer rentention screws as well, but the longest thing my local Ace Hardware had for M2.5 screws was 20mm. I ended up using 92005A079 M2.5, 30mm L pan head screws from McMaster-Carr with some nylon washers I had laying around to bolt down the new 25mm thick fan and finger guard.

Connector from stock fan soldered onto new one - just match up the wire colors.

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I had use my dremel to make a little slot for the wires to go through in the same spot it normally would on the stock fan, or it ends up crammed between the new fan and the enclosure.

View post on imgur.com

New fan and finger guard installed on the Mediasonic HFR2-SU3S2.

View post on imgur.com

I'm pretty happy with the Sanyo Denki fan for the most part and I can't feel any vibrations from it at all. It exhibits only a faint low frequency hum which can't be heard at all over the spinning hard drives and I trust that the ball bearings will last for as long I live. I keep it running with the enclosure fan setting in auto mode and I've never seen it go above the lowest speed. The new fan seems to move a pretty good amount of air and I'm sure that removing the restrictive stock fan cover helped as well.

Car 12V Cigarette Lighter Receptacle Power Isolator Circuit

2013-02-15T13:57:00.000-05:00

Introduction
An age-old issue of mine was having to jack the volume on my car stereo (2008 BMW 328xi) way up when playing music from my phone (Galaxy Nexus) over the 3.5mm aux connection. I actually tried using a bluetooth receiver from Griffin Technologies to solve this problem but only found that I had to jack the volume up even more and that the whole bass-band disappeared when using it as well.

I found, however, that using my Objective2 headphone amplifier to amplify the aux in would both solve my low volume issue as well as make my music sound better in general. It was clear to me that a basic amplifier typically used for headphones would probably do the job, but I wasn't willing to swap out or recharge batteries every now and then to deal with it. (especially since I'd always accidentally leave the amp on after exiting my car)

The 12V power from a car's cigarette lighter is far from I an ideal power source, and in many vehicles it shares a common ground with everything else in the car. This leads to a lot of common noise and will also end up blowing up amplifiers using a virtual ground scheme such as the cMoy if you try powering them directly off car power. (as the stereo may also share the same common ground)

Project Overview
I ended up making a fairly basic circuit which consists of only 3 ICs. It basically takes in the 12V from your cigarette lighter and produces a regulated, isolated 12V output.

This powers a cMoyBB from JDS Labs which is configured with a gain of approximately 5. Since the cMoyBB board is nice and compact I'm able to cram my circuit in there right next to it.

I'm using pretty much as much heatsinking as possible on the LM2937 as it really does get quite hot. The cMoyBB only draws about 40mA of current even while playing music into headphones but the LM2937 has to deal with almost 300mA coming into it since it's driving the rest of the circuit.

Theory of Operation
The LM2937 IC from Texas Instruments sits right at the "front" of the circuit and takes the nominal 12V in directly from the car's cigarette lighter jack. This is a fixed 5V LDO regulator in a TO-263 form factor which uses the PCB as a heatsink. A more efficient option would've been using a switching power supply such as the TI TL2575HV-05-Q1, but in my case I didn't need to draw a whole lot of current and the LM2937 seemed like an ideal IC which requires very few external components.

The 5V out of this regulator then goes to a CC3-0512SF-E isolated DC-DC converter from TDK-Lambda which can take in anywhere from 4.5V-9V and boost it to 12-15V. (in this case I have it configured for 15V output by shorting the TRIM pin to -VOUT) This series of converters has everything conveniently under a metal hood and requires few external components.

The isolated 15V output from the DC-DC converter then goes to a LM340 linear regulator IC also from Texas Instruments. This is a nicely performing 12V fixed linear regulator also in TO-263 form factor. It provides a super low ripple 12V for the cMoyBB circuitry to do its job.

It might seem somewhat roundabout for me to regulate the 12V from the car down to 5V only to have to boost it back up to 12V again but there a good reason for this. Even though the power out of the cigarette lighter is nominally 12V it can really take on a rather large range of values depending on the circumstances. For example it could be only 5-6V during engine startup or 14.5V while the engine/alternator are running and I couldn't find a DC-DC converter that could live through all of that; however, the LM2937 is "ideally suited for automotive applications" according to the TI datasheet and will "protect itself and any load circuitry from reverse battery connections, two-battery jumps and up to +60V/−50V load dump transients." In other words the LM2937 is an easy way for me to ensure that my circuit and the cMoyBB are protected from any of the extreme transients that could happen in a car.

It might also seem redundant for me to have the DC-DC converter configured for 15V output when I could set it for 12V output and just use that to power the cMoyBB directly but there is good reason for this as well. The CC3-0512SF-E is spec'ed for a maximum ripple & noise of 120mVpp which is far too much for any sort of audio application. The opamp's PSRR would not be nearly enough to prevent that 120mVpp from being very audible in your music, but the LM340 outputs a far more manageable 0.04mVrms of ripple/noise.

Testing
I stress tested this circuit for a few hours driving a constant 100mA load with no issues. I recorded temps on the board as high as 50C at a few locations which is perhaps mildly concerning, but never did the circuit shutdown or output anything beyond 12.05V.

