xheavenlyx

Push Pull Door Dilemma: A sticker solution.

2011-01-04T00:17:00.000-08:00

This post got me thinking about those hundred of doors I have opened and closed in my life with the sticker of either "PUSH" or "PULL" even if they could open either by pushing or pulling.

So, for the fun of it this sticker can be used for doors that open both ways.

It takes me at least a second to decide if I should push the door or pull it if I have clearly seen it possible to do so either ways. Some store doors open both ways, where in some places, it's really uncomfortable to follow the sticker blindly and this is where we loose time.

Door swing directions are mildly regulated for safety reasons. For example, a public building or a housing complex should have outward swinging doors. This is so that in case of a fire, people should not huddle together at the exit, trying to swing the door towards themselves! It should open outwards for easy escape.

Home doors should be inward swinging doors. In case of fire, or an emergency it would be easy to barge the door, without the frame coming in the way. The flip side could be an unwanted person easily kicking in the the door if it opened inwards.

Interestingly, toilet doors have always got me thinking. Why do toilet doors swing inward, if their isn't enough space to stand comfortably inside? Some say no one likes to get locked in without being able to be rescued by a kick from the outside, well, that is one reason for the door to swing inward. However, a negative aspect of this system is the comfort of the person who has to 'visit' inside the small space. Recently, I had been to a portable 'restroom' where the only way to use it was to get in through the inward swinging door, stand on the throne, close the door ...did not do any of this, I kept the door open and... In the end it's all about common sense and usability.

A new Q&A section!

2010-09-24T05:46:00.000-07:00

I have edited the Q&A section I introduced a while back to a more, user friendly version. The last one was a Facebook plug-in called Facebook Live Stream, which was mostly useless for our need.

The new system allows you to chat in real time. Basically, it's just for fun, but if someone has a question they can write it down or answer one posted by someone else. It can be a place for engineering students to discuss projects, clear doubts or just relax after a hectic day.

Have fun on Q&A.

Facebook Dislike and Indifferent Buttons

2010-09-18T12:23:00.001-07:00

I to write an article on a dis button, but don't know where to start. I understand that the button does what it's supposed to do; share something you on your Facebook page with all your friends.

Now, what if there is something I do not and want to share that with my friends? Would I need to click on and then specify what my actual feeling are towards the content I dis? Why, in the name of inter-web, can't I get a dis button to make my job easier. Do the people at Facebook not want us to question the ness of something?

Like many before me who have pointed out, I feel there is a need for

or better yet, a what-the-hell button

The Salvage: Pace Dgital Receiver Decoder

2010-09-16T08:33:00.000-07:00

I had an old digital receiver which was lying around useless. You can salvage a lot of electronic parts from this.

Since it is a audio / video device, most of the soldered IC's cannot be used by themselves, and I am not interested to do so. However, there are many other parts you can use.

Details of the Receiver (Set top Box):

PACE
DVR 500 Digital Integrated Receiver Decoder
MODEL NO.: DVR01-G
PART CODE: 540-1601700
220 – 240V AC 50Hz 45W MAXSERIAL NO.: PCDCAKI617442265
Made In U.K.

In this model you can find standalone IC’s for video processing and audio processing, a microcontroller, PCMCIA CARD and a PCMCIA Slot, with other removable parts.

Observation:

1. Lots of IC's. Video processing, Audio processing. At that time our television sits used to display mainly analog AV. These days its digital, hence the small package of your standard set top box. I have lost the list of all the IC's but I remember there used to be atleast 2 microcontrollers.

2. There are lots of parts you can use. For example observe the 3 LED's on the top-left corner of the above image. Just on the right of the LED's are 3 push buttons.

Parts Obtained:

4x RCA female connectors: Good for some home projects. I may document one soon.

1x RS-232 female connector.

3x Green LED's

4x7 LED segment display

IR Detector: Which was used for the remote control.

IR LED (transmitter): From the salvaged remote control.

PCMCIA Slot: Useful for me because I have an ooold Acer Extensa 500 Laptop with a PCMCIA Ethernet card. Now I can use that with this slot for a wireless robotics project.

PCMCIA Slot with a card inserted

That is all for now, keep an eye on The Salvage series for interesting salvages from old devices.
Happy Tinkering!

Older Salvages: The Salvage: Composite to RF Converter

The Salvage: Composite to RF Converter

2010-09-10T02:36:00.000-07:00

This is one the first in the series of The Salvage. How to salvage old electronic equipment for valuable parts and IC's. Today we will look at an old, locally made Composite video to RF converter. I bought this to connect my Playstation 2 with an old TV at home.

DETAILS (as on device):

Pooja Audio-Video To RF
Video C.D. Converter
Model V-CD 250
Made in India

How this works is you connect your composite video (yellow) to the black connector at the back and one audio (no stereo) to the red and the RF output to your TV RF input (old televisions had this, if you are from that era). Set at appropriate channel and fine tune with the pots at the back and see the magic happen.

