I’m open sourcing my txtweb app @pushmail – An app that’ll send push email notifications via SMS.

I’m still a noob. This is the first time I’m open sourcing my project. Hopefully, someone will review my code and provide some constructive criticism.

What is @pushmail

It is an SMS app on the txtweb.com platform with which users can get instant email notifications via SMS. If they choose to, they can read full emails and reply to them. The user just has to setup a simple email forwarder. http://suhastech.com/mail

The “I just want to get this working” guide:

I have spent a few extra hours to make sure this can be setup quickly. I try not to just dump the code. So, you can find some comments explaining the mechanism.

Download the source.

1. Fill the common.php files with the constants. The comments will guide you through.
2. Setup a catch all email daemon and pipe it to the file “fetch_email_from_pipe.php”. Make sure it’s executable (chmod 755).
3. Install the Zend PHP framework.
4. Setup a cron that executes “database_cleanup.php” regularly. It prunes old emails from the database.
5. Install the MySQL schema by running install/install.php
6. Fork and improve the code.

Brief Overview of “How this works” (Just for the curious ones)

Read the txtweb documentation to get the complete picture. http://www.txtweb.com/tutorials-and-resources

In this system, user’s email username/password, mobile number or other information are not accessible even to the admin.

I have two tables.

Table 1 has two column, one the “user identifier” (integer, which is really an auto incremented index) and the other with the “mobile number hash” (encrypted form of the mobile number) which is sourced from the txtweb APIs. This is later used to send push email notifications using the txtweb APIs.

When you send “@pushmail” (or whatever app handle you have registered) to the txtweb mobile number, the app generates a unique user identifier integer, converts the integer to a unique alpha ID (say xyz) and saves the mobile hash in the above mentioned table. Sends you back a text message to the user with instructions to setup a forwarder to the email address xyz@yourdomain.com

I have a daemon setup which catches all emails to yourdomain.com.

As soon as the user forwards an email to xyz@yourdomain.com, it catches the email, looks for the user identifier code, converted back to integer. If a match is found in table 1, the mobile hash is extracted and sends a message “Reply Z to open this email… Subject, From Address”. It saves the email on another table with columns “auto incremented index” and “encrypted email body”.

It generates a unique ID (auto incremented) for the email and saves the email encrypted with the user identifier integer as the key.

When user replies Z, it goes to another page with GET request, ?id=1234&txtweb-mobile=the_mobilehash.

It looks for the table where id=1234 (that was generated when you got the email), fetches whatever is in your encrypted email body column). It then fetches the User identifier integer using the mobile hash (the first column). Decrypts (symmetric decryption) the email using the unique identifier interger, this ONLY works if the user identifier code is right, else you will find gibberish text. So, only the user can open the email.

The unsolvable problems (Atleast, for me)

1. If a hacker somehow gets all my database files and wants to open 1 of your emails (There’s nothing more he can do, trust me), he could try a simple “for loop” that tries to decrypt trying all the unique identifier integer (currently 6000). Difficult but still doable with some crunching power. So, make sure you have secured your servers. Still, the hacker has no way of telling what’s who’s. Not a big security hole I guess.
2. The email parsing technique. With literally thousands of RFC rules, different email clients sending in their own standards, I just couldn’t write a “one code fits all” code to parse the emails. Hopefully, someone will improve this.

Let me know if you have any problems and/or suggestions.

Note: Make sure you have enables GPS. The usual GPS stuff, make sure you can see the sky (GPS cannot work indoors).  

Screenies:

Well, I could make my own in under Rs. 20 (50 cents). All you need is:

• Soldering Iron, soldering flux and the lead wire
• Hot glue gun
• Shielded USB Cable (I got mine from a mobile transfer cable)
• 12V AC Adapter (preferably 2 A). I just used my computer’s SMPS to achieve the same (According to Molex standards, Yellow=12v, Black=Ground)
• Some patience

There are two ways to go about this..

The quick and dirty way:

I’m took this route because, this just needs some basic soldering skill and I wanted play my Kinect ASAP.

1) Cut the Kinect cable at the end. You’ll find 6 wires.

2) Tin the wires (Google “tinning” if you don’t know how to). This just mean, you’ll have to remove a part of the insulation and add a little bit of solder on it.

Tiny Tip: Use a Nail Cutter to remove the insulation on the wire.

3) So, here are the details about the wires. Thankfully, Microsoft has used the standard color code.