I've briefly field tested this in my 1996 Toyota Camry as well as my 2008 BMW 328xi with no issues. The interesting I noticed was that I would hear clipping when turning the amp's volume knob beyond about 1/2 of the way up in the 328xi and I saw the same issue when I was using a 9V battery as well. I had initially thought that perhaps this was due to the NJM4556 opamp not being able to swing high enough but the same thing occurred with other opamps as well. I've also confirmed this issue when using my Objective2 in high gain mode so it appears that my 328xi just doesn't like seeing over a 1Vrms signal or so at the aux jack.

I really hope BMW has done something about the low aux volume in newer generation models, (though perhaps with bluetooth no one cares about aux in anymore) as it is quite annoying for me to have to dial in the volume every time I switch between radio/aux sources. This is actually not as much of an issue in my old 1996 Toyota Camry at all since the cheap $30 stereo my dad and I installed has a setting for the aux source amplification which let's you match the volume levels up fairly closely.

Purdue Engineering Fountain Model

2012-11-10T01:15:00.000-05:00

Back when I was in high school I was asked by my boss to create a nice gift for a Purdue professor....this is what we came up with. He was generous enough to give me one too!

Objective2 Headphone Amplifier SS Front Panel

2012-10-22T14:36:00.000-04:00

All sold as of 2/20/2013! I could have another batch made if there is enough demand but so far the batch of 20 has not been profitable for me and it doesn't seem like there is much interest. Be happy if you're one of the few people that managed to get one!

Introduction
When I decided to build a batch of five O2 amps with my friends I, like many others, went to JDSLabs to order their aluminum front panels. When I got them, however, I was honestly rather disappointed - it looked all shiny and nice in the pictures on their website but the actual parts I received looked fairly lackluster and were rough around the edges. I wasn't a big fan of their company logo on the front panel of my DIY amp either. I decided to fire up my CAD program and look into getting some nice stainless steel panels custom machined for me...

DIY Audio Forum Thread

This revision features chemically etched lettering and symbols filled with black oil-enamel paint and uses a #4 (brushed) finish rather than 2B. The panel material remains 304 stainless steel and it can be either waterjet, laser cut, or CNC milled depending on my supplier's capabilities.

Overall I think it is much nicer than the panels from either JDSLabs or Head 'n' HiFi though admittedly it's a good deal more expensive to manufacture as well. You can see from the images that my panel is slightly thicker and fits more tightly around everything.

Here are some images of my initial prototype batch of 20 with Kunshan Krell:

Machined Stainless Steel Objective2 O2 Front Panel

For a production batch of 100 I can easily hit a $12 price point. The main problem is that I never wanted to commit the investment for such a large batch since this isn't my full time job and I don't want to potentially end up sitting on a large pile of these.

50->60mm Fan Adapter for ASUS SABERTOOTH P67 Motherboard

2012-06-02T01:52:00.000-04:00

I got a bit annoyed at all of the rumbly 50mm fans I had to keep swapping out on my ASUS SABERTOOTH P67 Motherboard and decided to get a little 50->60mm adapter machined for me so I could use a nice 60mm ball bearing Vantec Stealth fan instead.
I tried multiple different 50mm models from EVERCOOL and Rasurbo but all of them started rumbling within a month or so. The 60mm Vantec Stealth has been going strong for almost a year now and yields slightly higher airflow as well.

I use OnlineMachinist for most of my DIY machining needs - they offer reasonable prices and are easy to work with.

Linear Regulated USB Isolator

2012-04-25T13:20:00.000-04:00

Introduction
This is a pretty short and simple project – as you might be able to guess from the title it’s essentially an adaption of the USB Isolator from Circuits@Home except with the whole switching power supply section cut out and a LM340-5.0 based linear regulator section spliced in there instead. The pin header to switch between low/full speed USB mode is eliminated as well and this version is locked to full speed operation. I've also added in a little power LED to let you know things are working. Full credit goes to Circuits@Home for an overall excellent original design.

I intend for this thing to be used as a sort of isolator dongle for USB DACs and other devices that want cleaner 5V power than typical switching regulators or USB bus power offer. The assembly is kept very low profile with the use of mostly SMD parts.

Parts List
I won’t go into too much detail here as it is a relatively straightforward build for experienced DIYers and I encourage you to go out and find your own parts rather than just copying and pasting the part numbers I've written down below.