Now this little device is useless, most of the television sets that come these days are equipped with composite connector (Yellow, Red, White), even those are near extinction, being replaced by HIdef protocols like HDMI. So, I did what any sensible hobbyist would do, salvage the parts.

Observation:

1. Pretty good number of useful parts like 2 pots, 1 Fuse holder etc

2. Came to know which IC was used to convert composite video to RF. TOSHIBA (Jap) TA8637BP

Parts Obtained:

2 Composite(RCA) female sockets: They were extremely useful for some of my projects.

1 RF male socket.

2 potentiometers with nice black knobs: unknown resistance range, can be checked.

1 Fuse holder: Never had one of these, can be useful.

1 Composite to RF converter IC: TOSHIBA (Jap) TA8637BP: This was the only IC on the board. I think this IC can be used to broadcast a signal by antenna with a Compostie video input. Have to try it out. Click here for TA8637BP datasheet.

Parts discarded:

There were a few parts that I did not take from the Converter, it is ultimately your choice.

1 Transformer: Unknown I/O voltage, but measurable.

1 Power capacitor.

<several> Resistors and inductors.

<several> wires.

1 Switch: Can be useful.

1 KIA 7812p: Generic 12 Volt Regulator by KIA, can be useful.

That is all for now, keep an eye on The Salvage series for interesting salvages from old devices.
Happy Tinkering!

Moving Blog from Wordpress to Blogspot

2010-09-06T11:45:00.000-07:00

I have moved from my wordpress installation to a blog on blogspot. This move may seem contrary to what I thought before. But I needed something simple to deliver information with the flexibility of an editable interface.

The free account on Blogspot allows you edit your basic HTML template and create HTML/Java Script Gadgets which is not allowed on the free account of Wordpress. As for my wordpress installation on the server, it was too flexible to maintain and my free hosting (www.freehostia.com) suddenly stopped parses from external IP's, in short I could not use Google Analytic and Askimet without paying them for an upgraded account. I do not want to do this for my for now.

Anyway, everything is working fine. I will be writing on a lot more topics now. Keep an eye on the side bar categories and the Pages.

PHUN simulation: Rocker-Bogie Design for CE Bot

2008-12-14T00:24:00.000-08:00

We are working on a project by Crazyengineers.com, the CE Bot (visit the link for more information and see Appendix for more links). While discussing the appropriate suspension/chassis design, we thought about implementing a Rocker-Bogie system inspired by the Mars Roves Spirit and Opportunity Designs.

To get an idea on how the Rocker-Bogie design would work, I tried to simulate the construction on a free fun 2D sandbox physics simulator, PHUN. The simulations are 2D, i.e only lateral suspention simulation is possible, cannot simulate roll and yaw.

In the actual model, the other side would be connected using a differential rod with elliptical gearing on each side. This has to be further studied to be used properly. However, here is a small flash demo showing how each side will turn based on the other's motion [[LINK]].

Here is the video containing 3 simulations with explanations:

For more information on the ongoing project and our collected resourses visit:

CE Bot Google Site

CE Bot Forum Discussion Part 1

CE Bot Forum Discussion Part 2

CE Bot Forum Discussion Part 3

My visit to CNN and GeoTV @ Dubai, U.A.E. Part 2

2007-11-27T19:53:00.000-08:00

You must have have read about my visit to CNN in the previous post where me and an old friend of mine visited the Middle East CNN office. We finished off by exchanging cards, not exchanging, she gave hers. We exited the office thinking how lucky we were to see an inside of a CNN office. While getting down the lift, we stopped on the 3rd floor because of the colorful direction boards and company names. We came across companies like Cybertronix, 7 Cube etc, but none were open, so in the spur of the moment we decided to visit Geo TV (Urdu News Channel from Pakistan). Half of the whole 3rd floor was given to them.

We entered the office, no receptionist. We introduced ourselves to a person sitting next to the reception and asked if someone could show us around. He looked puzzled which was understandable considering not many barge in like this - he asked us to talk to a guy sitting behind us. He was the broadcasting Station Head; Mr. Imran M. Well, Geo TV is Pakistan's premiere news and entertainment channel like ARY and local PTV group. He gave a huge smile and said, "So, you guys are students? Want to have a look around?". We had huge grins on our faces. He took us to the News station area where they receive feeds from all over the world from other stations and journalists or Routers, AFP, AP etc. The edit all that, translations, voice overs, etc and give it to the area where its put in line with the anchor talking about specific news pieces, the studio where the anchor sits (for example, while we were there it was Hamid Mir). well, just for your information they all use Apple Mac computers for the technical work.

He took us around the technical department where the technical head told us all about the processing, the advertising list, program list, and how they use a fractal generator for the channel logo. Showed us the processors where final audio-video encoding takes place for it to be beamed to the satellites (They use 2). One of them is a UAE government up-link station, Samacom and the other system is their own backup.