Yellow / Brownish – 12 V source (That is, your adapter)

Black – Ground

White – Data -

Green – Data +

Red – + 5V (The USB power).

4) Slice up the USB cable and you’ll find similar color coded wires. Solder it to the Kinect Wires.  Red to Red, Green to Green. etc.

Note: Ground is Ground, there is no separate USB ground/AC Adapter ground. So, join the AC Adapter and USB cable’s ground (Black) to Kinect’s Black wire.

5) Add some hot glue after you solder every connection. So, they don’t make unnecessary contact. You could also try insulation tape but I’m unsure about the longevity of your homemade cable.

6) And…. you should have something ugly like this.

and a mess like this….

The neat and clean way:

I didn’t do this but one guy had the patience to do it. Picture speaks a thousand words. So, here goes:

 

Many people brag about having 8 – 16 GB RAMs but in fact very few people know what exactly it does. We generally seem to think that higher the RAM,  greater the speed. Actually, with emerging new technologies, that’s not necessarily the case. *

Like my other “how stuff works” posts, this is aims to general public and doesn’t go about specifics (mostly).

What is a RAM?

I actually want to explain this in a designers perspective (engineers rock!). Here’s a simple block diagram from my Electronics textbook. Look at it once.

When we tell storage, Hard drives come in to picture. Does this block diagram portray RAM? Just storage right? Now, I make a crappy statement that for a computer to work RAM is not needed. Say you’re a designer designing a computer. I have a processor, a hard drive, input output devices. Hard disk to read information, rotate and pin point (this is the right word) a sector and read it. Kinda like grahamaphone. Problem is that, this process is very slow. So, if I make a computer with just these components, Whatever be the processor speed, to read my information, I’m handicapped with the hard drive’s transfer speed. So, my computer will be as slow as the hard drive.

Now, you are give a brand new technology (lets call it RAM tech) whose transfer speed is super fast but they are very expensive. For commercial viability, we need cheaper goods. So, what you do is place the RAM inbetween the hard drive and the output. So, as soon as the processor dumps the processed data into your super fast RAM, the output is given to the computer screen. When you are not working with your computer, maybe to lift a dropped pen, the computer copies the output to your hard drive from your RAM. Some processes like visual rendering, don’t even do that. So, you need a lot of RAM to play games. RAM is like a buffer memory. Following is the basic idea of a cache.

With more RAM, you can dump more processed data, you can open a lot more tabs on your google chrome and still not freeze. When you exceed the RAM storage, you’re computer freezes. Freeze = hard drive speed. So, imagine a computer without RAM . So, yes, more RAM means More speed because you can hold a lot more temporary data.

* Now justifying my previous statement. Now Mr. designers gets another technology with twice the bus speed (say RAM tech2). You process some 3D model and get it on the screen. As this process is fast, the queuing of other processes will come down. So, temporary data can be deleted faster. Needing less memory to get the same experience. So, faster the bus speed means you can get your data faster so needing less memory.

Hope, I haven’t confused you. This is the difference between DDR2 and DDR3. DDR3 is almost twice as fast as DDR2. So, 2 GB DDR3 is equivalent to 4 GB DDR2. There are variants with different speeds of the same technology. DDR2 and DDR3 are not compatible with each other.

Also, there is this swap partitions. Also called as Virtual Memory in Windows. You can partition your hard drive to swap temporary data with the RAM and your Hard Drive when your RAM is running low. This helps if you want to open up a lot of tabs and applications. Though, this would not affect your graphic performance, it will stabilize your computer.

I have a lot of money, I can afford a Hard Disk sized RAM, Would that work?

At the end of the day, its memory. So, yes. Some Live environments (like Ubuntu, BartPE) use RAM as storage space. That’s why Ubuntu Live needs atleast 512 MB RAM. But obviously, you can’t live on 512 MB.

Commercially, these new age SSD (solid state drives) flash technology was used as RAM technologies 10-15 years backs. As expected, SSDs are super fast storage equipments as they have no moving parts and expensive. no wonder, MacBooks are fast!

However, RAMs aren’t ultimate. They are designed to forget stuff once you switch your PC off. So, in the end, speed comes at a cost.

All this is complicated tech. You have many types of RAMs from basic SRAMs DRAMs to high tech DDR3s. If you want to learn even more, you’ll have to go to college (I’m looking forward to that)

This would be impossible without Txtweb, the SMS backend of this system. Thanks guys. Cheers!