Part	Qty	Notes
Analog Devices ADUM4160BRWZ	1	Heart of this board as you can probably guess. You can buy them from Circuits@Home or Digikey.
Texas Instruments LM340S-5.0	1	5V fixed TO-263 form factor VREG. Ground plane of the board serves as a heatsink for this IC. Mouser Part #926-LM340S-5.0/NOPB or 926-LM340SX-5.0/NOPB
1N4001/1N4002 Diode	1	Protection diode for VREG - you can find these guys pretty much anywhere. I have a bunch that I got for cheap from thaishopetc Mouser Part #625-1N4002E-E3/54 should work
24Ω 1% tolerance 1206 SMD Resistor	4	I'm using Vishay CRCW120624R0FKEA from Mouser
1MΩ 1206 SMD Resistor	3	I'm using Vishay CRCW12061M00FKEA parts from Mouser
MLCC 0.1uF X7R 1206 SMD Capacitor	5	Power supply bypass capacitors I'm using Vishay VJ1206Y104KXAMC parts from Mouser
MLCC 0.22uF X7R 1206 SMD Capacitor	1	Required bypass cap for the VREG since it's located far away from the power supply filter caps I'm using Vishay VJ1206Y224KXATW1BC parts from Mouser
MLCC 10uF X7R 1206 SMD Capacitor	2	Optional additional bypass for the VREG; I recommend using at least the 0.1uF and 0.22uF regulator input bypass caps in but the 10uF ones aren't really necessary I'm using Taiyo Yuden TMK316B7106KL-TD parts from Mouser
PWRLED - 1206 SMD LED (optional)	1	Pretty much any 1206 SMD LED will do; I have a bunch laying around from Sky-Electronic Mart Something like Mouser Part #859-LTST-C230TBKT should work. If you don't feel the need for a power indicator you can just leave this out, it'll save you a bit of power I suppose since it does take ~20mA)
RLED - 1206 SMD Resistor (optional)	1	Value depends on the specs of the LED you choose (LED Calculator Link) and how bright you want it to be I'm using 180Ω Vishay CRCW1206180RFKEA parts bought from Mouser with my cheap LEDs from Sky-Macau that have a FV of 2.2V and FC of 20mA.
Wall Wart Adapter (unregulated DC)(center tip positive)	1	I suggest the Triad Magnetics WDU75-800 which can be bought from Mouser. If you decide to browse eBay find something with the following: -isolated from earth ground (i.e. has a transformer inside it) -2.1mm ID / 5.5mm OD plug; center tip positive! -preferably between 7.5V-9V to minimize power dissipation -output current capability 500mA or more
2.1mm/5.5mm DC Power Jack, Right Angle	1	Please buy these from the Circuits@Home to show your support!
USB “A” type connector, right angle through hole PCB mount.	1	Please buy these from the Circuits@Home to show your support!
USB “B” type connector, right angle through hole PCB mount.	1	Please buy these from the Circuits@Home to show your support!

Rev.1 (Prototype)

The above images are of my first revision prototype boards; there have been quite a few changes to the board since then.

I tested this unit for quite some time and it worked fine but got incredibly hot. I never actually ran into thermal shutdown but the whole board and connectors were getting hot to the touch - part of the reason for this heat is because I was using a 12V power supply; the higher the input voltage the more power the linear regulator IC has to dissipate, which is why I recommend a 7.5Vdc wall wart in the parts list. (typical dropout voltage of the LM340 is 2V)

With only a small exposed ground plane as a heatsink, a SOT-223 voltage regulator IC can only dissipate about 1W of power. This means that (Vregin - Vregout)*(Load Current) < 1W. So if you use a 12V adapter to power this thing you would get a maximum load current of only about 150mA which not really enough to drive more power hungry USB devices such as DAC/headphone amp combos.

The TO-263 part in my newer revision boards should be able to comfortably handle 2W of power which would allow for 300mA of continuous current with a 12V adapter and 500mA with a 9V adapter. I've exposed a fairly large portion of the PCB as a heatsink for the regulator IC since we want this thing to stay as cool as possible for long term reliability and load regulation performance.

Rev.2 (Current)
Changes from Rev.1:

-Eliminated pin headers; now locked to full-speed operation

-TO-263 5V regulator and large exposed ground plane area for additional power handling capabilities

Project Materials

Schematic

Board Layout - 1:1 scale pdf; board dimensions 1.95" x 1.5"

EAGLE Project Folder

I used to have a bunch of extra PCBs and parts laying around but I sold them in bulk to another guy who was interested in the project. The PCB is fairly small and doesn't cost too much to have made at OSH Park.

Assembly
Basic assembly procedures are more or less the same as with Circuits@Home’s original design.
Those experienced with soldering should have no issues with the assembly except for potentially with soldering of the main USB isolator chip; I find the ADuM4160 IC is actually large enough for me to simply align with my left hand while soldering it with my right. Be particularly careful of solder bridges between the pins of this IC! All of the SMD resistors and capacitors are 1206 which is fairly large within the SMD realm. I was able to put this whole thing together in about an hour; most people should have no trouble completing this project in under two hours.

0. Bare PCB

1. Solder on the regulator IC and its input capacitors - I'd start with the smaller legs of the VREG IC; it's actually quite difficult to get the tab down as its being heatsinked so effectively by the board. You may need to use higher temps to get the tab soldered down.

2. Solder down some more of the surrounding components in whatever order you'd like. Once you have the pictured components soldered down, you should be able to plug in your DC adapter and see the LED light up. Use a DMM to test for 5V at the output of the regulator. (use the 0.1uF cap pads right below it)

3. Solder down the main isolator IC - be careful of solder bridges here. Start with one corner pin and spend some time getting things lined up correctly.

4. Solder surrounding caps/resistors and finally the USB jacks.

5. Clean with brush and lots of IPA.

6. Verify basic functionality with some sacrificial flash drive of yours. Copy a large .zip file over to it and use 7-zip or similar to check the archive for errors. I saw copy speeds of only ~800KBps so it may take a while.

Maximum Power Considerations

With the ~0.6 sq in exposed ground plan on each side of the board: (Vregin - Vregout)*(Load Current) < 2W for the TO-263 LM340-5.0 VREG

If you stick with the 7.5V adapter that I've recommend in the parts list, then you'll find that things will stay as cool as possible and you should be able to handle pretty much any USB device. A standard PC USB port can supply 500mA of continuous current so you'll be able to match this by using a 7.5V-9V adapter.