He told us about the Geo Group in Pakistan and how it is a huge company comprising of magazines, newspapers and entertainment channels. We asked about the present Pakistan emergency when he really got passionate about the work they do and how they are protesting against it. The news anchor, Hamid Mir wore a black badge on this right arm, and their logo was black-and-white. They were the first one's to know about the emergency and had a small timer before Musharraf declared the emergency. They even knew about Musharraf's secret UAE visit to meet Benazeer Bhutto and their collaboration about something. Wow, in my mind I thought I knew a lot about this, when he interrupted my thought saying politicians are very shrewd in showing the right face at the right time, and being someone else in different situations.

Anyway, we concluded by watching the news being recorded and edited on the fly by some crazily talented PCR (Production Control Room) guys. We even visited the sets of some TV programs that are shot exclusively for Geo TV like the Kamran Khan Show.

As an update, just 4 days after our visit, the Geo TV station was closed down due to the emergency declared in Pakistan. It was a front page news and many of the employees we met on that day were seen protesting the closure. Read more about it on :

Pakistan State of Emergency, 2007

Musharraf Imposes Emergency Rule

Wiki on GeoTV Ban

My visit to CNN and GeoTV @ Dubai, U.A.E. Part 1

2007-11-16T00:43:00.000-08:00

Last week a friend of mine, an old family friend, landed here in Dubai, Emirates. His name, Aamer Mansoor Trambu, a final year student of journalism, Mumbai, India (presently in Ryerson Uni, Toronto, Canada as an exchange student). We had our friendly exchange of life stories and usual recording of random video clips for our own music video (he wanted to showoff what he learned at the school of journalism and I wanted to showoff my Adobe After Effects skills). By the end of the day, suddenly, we decided to do something I had always wanted to for a long time. Visit random companies and pester them with a million questions about their work (and ofcourse learn at the same time, while keeping their irritation at a minimum). So we decided to head to CNN at Dubai Media City.

Now before I talk about the visit, I want to get something off my chest. Generally students, as far as I know in my college, think its not possible to get companies to show them around. This might be because our college professors never encourage us nor tell us how to go about requesting companies to do that and, sharing the blame, the students themselves are never interested. Very few students have tried it (successfully, but never shared their experiences, I don't understand why) and very few professors have told us to do so (these few professors are the reason I am still interested in engineering. For sure, if you try it the right way, companies would love to show you around as long as you truthfully tell them why you are there.

Moving on; I called 119 (Information services) and asked for CNN contact number. They didn’t have CNN listed, weird. Anyway, I know every infrastructure group building has a website, like

Media City (News, TV, Publishing, Magazines, Events management companies),

Internet City (Software, CorporateSolutions, TelephoneOp, ISP companies),

Knowledge Village (Institutes, Training, Colleges, and other companies) and

Academic City, Silicon Oasis, DubioTech and so on.

We got CNN’s number and Aamir called them up. The operator directly transfered the call to a sweet lady, Miss Samia (Initially she got confused and asked if we wanted to drop in our CV.). Samia asked us to meet the next day (14th Nov) at 12 pm. Wow, we could not believe it. CNN is just a call away!

The next morning I was in college for an hour to do our MATLAB assignments for which I would make a point to attend. Unfortunately, sitting for long in the computer lab caused a wild flareup of my hip joint (ankylosynig spondilitius) and took 20 min to just get down the lift which was about a few meters away. Fortunately the randomness of the flareup helped me this time when the pain reduced considerably on the way back home (talk about randomness). We reached home, got ready and took a taxi to Dubai Media City which’s (yea which’s is a new word) pretty near my house. We reached at 12:30, Late! It did not feel good even though we called at 12:00 and told her we would be late.

We reached and entered the nice building which had restaurants and coffee shops, took the lift to their floor. Everything was in place as it is in an office building, meaning we found our way to CNN without any problems. There was a guard sitting at the front desk, we asked for Miss Samia and he told us to wait. She came in a min later, asked if we would like to have something and took us to the main … hall, that was it, CNN middle east was just a hall with two rows of tables; a Senior editor (in a room), editors, maybe a few technicians and a journalist! This amazed us at first, we thought CNN, a huge brand of Time Warner, to be a whole floor of the building, but it was just a hall. She made it clear to us why. Technology and need. CNN’s parent company is in Atlanta, USA. CNN Dubai is for arabic.cnn.com and they basically write articles/reports in Arabic for the ME region from this office. Online videos on the Arabic website is edited, post-processed and translated here itself. Video footage/feeds come from all over the world to them, and again, technology has made it easier. All communications between various globally situated offices is done through the internet. They do not need an office here to broadcast their streams in the middle east. It's all done from UK for CNN International, Hong Kong for Asia Pacific and South-East Asia.