Advantages:
* Works on any mobile (the txtweb advantage)
* Free, no internet (the txtweb advantage)
* If you are using a smartphone, you’ll know the battery drain behind the generic pushmail app. This will take that out of the equation, hence, a very power efficient SMS app.
* Very Secure

In this app, I (the admin) will not know your email address, password, mobile number, nor will I be able to view your email.

If you are curious, here’s how it works. You (in this case, your mobile) are literally the key to opening your emails. Nothing else can open it.

Step0: You’ll need to opt out of NCPR registry to use this (If you’re in India). Send “STOP” to 1909 to do that. Do note that, this will also open gates for receiving other marketing messages.

Step1: Message “@pushmail” to 9243342000 (India) or 650 385 8882 (USA) (Save this number, I tell you. Very Handy).

Step2: You’ll get a forwarding address. This will be unique to your mobile phone. (something like xyz@smspushmail.com)

Step3: Now, go to Gmail and click on mail settings. (Little gear like icon on the top right corner). When the setting opens, click on the Forwarding and POP/IMAP tab.

In the Forwarding section, Click on Add a forwarding address.

Step5: A box should pop up. Type your forwarding address (something like “xyz@smspushmail.com” without quotes).

Click next and a message appears saying a confirmation code has been sent.

Step6: Don’t freak out seeing so many steps! It takes less that a minute.

Check your mobile, you should have received an SMS with your confirmation code.

In the sms, you will find the lines “Gmail Forwarding Confirmation (#59562304) – …etc”

Back in the mail, type the confirmation code. Only the number, no ‘#’ or the ‘()’. Click verify.

Step7: Set the forward a copy of incoming mail.

2) Click on “Save Changes”

Thats about it!

Notes:

• Threaded / Quoted reply supported.
• You can opt out of the service by messaging “stop @pushmail” and opt in by “start @pushmail”

The tutorial ends here. The following is for the curious ones.

Privacy Policy:

By following this tutorial, you send your emails to our servers. All your emails will be encrypted with state of the art AES encryption mechanism. You (in this case, your mobile) are literally the key to opening your emails. NONE of your emails can be touched. We just have a tunneling script that’ll sincerely help you manage your email.

Other email services?

Currently, this service supports only gmail. It will (most probably) work on email providers who provide email forwarding option. If you have any specific request, please comment.

Other Notes:

• Maybe if this takes off, I’ll buy a relavant domain (nintuitive.com is just some unused domain I had ). *check*
• If you hav suggestions/problems, email me.

It starts of with a bright day, you are dumped on a random generated map!! The maps are infinite( That’s right! It keeps rendering more as you keep traveling! ) Well, the game name says only a part about the game, that is you can mine! There is lot more fellas!

The game is still in BETA stage and already thousands are addicted to it and achieved the impossible. There’s no tutorial, you can look up online or figure out yourself…

The first few things you notice are the huge mountains, trees, water, ice and cubical cows! EVERY block in the game can destroyed, collected and place else where! (except the bedrock stone found VERY deep). It doesn’t end there, at night creepy zombies and spiders roam around! If you don’t have a decent shelter, they will kill you! The game is survival, exploration, experimentation and most importantly CREATIVITY!

Chop trees, make planks, build houses, collect rocks, make castle, lay tracks and make mine cargo system, add switches and make circuit connections, dig for gold and diamonds, slaughter monsters, kill pigs for meat… The list in endless!!

The first thing you have to do when the game starts is make a decent shelter for the night.. you don’t want to be around when the monsters come out in the night! You can expand later…

Make a work bench! How do you do it? Collect wood, convert them to wooden planks! Just place in the 2×2 crafting box and you’ll get planks! Place 4 planks in the crafting slots and you get a working bench!

Select the bench and click on the ground and pop! There ya’ have it! A work bench! Just right click to use it. What can you do? It has a 3×3 crafting slots, you can make tools like sword, shovel, axe, hoe, pickaxe etc You can just place a few rocks and sticks to get pickaxe.. You need to place in a specific pattern like so…

Also build a furnace so you can smelt the ores to get the metals… You can smelt sand for glass, cook pig meat etc

Now, start digging!! You’ll be needing lots of iron to make long lasting tools and you will rarely find it on the surface, you have to dig down for them!!