-If you only plan to use this USB isolator with fairly low-powered devices (<200mA current) then you should have no thermal issues whatsoever with any power adapter from 7.5V-12V.

-If you are going to be using this isolator with more a power hungry device such as a USB DAC (>300mA) I recommend going all out on the heatsinking as I've done here and sticking to power adapters in the 7.5V-9V range only.

-Do not use this isolator with any USB device that draws more than 500mA of current. I believe this is generally limited to a few devices that quick charge batteries over USB.

The ground plane should keep things cool enough for proper operation as long as your adapter is 7.5V-9V but the regulator IC will still be getting fairly toasty if you're driving heavy duty devices so extra heatsinking never hurts. Just make sure your heatsinks aren't shorting out any circuit elements. The VREG has a maximum junction temp of 125C and features internal thermal shutdown to protect itself so you are unlikely to destroy it even without extra heatsinking, but again it's always better to stay as cool as possible.

I used the following contraption to test the current consumption of several USB devices:

No devices connected: 18mA (idle power of the ADuM4160 and power LED current)

DPScope SE: 70mA

USB Flash Drive: 90mA

Audinst HUD-MX1 (USB power only): 340mA

Galaxy S 4G (charging): 500mA

I've been stress testing my isolator driving the Audinst HUD-MX1 (340mA) with a 7.5V power adapter (measured 9V when driving the Audinst) and only the bottom heatsink as pictured below. (~1.4W dissipated by regulator IC)

After 12 hours of continuous testing the above setup the highest temp I could measure with my IR gun was about 50C which isn't too bad.

When charging my Galaxy S 4G @ 500mA the 7.5V power adapter measured 8V and after several hours I still measured about 50C at highest with my IR gun. I probed around the exposed ground plane and surface of the regulator IC to find the highest temp. (~1.5W dissipated by regulator IC) Output voltage of the regulator IC measures a stable 5.08V under these conditions. (USB spec states you should stay within 4.45V–5.25V)

So far it seems like everything is working fairly reliably even under heavy loads.

Rev.3 (Future)

These are a few possible changes I would consider if I were to pursue a Rev.3:

-addition of miniature slide-action power switch
-remove 1N400x protection diode due to low risk of input short

-integration of ACM3225 common-mode choke as per Analog Devices CN0160
-optimize layout per AD application guides and consider transition to 4-layer PCB

-two holes for mounting 6-32 standoffs

Disclaimer: I won't take any responsibility for things getting blown up or otherwise destroyed. The project is open and should be considered unverified with only limited testing conducted by myself.

Sky-Macau PCB Fabrication Service Review

2012-03-29T18:54:00.000-04:00

I traditionally use DorkBotPDX for all of my DIY PCB fabrication needs, but for larger boards the flat $5 per square inch cost doesn't tend to work in your favor, so I decided to test out the PCB fabrication service that Sky-Macau offers.

Since I was making a few Objective2 headphone amplifiers with my friends I decided to have five of these PCBs made with Sky-Macau. I emailed pcb@sky-macau.com with NwAvGuy's O2 project folder and asked for:
-Desired Quantity: 5
-Layers: 2 (4 and 6 also available)
-Color: Green (blue, red, yellow, black, white available)
-Board Thickness: 1.6mm (free for other thicknesses actually)
-Surface Finish: HASL (ENIG available)
-Manufacturing Time: Normal
-Shipping Service: Standard Airmail

-Default copper weight is 1oz but they do have 2oz capabilities

I received a quote of $58 shipped for five boards which equates to $11.60 per board, and the O2 boards are a good 80mm x 100mm in size. (~12.4 sq in) It is important to note that throughout my communications with the company I always received responses within 24 hours and the responses were always written in fairly good English.

The turnaround time is admittedly quite long unless you pay extra for expedited fabrication and shipping but the value is definitely quite good. I sent my project folder to them on 2/25/2012 and received my boards about a month later on 3/28/2012.

Here's images of the O2 PCB fabricated by Sky-Macau:

It looks about the same as the one I had on hand from JDSLabs if not slightly higher quality. I think the silkscreen is slightly sharper on the Sky-Macau boards than the JDSLabs one.

Using my benchtop DMM as an ohmmeter I checked a few trace resistances and was pleased to find they were more or less the same as the JDSLabs ones. (my DMM has a resolution of 0.01ohms at best)

Overall I think I've found Sky-Macau to be a fairly good place to get cheap PCBs made if you need five or more. DorkBotPDX will still give you better quality boards and faster service, but Sky-Macau offers a reasonable level of quality and features for the price if you're willing to wait.
I still find Seeed's Fusion PCB service hard to beat in terms of cost, but their options are rather limited (1oz only, limited colors, fixed quantities, etc.) and I don't think their quality is as good. I encourage others to give the Sky-Macau PCB fabrication service a try and let others know what you think in the comments below!

Sky-Macau Parts Store
As you may have noticed Sky-Macau also carries a decent selection of cheapo electronic parts, but I find that Tayda Electronics generally has higher quality parts and faster shipping. There are still a few things I get from Sky-Macau though including SMD resistors/capacitors/LEDs and USB receptacles. I actually think their 1206 LEDs are quite nice and I've found that the 0.1uF1206 caps seem to be on target capacitance wise but the 1uF are more like 0.77uF or so and the 10uF are more like 7uF or so. Considering you get 50 of them for 3USD I never expected much anyway.