We asked about their role as journalists while getting news from ME, and said most of it comes from their own CNN sources or through AP, AFP, Routers etc and each story has to be conformed by at least 2 sources before they publish it. If they need to cover something important or live, they can rent a news van, hire a freelance journalist/cameraman/sound engineer and so on. At that time she was working on a story. We ended the meeting by asking about internships. The most basic requirement is knowing Arabic and English and writing in both the languages. Having skills related to media management (video editing, photography, handling cameras, basic networking etc) is a plus. One thing I forgot to ask was where did they get the awesome CNN carpet? A Persian blue with huge CNNI (CNN International) logo all over it The whole meeting lasted for about 20 to 25 mins.

This is the end of Part 1. Coming next is something fun we did after visiting CNN; we visited GeoTV Pakistan without giving any heads up to them.

PC Parallel Port Interfacing Technique – Part 2

2007-08-27T00:19:00.000-07:00

Introduction

In this tutorial we will flash a LED (Light Emitting Diode) connected to your printer port socket. Reading the first part is recommended to get a general idea of what you are up to.

Connections
To connect a LED to your port first you have to know what it looks like. Shown below is the most common type of connector you can find on a PC.

LPT Pin Out [courtesy:
http://www.wkretak.pl/readarticle.php?article_id=5]

The Light Emitting Diode (LED)
Shown below is a very common Light Emitting Diode (LED) found anywhere from toys to computers.

Green LED and Red LED

Side View LED

In the above image the longer pin is positive and the shorter one is negative (ground). Our topic does not go into the details of how LED's works. For wiki info on LED, see here, http://en.wikipedia.org/wiki/Light-emitting_diode

If you have a LED looking like the one on the left (Green LED) then another way to know the polarity is to look at the side of the case. If flat, its negative. See the image below.

Top View LED

Schematic Representation of LED

It is recommended, that instead of connecting the LED and resistor directly to the port on your PC, use a long wire for easy reach. Connect the positive side of the LED into the 2nd data port as shown below. You should attach the LED with a 330 Ω resistor to limit the current. I have connected it without the resistor, which works, but is not recommended.

How to connect the LED to the parallel port.

After you finish this setup, it is now time to test the light! See if you have really found out the correct address by following the first tutorial then download this ( http://www.beyondlogic.org/pardebug/spp20.zip) to have real-time control over your Port to test the light.

Screenshot of SPP 2.0 from Beyond Logic .org

Open the executable; you should see a blue screen with port addresses, pins and their description. Choose the address where you have connected the port wire. Click on PIN 2 (Data 0) (there should be a cross on it now). Look at the LED, it must glow. If it does not glow, try a different Port address, LPT1, LPT2 etc. If it still does not glow, check your connection, something must be loose.

Programming the Parallel Port in C, C++, VB or Java with Windows XP or above, is not easy since it does not allow you to access the Ports directly. After Windows 98 all hardware control was virtualized.

Dont hesitate, ask me if you have trouble with anything.

Some Useful links:

http://www.epanorama.net/circuits/parallel_output.html : A very detailed look into the Port basics and programming.

http://www.logix4u.net/ : Excellent for explanation on Win NT/XP programming.

http://www.beyondlogic.org/pardebug/spp20.zip: Program to control parallel port pins individually.

http://www.beyondlogic.org/pardebug/pdebug.htm : The Debug program to test your parallel port with LED

PC Parallel Port Interfacing Techniques – Part 1

2007-08-26T23:45:00.000-07:00

Introduction

In this tutorial I will introduce the PC Parallel Port and how to identify its address for use in home electronic projects. Remember, the whole process and learning takes time but is fairly easy later on.

The LPT or Printer Port [courtesy: LadyAda,
http://www.ladyada.net/make/digg/programinterface.html]

The Parallel Port is (updated 2010) was the most commonly used port for interfacing usual devices like printers and scanners. It’s found commonly on the back of your PC as a D-Type 25 Pin female connector. Did you know it can even be used to make home projects?

LPT port Pin Out

The Line Print Terminal (LPT) port will allow input of up to 9 channels and the output of 12 channels at any given time, thus requiring minimal external circuitry to implement many simpler tasks. These outputs can act like switches in some cases or simply to light up LED’s. The inputs on other hand can act like pushbutton inputs to your PC to control software or hardware.

On the left you can see what individual pins stand for.

For your LPT to work with a printer, it uses internal software protocol for smooth communication. We won’t go into the details of this since it has about 5 different modes of communication. All we need to know is how to connect your little lights and switches to your printer port using the most basic mode!

Hardware Properties
Scroll down for the table of Pin Outs Here for clear explanation.

The output of the Parallel Port is normally TTL (Transistor-Transistor Logic). The voltage levels varies from port to port, either 5V or 12V. The current you can sink and source also varies from port to port. Most Parallel Ports can sink and source around 12mA. However these are just some of the figures taken from Data sheets. They vary quite a bit. So be careful not to overload your Printer Port.