Warning: Never dig straight down, up or ahead! You keep digging straight down and you’ll end up in a lava pool or fall a great height! You’ll never know what’s below you! Don’t stick to the wall while digging ahead, the might gust out and burn you… Keep a safe distance and dig so you can block the lava before it floods the place!

Don’t like mining?? Farm then! Find seeds, plant, water them or plant them near a water body… You will get wheat after a few days, make hem into bread and eat!

Make sure you keep plenty of food in your inventory. You can kill pigs for meat. You can consume raw or roast them in a furnace!! There block do NOT obey gravity except for sand and gravel.

While exploring you will find some huge cave system!! You are likely to find plenty of coal, iron, gold and perhaps diamond if you travel deep down! Before entering make sure you have a weapon, plenty of food, necessary tools and a emergency grafting table. There will be monsters in the cave system! Carry LOTS of torches, it will be hell dark and you don’t want to get lost!

Set up base, near your spawn point just in case you die. Make sure everything is accessible from your base. Like water, caves etc. If you are creative you can make a huge castle or a nice home with windows and glasses. You will need a lot of resources but its not really that hard! If are going to travel a lot to different place and different caves then make huge towers on hills and light it up with torches! So you can see at night and not get lost!

Too complicated and boring? Want to have only fun?

Well, you can change the setting to peaceful mode and there will be no monsters at all! You can use InvEdit, and edit your inventory and get all the stuff you need!

I build a huge build and made a rollercoaster ride! That’s right! Place the cart tracks, place the carts, give a push and jump on to it! And enjoy the ride!

The game supports online play and LAN… Yes, more people, more fun!! Well start building your virtual world!

More awesome things made can be found on Youtube.

When I press the power button the first time, it does POST but does not detect my IDE hard drive. Then, it does not boot saying “no boot device” blah blah

After this, when I press reset (or quickly press the power button, twice), it detects my hard drive. So, my computer boots up my hard drive (Windows XP or whatever).

So, technically, the hard drive boots with a soft boot not a hard/cold boot.

I emailed Gigabyte support about this problem. As expected they gave me the default “Go to Hell” solution politely. Should I email those people to get template responses?

Anyways, heres the fix.

When will this problem occur:

I got myself a New Computer but was using my old IDE hard drive. So, my hard drive is a little bit old and slow. It can’t keep up with my new computer. The hard drive needs a little bit extra time to initialize after giving power.

The Fix:

We add a delay before the BIOS starts detecting (POST), so your hard drive will get detected every time you boot up (Yay!).

How do I do it?

Its pretty simple but the interface you get might be different from mine. Just try to find a “Delay for HDD” option in the BIOS setup.

• As soon as you press your power button, start pressing “Delete” or “F1” or “F8” (Depends on your motherboard manufacturer). Normally, its “delete”. By this, you’ll enter the BIOS setup.
• Switch to Advanced settings (For my Gigabyte board, I press Ctrl+F1).
• Now, select Advanced CMOS setup. There, you’ll find “Delay for HDD (secs)”. Set it to 2.
• If you still continue to have problem, increase it to 5 seconds or something (Note that this will increase your boot time)

It didn’t have a stereo (3.5 mm) port, just the Sony Ericsson connector. If you follow my blog, you’ll know that I’m the cheapest ass in town . I soldered in a stereo setup, here’s how.

1) Open up the Speaker using Torx 6 screwdriver (T6).

2) Solder the connection as per this pic. It also needs an external power source (+5V), you can use USB, a 5V adapter, or even a discarded battery

3) Here are some alternative points that I could find out (I broke the Sony Ericsson port *facepalm*).

4) Erm, thats it. Do all the cosmetic stuff (I <3 Hotglue) and Tada!

Playing on the hot seat (I mean the charging dock )

This time, I have a video for you. By this, I’m launching my YouTube Channel. There’ll be better videos so, don’t forget to subscribe

Before everthing, How humans perceive depth?
There are 2 ways we, humans, perceive 3D – Convergence and parallax. Most 3D technologies today take advantage of the convergence method. There is a slight difference between the images seen by each eye. That’s called Binocular Disparity or sometimes called, stereo vision.

If you think about it a little bit, you can actually formulate an equation to calculate the depth and name it, “your name here” formula of awesomeness . (psst….trigonometry). Here’s an infograph that’ll explain everything.