Linear Regulated Power Supply (Fixed)

2012-03-16T23:54:00.000-04:00

Introduction

This is an easy to assemble, all-in-one linear regulated power supply solution. It utilizes a TO-220 form factor positive fixed linear regulator such as the LM340 or LM78xx series and takes an input voltage of up to 35Vpk from a wall transformer based on the regulator used. The fuse, switch wirepads, and all of the linear power supply circuitry are integrated on one board – it is meant to be used inside of a HAMMOND project enclosure and all it needs is reduced VAC from a wall transformer of your choice to function. DO NOT connect this directly to the line AC from your wall outlet, as you will simply fry pretty much everything on the board with the high voltage!

I think this project will make a good project for beginner hobbyists or those who need a simple but good LRPS. I don't intend to sell it as a kit or fully assembled since this is supposed to be a DIY project after all.

I realize that there are a lot of other LRPS designs out there already but I think this one has its merits or I wouldn’t have bothered putting it up. In fact I’ll list a few alternatives right here for you to check out and compare for yourself:
AnalogMetric LV30 LRPS
NightFire Kit #1772
AMB σ25 Regulated Power Supply

Theory of Operation

A reduced VAC (ex.16VACrms) comes in from your wall transformer to the board. CSH shunts away high frequency line noise and transients. Five fairly large reservoir capacitors come after the full-wave bridge rectifier to provide an excellent unregulated DC signal. A bleeder resistor (R2) is implemented for safety purposes.

CBY bypasses the input to the voltage regulator IC and helps reduce input ripple. The 1N4002 diode is implemented as a protection diode for the regulator IC. Electrolytic, tantalum, and ceramic capacitors (C5, C6, C7) are paralleled at the output of the regulator in order to provide excellent transient performance and low impedance over a large frequency range.

Input/output power and your on/off switch are hooked up by terminal blocks which accept between 26-16AWG. (I recommend you use at minimum 24AWG) I find that these work fairly well and provide an easy means of wiring stuff to the PCB. A fairly large ground plane is implemented in order to reduce noise and minimize stray inductance among other benefits.

Project Resources
Schematic
Board Layout - Board layout is 1:1 scale so you can print it out if you want to get an idea of the dimensions

EAGLE Project Folder

Parts List

Note that I've listed parts for a 15V output, but only slight tweaks need to be made if you want different output voltages for other applications. Many of these parts are incredibly common and you can probably get cheap alternatives for almost everything from a vendor such as Tayda Electronics. You can do quite a lot with the board and I encourage you to come up with your own customizations and parts – this parts list is more or less here just to get your started.