Port Addresses
When the computer is first turned on, BIOS (Basic Input/Output System) will determine the number of ports you have and assign device labels LPT1, LPT2 & LPT3 to them. Usually the address for LPT1 is 378h.

To know your Parallel Port address, do the following on Windows XP or lower versions of windows:
Go to Start > Control Panel > System > ‘Hardware’ Tab > Click on Device Manager > Look for ‘Ports’ in the device list > Double click on LPT1 > Click on the ‘Resources’ Tab. In that you can see the starting address of I/O Range. That’s your number.

In Vista and above:
Click "Start" > Search for "Device Manager" > Look for ‘Ports’ in the device list > Double click on LPT1 > Click on the ‘Resources’ Tab. In that you can see the starting address of I/O Range.

This address called the Base Address is where you send commands to your Port to control their output or input behavior.

Please note that many new PC's do not come with an LPT port at all. They are now mostly obsolete and being replaced by the faster, newer USB ports. Interfacing a USB port is a completely different thing altogether.

See the next tutorial to know how to program your LPT to control an LED light.

Sources:
http://www.beyondlogic.org/index.html
http://www.lvr.com/parport.htm

*The above picture has been taken from: http://www.lammertbies.nl/ Thanks a lot.

Robot Navigation; "Where am I going?"

2007-03-13T17:14:00.000-07:00

J. J. Leonard and Hugh Durrant-Whyte, in the last decade, briefly described the general problem of mobile robot navigation by three questions:

"Where am I?"

"Where am I going?"

and "How should I get there?"

I was shocked to realize that these 3 basic questions which we, of course take for granted(!) are actually immensely complex implementations in robotic systems.

What I found interesting is that to date there is no truly elegant solution for the "Where am I?" part. A collection of many partial solutions can roughly be categorized into two groups: relative and absolute position measurements. Because of the lack of a single, generally good method, developers of automated guided vehicles (AGVs), unmanned flying vehicles (UAV's) and mobile robots usually combine two or more methods, one from each category. These two super-groups can be further divided into sub-groups as shows below.

Relative Position Measurements

1. Odometry: This method uses encoders to measure wheel rotation and/or steering orientation. Odometry has the advantage that it is totally self-contained, and it is always capable of providing the vehicle with an estimate of its position. The disadvantage of odometry is that the position error grows without bound unless an independent reference is used periodically to reduce the error [Cox, 1991]. This little technique can also be found inside ball-mice!

2. Inertial Navigation: This method uses gyroscopes and sometimes accelerometers to measure rate of rotation and acceleration. Measurements are integrated once (or twice) to yield position. Inertial navigation systems also have the advantage that they are self-contained. On the downside, inertial sensor data drifts with time because of the need to integrate rate data to yield position; any small constant error increases without bound after integration. Inertial sensors are thus unsuitable for accurate positioning over an extended period of time. Another problem with inertial navigation is the high equipment cost. For example, highly accurate gyros, used in airplanes, are exorbitantly expensive. Very recently fiber-optic gyros (also called laser gyros), which are said to be very accurate, have fallen dramatically in price and have become a very attractive solution for mobile robot navigation for hobbyists and university research projects.

Absolute Position Measurements

1. Active Beacons: This method computes the absolute position of the robot from measuring the direction of incidence of three or more actively transmitted beacons. The transmitters, usually using light or radio frequencies, must be located at known sites in the environment. Also known as 'Triangulation'.

2. Artificial Landmark Recognition: In this method distinctive artificial landmarks are either placed at known locations in the environment. The advantage of artificial landmarks is that they can be designed for optimal detectability even under adverse environmental conditions. As with active beacons, three or more landmarks must be "in view" to allow position estimation. Landmark positioning has the advantage that the position errors are bounded, but detection of external landmarks and real-time position fixing may not always be possible. Unlike the usually point-shaped beacons, artificial landmarks may be defined as a set of features, e.g., a shape or an area. Additional information, for example distance, can be derived from measuring the geometric properties of the landmark, but this approach is computationally intensive and not very accurate.

3. Natural Landmark Recognition: Here the landmarks are distinctive features in the environment. There is no need for preparation of the environment, but the environment must be known in advance. The reliability of this method is not as high as with artificial landmarks.

4. Model Matching: In this method, information acquired from the robot's on board sensors is compared to a map or world model of the environment. If features from the sensor-based map and the world model map match, then the vehicle's absolute location can be estimated. Map-based positioning often includes improving global maps based on the new sensory observations in a dynamic environment and integrating local maps into the global map to cover previously unexplored areas. The maps used in navigation include two major types: geometric maps and topological maps. Geometric maps represent the world in a global coordinate system, while topological maps represent the world as a network of nodes and arcs.

5. Global Positioning System (via wiki): A GPS receiver calculates its position by precisely timing the signals sent by GPS satellites high above the Earth. Each satellite continually transmits messages that include

the time the message was transmitted
precise orbital information (the ephemeris)
the general system health and rough orbits of all GPS satellites (the almanac).