So, what 3D movie makers do, is simulate the whole 3D experience

• using 2 cameras filming the same event, one beside the other. (though computer animated movies work differently, completely software)
• then feed the left channel to the left eye and right channel to the right eye.

There are tons of ways to do that. I’ll try to show some of them.

Anaglyph technology (red-cyan or red-green):

This is mostly used in home entertainment systems because of the ease of setup. Just a normal color TV and a pair of 3D glasses would be sufficient. These are also used in these little comics. One thing you miss here is color. That might be one reason for its unpopularity.

Here, it uses basic color filters. The right glass (red) filters out the left channel (blue) and vis-a-versa.

Also, if you watch badly formed 3D movies which gives conflicting information to your brain, you might a headache.

Polarization:

Same principle, but here, color is retained. This is the preferred method used in big cinemas like IMAX, Disney etc. Next time you go to a 3D movie, try to look over to that projection box. You’ll find 2 projectors working. Each producing lights with different polarization. The purpose of 3D glasses is to feed each eye, these different images (again left channel to the left eye, right channel to the right).

One disadvantage would be the cost of the setup. The screen should be silvered to avoid losing polarization when reflected off the screen. So, its not used for home viewing.

Liquid Crystal Shutter Glasses:

This is the newest boy in town. Most manufacturers are releasing a 3D iteration of their TVs. Actually they are no different from a normal LCD but will have a high refresh rate and some emitters I guess.

For now lets say an LCD has 120 hz (120 frames per second) refresh rate. 60 frames of left and right images are shown alternatively. The left and right lens’ darken and lighten 60 times alternatively. Liquid crystals cause this to happen. Synchronizing information about when to darken and when to lighten can be given in a number of ways. Wired shutter glasses use wires (duh!). Wireless use IR emitters on the TV (that exactly is the specialty  of  these new age 3D TVs).

Why high refresh rate you ask me? Persistence of the human eye is about 1/100th of a second. So, if you have an LCD with low refresh rate, its smart enough to know that the TV is confusing it.

3D without glasses?

My mind has been wandering over 3D simulation, without 3D glasses. It seems that good folks over at the university of Arizona have cracked the puzzle making 3D holographic screen. Kudos to those people!!

Also, Toshiba seem to have found a solution using the parallax barrier method, which I previously mentioned.

Stay tuned for part 2 of this series (How to make 3D movies!).

I wanted to get a VGA Cable by which I could could connect my Xbox 360 to my monitor (Fights over the TV is quite normal in my place). I looked at the price tag of the Official VGA cable ($40!). At the end of of the its just a cable and it doesn’t deserve $40. So, I got myself a third party cable from this chinese website called play-asia for $10. It was of the worst build quality. Ghosting images all over the monitor (Bad shielding I would say). Even Gears of War looked like Left4Dead .

I had all the parts lying around. So, thought I would do it myself. Initially, I thought that building it myself would mean bad quality. It turned out to be a pretty good after all.

Shielding is basically a protective layer over your cables which prevent signal loss. If that is bad, ghosting would be evident. Also, Microsoft was kind (or cheap) enough to provide all the pins in all the connectors (use it or not) unlike PS2’s connector. So, you can try this with any cables. Standard Definition AV cable, HD component, VGA cable (though I see no point in doing that ) .. anything!

One surprising thing is that, I didn’t even use shielding cable and still didn’t get any ghost images. How? you may ask me? Simple, I just made the cable as short as possible. Leaving little scope for signal loss.

Also read: Connect headphones to your Xbox 360 VGA cable

1) Any standard Xbox 360 video cable. SD AV cable, HD component, etc. Even a third party cable would do. You just need the port.

2) Female VGA connector / port. (see the last pic)

3) 3.5 mm stereo connector (for audio). I got mine from an old tape recorder.

Here’s how you can do it:

1) Open up the Xbox 360 connector by cutting the sides of the head. I did a shabby job, here, but it didn’t matter.

2) After that, you’ll get a piece like this. Solder the connection according to the corresponding pinouts. Red to red, green to green etc. That is, VGA cable to the original Xbox 360 connector (I think you get the idea).

Don’t forget to solder the connections of your Stereo port.

3) Use some insulated tapes between the terminals (in the VGA port). To prevent shorts.

4) I put some super glue on the metal plate and fixed it on the plastic thing.

5) And Tada! (This is going to be my signature statement from now on )

It worked like a charm. No ghosting no matter what!

Also, thanks to Ben Heck @Engadget for the nice article.