Part	Qty	Mouser Part ##	Description
AC Adapters 120VAC to 16VAC 1.0A	1	553-WAU16-1000	Wall transformer from TRIAD Magnetics that dumbs the AC line voltage down to 16VAC; excellent build quality but rather bulky and expensive
ACIN/DCOUT/SW - Fixed Terminal Blocks 2P LS5.08mm 90DEG	3	651-1729128	Durable little terminal blocks from Phoenix Contact that are used for hooking up wires
DCOUT - DC Power Connector 2.1mm Pwr Plug Red Tip Blk Handle	1	502-762	Very high quality 2.1mm ID / 5.5mm OD DC power connector from Switchcraft - very expensive but I like it a lot
*DCOUT (Alt) - DC Power Plug 2.1mm x 5.5mm x 9.5mm	1	N/A	Cheapo part from Tayda Electronics; 9.5mm length Absurdly cheap and gets the job done
Rubber Grommets (optional)	2	534-740, 534-731	Little grommets you fill holes in your enclosure with to pass wires through; choose your own from the Mouser mounting hardware section
F1 Fuseholder for 5x20mm fuses	1	576-65600001009	The fuseholder for a standard 5x20mm fuse - you could short this and not use a fuse at all but I wouldn't recommend this - I've already blown one myself while testing this thing
F1 Fuseholder Cover (optional)	1	576-66000001009	This is a little cover for the fuse holder if you feel like being neat
F1 5x20mm 0.5A Fast-Acting Fuse	1	576-0217.500MXP	This guy will blow immediately if more than 500mA of current passes through it. The regulator IC can technically handle 1A of current but it is recommended you don't use this power supply for more than about 500mA of continuous current.
SW - any panel mount switch from Mouser or Radio Shack	1	Find your own (needs to be rated for required AC voltage)	Mouser carries a huge selection of switches; Radio Shack has a good selection as well and you can choose one that you think looks cool Since the board is fairly small you should have quite a lot of space inside your enclosure to work with so switch dimensions shouldn't be an issue for the most part
CSH/CBY/C8 - Multilayer Ceramic Capacitors (MLCC) - Leaded 0.22uF 50volts 10% X7R 5mm LS (Vishay)	3	594-K224K20X7RF53H5	These little ceramic capacitors are used for high frequency bypassing throughout the circuit; you could use a NP0/C0G ceramic here if you want as an upgrade; alternatively film caps will work well here too
B1 - Bridge Rectifier 1 Amp 400 Volt DO-41 (Diodes Inc.)	1	621-DF04M	DO-41/DB form factor bridge rectifier (plenty of cheapo alternatives available)
*B1 (Alt) - DB104G Single Phase 1A 400V Glass Passivated Bridge Rectifiers (Taiwan Semi)	1	N/A	Cheaper alternate part available from thaishopetc
RB - Metal Film Resistors - Through Hole 1/4watt 10Kohms 1% (Vishay)	1	71-CMF5510K000FKEK	Bleeder resistor that provides a discharge path for the input reservoir capacitors when the circuit is turned off - this part is included for safety purposes
C1-5 - Aluminum Electrolytic Capacitors - Leaded 35V 1000uF 20% 12.5x20 mm	5	140-REA102M1VBK1320P	Input reservoir capacitors; general purpose part from Lelon 12.5mm diameter / 20mm length / 5mm lead spacing
D1 - 1N4002 Diode Rectifiers Vr/100V Io/1A Glass Passivated (Vishay)	1	625-1N4002GP-E3/54	Standard 1N4002 diode - serves as a protection diode for the VREG
VREG - 15V Standard Fixed Linear Regulator (National Semi)	1	926-LM340T-15/NOPB	You can use more or less any TO-220 fixed output voltage regulator in this spot - the Audinst HUD-MX1 needs 15V so I recommend the 15V edition of the LM340 from National Semi; you can request samples from their site or buy them from Mouser along with everything else
TO-220 VREG Heatsink (required)	1	Find your own	Try to find something that doesn't stick out to the sides or front of the VREG too much or you'll end up running into C6 or CBY I have a bunch from thaishopetc that work quite well and are very cheap
C6 - Aluminum Electrolytic Capacitors - Leaded 25VDC 150uF 6.3x11.2mm LS 5.0mm (Panasonic)	1	667-EEU-FR1E151B	Aluminum electrolytic output capacitor
C7 - Tantalum Capacitors - Solid Leaded 25V 10uF 10% (AVX)	1	581-TAP106K025SCS	Tantalum output capacitor
RLED - Metal Film Resistors - Through Hole 1/4watt 680ohms 2% (Vishay)	1	71-RL07S-G-680	Resistor to set LED operating current which will depend on your desired output voltage and LED - you can easily calculate this with one of the many LED resistor calculators available online [http://ledz.com/?p=zz.led.resistor.calculator] For my 15V power supply and the LED in this parts list this yields about 17mA of current through the LED which I find is decently bright.
LED - Standard LED - Through Hole Blue Round LED	1	941-C503BBCSCV0Z0461	LED from Cree that has a 3.2V typical forward voltage and a desired operating current of around 20mA You can be lazy and just drill a hole through the enclosure for the light to shine through or you can use an actual LED panel mount (Mouser #749-CR-174)
Project Enclosure (HAMMOND)	1	546-1591XXSSBK	The specific project enclosure that this PCB is designed to fit in - measures 4.3L x 3.2W x 1.6H You only use two #4 screws to mount one side of the PCB down onto the enclosure If you want to use another enclosure you can always drill mounting holes of your own into the PCB or just use some sort of adhesive on the backside
*Project Enclosure (Alt)(HAMMOND)	1	546-1591XXTSBK	A possible alternate enclosure if the recommended one is out of stock - measures 4.8L x 3.2W x 2.2H You'll need to redrill two holes to mount the PCB inside this one
PCB Screws for Project Enclosures	1	546-1593ATS50	#4 screws that HAMMOND makes for screwing down PCBs in its enclosures; you could simply go to a local hardware store and buy a couple as well since these are standard screws anyway

Things like heatshrink, wire, and solder I expect you to find by yourself or just have laying around. For solder I usually use Cardas quad or 62/36/2 from RadioShack. Heatshrink and wire I usually just buy in bulk off of eBay or Tayda Electronics.

Assembly

All parts on this board are through-hole and fairly well spaced so that even those new to soldering can assemble this project with relative ease. The design still manages to remain reasonably compact with overall board dimensions of 2.5″L x 2.0625″W. You’ll end up with quite a bit of free space inside the HAMMOND enclosure to work with. My only words of caution are to basically not heat things up too much to avoid component damage, and to watch for solder bridges between the leads of C6, C7, and the VREG pins as these are probably the only things remotely close enough to be accidentally bridged together. Also be mindful of component orientation for the electrolytic capacitors and diodes.

The parts in my recommended parts list are for a 15V power supply – if you need a different output voltage you can use your own parts as necessary. You can pretty much build a power supply for any TO-220 fixed linear regulator that you can find on the market – just make sure you are familiar with the design and know what you are doing before you go around using parts of your own. I won’t take any responsibility for things getting blown up – I just provide the board and what you put on it is your own problem.

Linear Regulated Power Supply

The regulator IC can technically handle 1A of current but it is recommended you don't use this power supply for more than about 500mA of continuous current. Things will get quite hot beyond that and performance will suffer.

Testing
Loading to 150mA of current and AC coupling the output to a 101gain op-amp in non-inverting configuration (then dividing by 101) I measured 0.06mVrms of ripple from my benchtop DMM which is pretty much what I'd expect. Voltage held steady at 12.05V with a 200mA resistive load.