The receiver utilizes the messages it receives to determine the transit time of each message and computes the distances to each satellite. These distances along with the satellites' locations are used with the possible aid of trilateration, depending on which algorithm is used, to compute the position of the receiver. This position is then displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units show derived information such as direction and speed, calculated from position changes.

The area of robot navigation is still in active research stage. Furthermore, its an interdisciplinary field. If you are considering of incorporating a reliable Sensor or Transducer in your project then keep these few lines in mind:

What are your needs/requirements? How much accuracy do you require? Precision? Analog/Digital? Software or only hardware implementation?
Power requirements.
Cost! This can even challenge your accuracy and implementation type. Compromises are inevitable!
Design. Another important consideration. Could be even a biological nano-bot, or a new GPS system for your car.

Keep these things in mind and spend sometime in trying out new methods. Who knows you might come up with a technique of your own or an idea for your current project? For example I recently came to know that old computer ball-mice used 'IR Shaft encoders' with about 64 pulses/rev of resolution. Well, for me that is some interesting piece of information.

MIT Open Course Ware

2007-02-21T00:16:00.000-08:00

MIT OCW (Open Course Ware) is an amazing initiative from one of the world's best engineering universities, MIT (Massachusetts Institute of Technology, Boston, MA).

The OCW provides online coursework on various topics ranging from Architecture, Engineering, Management to Arts, Humanities and Social Sciences. The course work can be found in formats ranging from PDF files to recorded class lectures.

Visit the main website to find topic of your interest. They keep updating the pages so I'm not going to post many links here except one.

As an example, here is a video on Basic circuit analysis methods, Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL) method. (Lecture by Prof. Anant Agarwal)

How to FM tap your neighbors telephone

2007-02-16T20:43:00.000-08:00

In short: "Listen in to the telephone conversation on your radio!"

But before you try this, a disclaimer:

All information provided in this post is for educational purposes only. I do not support nor encourage this monkey business. If you choose to make this device; you, and only you will be responsible for the consequences. Happy building!

Lets move on.

I had taken my old ~~Landmine~~ Landline (wired) phone and thought of making it a cool spy device. You know like in the ~~Bond~~ Austin Powers movies, only difference being, this one's a little bigger. Click on a image to "enlarge" it.

I don't have to explain what I'm going to do with this or what this is.

Click here ˅ to ...you know, read more:

The toughest time I had was removing the screws. Ultimately found a fit and undid this box.

Internals: On the left is the FM transmitter and right is the original phone. And you can even see the antenna stuck with hot glue around the casing of the phone. Another trouble I had was with the power supply to my FM Transmitter. I took 5V from somewhere in the back, Very hard to find and solder to. Be very careful here, don't short anything and please for the sake of mini-me put in a 220~470 ohm resistor.

Click on image for a reallll clooosafeel.... *electronics make me h-----* Shows the connections with the speaker- and speaker+ of the handset connection. I think you can figure it out why I did this. You can listen to both the talker and the 'talkee'~. Right?

Here shown is a cheap FM Transmitter tuned at about 90~95MHz depending on distance, interference, cheapa$$ receivers and random people coming in between.

This is all there is to it. Its really simple. Can be done to any phone, just take care of the power supply to the FM transmitter and the antenna. Drop in a line if you have any Q's. ill try to answer as soon as I can.

Now & Next 2007 Digit-all!

2007-01-28T23:04:00.000-08:00

Lifestyle Next_

Comfort is our primary need. We have strived for ages to make our lives comfortable. From fire which keeps us warm and have great food, to shelter and work to keep us busy.

The new times are making us more comfortable and 'content' but with a price. Couch potato is a familiar term and we all know it affect us with increasing ease of technology. I am really afraid to predict the future where we have personal robots, automated homes and human-machine interface. Maybe we will just lie down and live our lives (If it's ok to call it a "life"). Visit office from home; get food by robots, open windows/doors with the mind, brush teeth, automated flirting algorithms, and more scary automated 'stuff'! Anyway, let's be optimistic.

Travel Next_

GPS, extended information services, localized database, Google Earth and the top travel sites! What's next? Personally, in travel I would like as little digital intervention as possible but we can't help it, since we are living in digital world. A bits and byte world in our hands; anywhere, anytime. One with a laptop and internet connection can go anywhere she or he wishes to and document the travel digitally. I guess we engineers got a handful job making peoples life easier with great software solutions.

Education Now_

I believe the present way of education is a waste of time; not completely though. Creativity comes from solving problems yourself. Making the brain find a way, exercising it, testing our limit makes us more analytical and ready for the next problem. The problem with the current system is that we are not at all encouraged to find our own way. There may be a few exceptional teachers who work really hard to induce motivation but they are, as I said, few. Normally we have to 'learn' a way, use it and get the result on how many ways we 'remember'. It's a sad way to teach our generation the Art of Engineering, the thinking process, its creative soul. One fact remains; the change is a mammoth leap and a continuous endeavor.