15V Audinst HUD-MX1 Switching PS

-1.6mVrms off of benchtop DMM (Tenma 72-410A)

-1.68mVrms off of DPScope SE (100 averaging)

-5.74mVpp off of DPscope SE
-Switching frequency ~68KHz?

My LRPS

-0.06mVrms off of benchtop DMM

-0.05mVrms off of DPScope SE (smaller than the DPScope SE can accurately measure)

-0.18mVpp off of DPScope SE

Note that these are admittedly fairly basic tests as I lack the high-grade equipment required for anything more detailed than this, but I think that they're still good enough for a basic comparison.

Disclaimer: I won't take any responsibility for things getting blown up and/or injuries received if you decide to pursue this project. The project should be considered unverified with only limited testing conducted by myself.

DPScope SE - Cheapo Oscilloscope for DIYers

2012-03-04T05:16:00.000-05:00

If you need a very basic oscilloscope for DIY use then definitely take a look at the DPScope SE. It sells for under $60USD as an unassembled kit that includes everything you'll need minus the probes and the USB cable.

Bandwidth, sampling rates, and resolution are quite limited but for the price you still still get an excellent set of features including triggering and FFT spectrum analyzer functionality and you won't be able to beat the price for a two-channel oscilloscope / logic analyzer. The software is fairly well done too and I find it very easy to use. ADC sensitivity is around 4mV and there is no AC coupling mode, but you can achieve AC coupling by means of a series capacitor. [Specs page]

The DPScope is also very easy to assemble (if you're reading this I assume you have prior soldering experience anyway) as it utilizes only through-hole parts and excellent documentation is provided. I was able to get it up and running in one go. Assembly time took approximately two hours for me and I'm a pretty slow solderer.

Project page: http://www.pdamusician.com/dpscope/overview_se.html

Most people will probably tell you to get real oscilloscope and I'd have to agree if you want to do serious work, but the DPScope SE definitely performs as advertised and if that's all you need then go for it. I'll probably be buying a Rigol 1052E, Instek GDS-1052-U, or a OWON PDS5022S after I move.

Use TVBR AAC-LC Instead of MP3 for your Music Collection

2012-02-29T01:33:00.000-05:00

MP3 is seriously outdated people…and so is NeroAACenc. There are better options out there now and keeping your audio in AAC-LC format at TVBR127 quality gives you excellent audio quality along with small filesizes.
Lack of encoding utilities for doing this is somewhat of an issue…but you can have foobar2000 and QAAC encoding to AAC TVBR127 fairly quickly and painlessly.
Basic steps:

Download and install QuickTime
Download and extract QAAC
Download and install foobar2000
You can access the foobar2000 converter by right clicking a song or songs within foobar2000 and going to Convert -> …
See screens below; foobar essentially decodes the file you’re converting to a temporary wave file and passes it to QAAC along with the custom commands you put in the “Parameters”
Convert!

I guess you could always keep your whole collection in FLAC as well if you have the space…but I think that TVBR 127 is the new best lossy audio format vs MP3 320KBps that a lot of people still seem to be using.

ThinkPad T420s Review

2011-05-15T13:00:00.000-04:00

A little gallery to go along with it: http://photobucket.com/t420s

My Config

Type: 4170-CTO
Processor: Intel Core i5-2540M Processor (2.6GHz, 3MB L3)
Operating system: Windows 7 Home Premium 64 -> clean installed Windows 7 Ultimate x64 on UEFI
Display type: 14.0 HD+ (1600 x 900) LED Backlit Antiglare Display
System graphics: Integrated Intel HD Graphics 3000
Total memory: 2 GB DDR3 - 1333MHz (1 DIMM) -> Upgraded to 8GB Samsung RAM ordered off Amazon
Pointing device: UltraNav with TrackPoint & TouchPad plus Fingerprint reader
Camera: 720p HD Camera
Hard drive: 250 GB Hard Disk Drive, 5400rpm -> Upgraded to Intel 320 series 160GB SSD
Optical device: DVD Recordable
System expansion slots: Express Card Slot & 4 in 1 Card Reader
Battery: 6 cell Li-Ion Battery - 66+ and ThinkPad Battery 42 (UltraBay Battery III)
Power cord: Country Pack North America with Line cord & 65W AC adapter
Wireless LAN adapters: Intel Centrino Advanced-N 6205 (2x2 AGN)

Awesome Features

Excellent ThinkPad keyboard and TrackPoint as usual, still the best in the industry even though they never really change all that much; I'm a regularTrackPoint user myself and the EliteBook "PointStyk" is just horrendous (same with the DELL & Toshiba pointing sticks)
Relatively good battery life in a lightweight, compact form factor; no need for big, clunky batteries to last through a day (still less battery life than the T420/T520 though sadly even with the bay battery)
Relatively good build quality holds true, along with the classic matte finish which I like a lot; the nice non-slip finish makes it easier to grip than most other laptops
Excellent VOIP call quality with VOIP mode enabled from the audio control panel; good webcam quality as well
Really no crapware at all installed on the stock OS that Lenovo ships out; you actually don't have to do a clean install to have a usable and quick system; ThinkVantage power manager is quite handy as well and I like it a lot
Extremely speedy performance and boot times (using the fingerprint reader security does slow down the boot a bit though - I hope Lenovo works on making this faster)
Being able to swipe your finger to bootup your computer is a nice little feature that I use on a regular basis
InstantResume is quite handy for when I move between locations and I use it quite often
You get a USB3.0 port unlike the rest of the T series...this is sadly one of the major reasons I didn't go for a T420 or T520