Education Next_

The OLIN experiment; Interdisciplinary, project-based approach emphasizing entrepreneurship, liberal arts, and rigorous science and engineering fundamentals are the curriculum they have and this is an approach we need in most of the colleges. One point to be noted is that, this kind of move requires a lot of effort from academicians, teachers and intellectuals. The students have to be motivated to learn what they came to learn! Half of us don't even know what we are doing. Don't you think so? Maybe an exceptional few who realize and try the better way; applying what they have learnt practically. This approach is a must!

Entertainment

Video Now_

From S-video, Composite to the latest HDMI (High-Definition Multimedia Interface); the thrill of pure uncompressed, high quality video entertainment is in! Since the technology is newborn and expensive, another 5 years or so, HD media players and HDTV's will be on the rise.

Video Next_

How about cloths that change color to match your mood? Or hospital gowns that displays vital signs and x-rays on the person? MIT is researching on a 'display' that can be integrated in cloths, bags and ultra thin pads, called the 'Urbanhermes'! In the future there will be no need to replace paper since we will have electronic ink. Electronic ink is an interesting topic and pretty vast so here is a link for you to check out.

Audio Now_

From digital signal processing improvement to advance Artificial Intelligent audio processors; these wonder devices can reduce noise, calculate area acoustics and generate better sound and pleasure our human hearing to a pleasant level. Just like HD video, we have Dolby Digital – EX, Live, surround EX and Plus which can run up to 13.1 channel surround!

Audio Next_

Networking has brought shrunk the globe. Now will it shrink the Music Industry? With advances in Podcasting, online music stores and cheap distribution techniques, I think the next generation of music will be just online. No CDs, but direct streaming on our 'connected' devices!

The pictures I have included above are taken from various sources like MIT, OLIN College, Google image search etc. Check the links for respective owners. Credit goes to them. Copyright ©

Infra-Red Camera Modification

2007-01-28T18:17:00.000-08:00

I had an old Genious G Shot D211 lying around, and it was pretty much useless because of its obsoleteness.

After reading a lot of tutorials on making IR cameras, I thought ill do one myself. Making one is not exactly 'making' it, rather modifying or hacking an existing camera. It can be done to any model, but remember every model has a different type of IR filter in it.

I have included some images for you to see how pictures look like on the IR spectrum.

There are several types of IR filters included in a digital camera.

Some can be easily removed, these are separate glass lenses mounted on the same casing as your main focus lens, but removable when you open the setup. Some have to be broken like mine, which is on the same casing as the main lens, but glued to the casing. Some are painted on the main lens like nail polish either with IR on one side and UV filter paint on the other side or both on the same side. These have to be scratched, which is a very delicate process.

After removing the IR filter you get an image which contains spectrum information all over the range [See the first image, on the left]. To get only IR through to your sensor, you use a simple, fully exposed, tape of negative. What this does is, it blocks the visible spectrum from entering and allows only IR/UV. However, the CMOS sensor cannot detect UV very well, so you get just the IR spectrum. Here are some images.

Some useful links have been provided to check out other mods and hacks and the theory of IR Photography.

Without IR/UV filter.

With fully exposed negative.

Without IR/UV filter.

With fully exposed negative.

Electric Stove, full heat.

Electric Stove, full heat, closeup.

Electric Stove turning off.

CMOS Image Sensor Technolog

Awesome article on basics of light, detection methods and CMOS and CCD technology. This one answered a lot of questions of how sensors pic up different frequencies of light and calculates the needed one.

Notes on Image processing in CMOS

A short but involving article on how CMOS sensors interpolate and correct the pixel colors they receive.

Professional IR Photography

Explains how to take proper photos with different cameras and also explains the basics of IR photography. A very nice read.

Links to other homemade IR projects:
Infra Red Webcam
DIY IR Security camera

TechToys: The Mobile History

2007-01-26T23:59:00.000-08:00

Can you imagine how telephones were back in the 80's? Compare them to the mobiles now. I'm just talking about a few 20 some years. Imagine those brick like 'devices' talking pictures (black and white?) and playing music. Difficult to do so. I can not start to dream what Graham Bell would do with an iPhone. So lets take a look at the interesting and lively past of these little boy toys and how they turned from washing machine to a matchbox.

The history and development of 'mobile phones' is a very deep and fascinating one. Actually, in the true sense of 'mobile' communication, the walkie-talkie was used in the second word war (1940). However, that was just 2 way, looked like a microwave, weighed about 40 kg and not within the commercial network. Likewise, in 1936, the Motorola Police Cruiser mobile receiver was the first entry into the new field of mobile radio communications. Just six calls could be made before the car's battery ran out. The same technology was introduced in Sweden by LM Ericsson in 1944 (you know, the Ericsson in Sony-Ericsson).