Terrible Annoyances

Mediocre viewing angles for the screen as usual...it gets the job done...but I wish they would just stick IPS screens onto all ThinkPads; I could never understand why they think business users don't need decent screens
Found a little bit of flex in the lower right corner of the keyboard, (fixed with a bit of duct tape) as well as around the power/mute button area; there's a little bit of creaking in the lower left corner where the HDD cover is as well (EDIT: now fixed after I sent it in to the service depot)
Some kinks to work out with the fingerprint reader software/driver and UEFI installations of Windows; fingerprint functionality is not as streamlined as HP EliteBook's implementation in my opinion (using it seems to slow down the ThinkPad boot time)
Fan is rather noisy and seems to be spinning up and down all the freakin time - already tried all the different fan settings in TV PowMam - temps are a bit higher than I'd expect as well; I suggest you use TPFC if you want to keep fan noise down; there is a huge thread raging on about this right now at the Lenovo Forums
UltraBay devices seem to be wobbling around inside the UltraBay slot since there is just too much free space in there; this is especially annoying with the optical drive because it is sorta clanking around noisily in that UltraBay when you are reading/burning discs; not sure if this is a design level or manufacturing level issue but I wish it would fit more snugly and seamlessly in there (not fixed at service depot when I complained about it)
Hinge is a bit flappier than I'd like - I wish the screen would hold itself in one position a bit better, as when I set the laptop down sometimes it'll end up falling back a bit
I feel port placement could've been slightly better on the sides - they should've been able to squeeze at least another USB/eSATA combo port in there
Odd bug where screen switches over to 50Hz when you unplug from a power source - does not switch back to 60Hz when you plug back in; probably just a minor software bug (fixed I believe)

Other Notes

Fingerprint reader on T420s is a bit narrower than I'd like, but it also seems to be a bit more responsive than others I've dealt with
Speakers are better quality than they used to be….I think...but I suppose that isn't saying much, as they're still worse than what you'd find on most consumer laptops
Still wish there were HDMI on all ThinkPads, as VGA is becoming seriously outdated and DisplayPort is nowhere - even at work all the projectors have HDMI

Bottom Line

Is the T420s really all of the power of the T420 in a slimmer form factor with no compromises? Pfft no...The T420s is definitely less sturdy, runs hotter, has less ports, and has less battery life/options than its big brother, but if you're enough of a maniac to give all that up to get a laptop that's a good pound lighter and a bit slimmer....then go for it...

HP Business Outlet Review

2011-01-15T13:00:00.000-05:00

HP Business Outlet

As I haven't seen many testimonials out on the internet from people who have ordered from the HP Business Outlet, I thought I'd share my own experience.

The first thing you might notice is that the HP Business Outlet is really just a daily updated list of refurbished computers from HP. One of the issues with this is that the laptops are taken throughout the day and when you call to order you may find the model you want has already been sold. If you are interested in ordering from the outlet try to have a good 2-3 options in mind when calling so you have a good chance of getting one. I was lucky and was able to get my first choice part number though.

The prices they list are very reasonable and when I ordered there was an additional 20% off promotion on all clearance section business computers. As a college student, I had been wanting a nice but reasonably priced business-class laptop for some time and I was able to snag a EliteBook 8440p (Core i5, 2GB RAM, WebCam, 250GB HDD...) for only $658.91 including shipping and taxes. I would consider that to be an extremely good deal considering that those things normally cost well over $1K and at best even the ThinkPad T410 I was also considering would've cost at least 100-200 dollars more.

The orders are done fully through the phone, and hold times could potentially get long at certain times; I waited only about 5 minutes though which isn't bad at all. It is somewhat annoying that you really have to make sure they get every letter of your address and email and all that correctly over the phone, but the HP rep was professional and easy to work with. Naturally he tried to sell me a couple of extra accessories to go with the EliteBook I was ordering but when I said I didn't need them he didn't ask twice.

I placed my order on 11/30/2010 and I received a Fedex tracking number promptly the next day. I received my EliteBook on the morning of 12/3/2010, so I got this thing about as fast as I would get any web order from Newegg or Amazon. Kudos to the HP Business Outlet and Fedex for speedy service.

Now on to the actual laptop…
You can see pictures of exactly what I got here: EliteBook 8440p Photobucket Gallery
The unit I received was more or less in like new condition, except for a small scratch or two on the lid (which probably happened during shipping as they didn't even put the thing in plastic wrap) and the Microsoft sticker peeling off on one edge. I'd say they should've done a bit better of a job with packaging, but other than that my laptop has been working great and I really like it. I won't bother to review the 8440p in particular as there are plenty of those on the web already, but I will say that I really like the brushed metal look and feel, and that it is a very solid laptop overall. I also think that your mouse-input options on the ThinkPad T-series are a bit better, but the EliteBook in my case was a better value and actually has a more solid feel in my opinion.

I would definitely recommend taking a look at the HP Business Outlet to anyone who is looking for a nice machine on a budget; they have an excellent selection at reasonable prices and if something does break you have a 1yr standard HP warranty to cover your back. My experience was quite positive overall and I hope it will be the same for all of you as well. Thanks for reading!