On July 28, 1945 a cellular radio (small zone system) was first described in print in the United States. The head of the Federal Communications Commission, the FCC, outlined a two way radio service. Weirdly, FCC never allocated the spectrum needed for this service. Still, radio engineers were thinking of cellular, even if they couldn’t build such a scheme yet. A year later on June 17, 1946 in Saint Louis, Missouri, AT&T and one of its regional telephone companies, South-western Bell, began operating MTS (Mobile Telephone Service). Motorola built the radios and Bell System installed them. MTS was modeled after conventional dispatch radio. A centrally located antenna transmitted to mobiles moving across a wide area. The mobiles, all of them car based radio-telephones, transmitted to several receivers situated around the city. The traffic from the receivers and to the transmitter was connected by an operator at a central telephone office. Unexpected interference between channels soon forced the Bell System to use only three channels.

In December, 1947 Bell Laboratories’ D.H. Ring, with help from W.R. Young, articulated a true cellular radio system for mobile telephony in an internal company memorandum. Better technology would help, but more spectrum and channels, were essential to developing a high capacity mobile telephone service. However we all know, as the stakes get higher for a potentially remarkable technology to evolve and expand, politics play an imperative role. The Federal Communications Commission allocated a few more channels in 1949, but they also did something unexpected. They gave half of those frequency allocations to other companies wanting to sell mobile telephone services.

At the time of all the competition, on July 1, 1948 the Bell System unveiled the transistor. As we engineers know, it would revolutionize every aspect of the telephone and communications industry. Improvements came, more channels allocated, more subscribers poured in. In 1964 the Bell System introduced Improved Mobile Telephone Service or IMTS. Within no time they reached the peak of about 600 subscribers! Till mid 60's many countries other than US were also working on this field and came about as close as US in the technology. Within this time Japan had adopted the quality first approach in Electronics which boosted their respect and exports. In 1967 Nokia was formed by consolidating two companies: the Finnish Rubber Works and the Finnish Cable Works. Nokia expanded Finnish Cable Works electronics division to include semi-conductor research. Something that really helped the Finn's was a free market for telecom equipment, an open economic climate which promoted creativity and competitiveness. Unlike most European countries, Finland’s PT&T was not required to buy equipment from a Finnish company which gave them a choice. Nokia’s later cellular development was greatly enhanced by this free market background and their early research.

Back in the US, there were delays, lawsuits and objections from radio common carriers, independent telephone companies and their suppliers. All three groups feared the Bell System would dominate cellular radio if private companies weren’t allowed to compete equally. In the time they argued their case with FCC for open market rules, Bell System was already working on cellular radio. In January, 1969 the Bell System made commercial cellular radio operational for the first time by employing frequency reuse in a small zone system. Passengers on the Metro-liner train running between New York City and Washington, DC found they could make calls while on the move. A computerized control center in Philadelphia, Pennsylvania, managed the system. In fact, the first commercial mobile phone was a payphone!

There was another innovation which revolutionized everything from computing to communications. In November, 1971 Intel introduced the first commercial microprocessor, a miniature computer on a silicon chip, the 4004 which contained 2,300 transistors and did 92,000 single word ops per second and had 640 bytes of RAM. In comparison, today's transistors contain about 291 million transistors and does trillions of calculations per second! Due to this, several older services which required human operators were being replaced by automated systems. Then in 1973 Motorola's Dr. Martin Cooper made a call to their contender Bell Labs with the first handheld cell phone, the DynaTAC (Dynamic Adaptive Total Area Coverage) portable radio telephone! What they had done was engineered the mobile pay phone into the first hand held mobile phone.

In 1976 there were 44,000 Bell subscribers with AT&T mobiles and about 20,000 people were on five to ten year waiting lists! Demand existed but licensed spectrum to accommodate them did not. Like all statistic analysts do, it was estimated that by the end of the century there would be a little less than a million subscribers. And as always, they had no idea what they were talking about. The new millennium came and a million phones were being sold every day! By now, 2007, after just 30 years there are more than 3 billion subscribers around the world! The ancient life of being alone and out of touch had vanished in a blink of an eye. In these years there have been staggeringly numerous developments like, AMPS (Advanced Mobile Phone Service), GSM (earlier Groupe Speciale Mobile, now known as Global System for Mobile Communications), CDMA (Code division multiple access) and TDMA (Time division multiple access), being just a few crucial of the many trialed and implemented.

The mobile is one of those rare things which truly have altered the way we live. Over these years the mobile has evolved into a multifunctional device which encompasses complex gadgetry and software. As well as trying to keep it simple and usable. Do you think we can get away with much more in these little wonder toys over the next 50 years or have we reached a point of saturation? Think about it!

-Varun Dhanwantri (c)

Resources:

Mobile telephone history TOM FARLEY

Lucent Technologies

Motorola

Telefonaktiebolaget LM Ericsson

Wikipedia Foundation

The Telegraph Group Limited, London 2007