Teletype Machine From An Electric Typewriter

February 11, 2010 by Mike Szczys 34 Comments

This project, by an unknown hacker, patches into an electric typewriter and uses it as a Teletype. An AVR ATmega168 microcontroller patches into the key matrix of the typewriter which allows it to artificially type. Now, data can be sent over a serial connection to the AVR for output on the typewriter.

We’re not quite sure what this is going to be used for. We’ve seen hacks like this for Twitter reading in the past but he makes no mention of that type of use. Personally, we’d like to have this just to “print” out the occasional letter. Typewriters are so rarely used these days it would be a bit peculiar to get a letter that has the dimpled impressions associated with slamming a die into a piece of paper.

More AVR Tetris

January 18, 2010 by Mike Szczys 11 Comments

[Ben] built an AVR based Tetris game that uses a TV as the display. He linked his project in a comment from the AVR Tetris project featured last week. His work taps the power of his own tvText library to handle the composite video out. Using a TV takes all of the hardware work out of the equation, leaving just the composite jack and a few buttons to connect to the ATmega168 and its 20MHz clock. We’ve embedded the game play video after the break. It’s black and white but also clean and crisp.

[Ben] didn’t include music with his build but another commenter, [Eric], has started to work on that. We can’t help but think that they both should have tipped us off sooner about their projects.

Continue reading “More AVR Tetris” →

AVR Tetris

January 14, 2010 by Mike Szczys 16 Comments

Tetris, the timeless classic, is one of those concepts that someone will try to run on every conceivable hardware platform. I took on the challenge of programming a Tetris clone from the ground up using hardware I had on hand. At the heart of the build is an ATmega168 microcontroller. The game displays on a KS0108 128×64 LCD module with five momentary push switches to provide directional, rotational, and input controls. You can see the resulting monochrome action embedded after the break.

I had several goals in mind while writing the code for the game. I wanted the code to be portable so that the size of the board and type of screen used could be easily changed. With that in mind I developed the trunk for a Nokia 3595 cellphone screen and a parallel branch for the graphic LCD. Originally I was working with an ATmega8 but upgraded so that I could operate at the 3.3v the cell phone screen required.

The firmware for the graphic LCD branch compiles to just over 6 kB which means it can still be run on a mega8. Also, the ATmega168 is the same processor used in the Arduino Duemilanove so another Tetris port is not out of the question. I just got a hold of my first Arduino so we’ll see if I find time to start a new branch in the code.

Continue reading “AVR Tetris” →

Modular Systems Using SPI

December 22, 2009 by Mike Szczys 5 Comments

[Humberto] is at it again with a NerdKits video detailing the use of an SPI bus to communicate between microcontrollers. He started with a previous LED marquee project which was limited to a 5×24 LED Matrix and developed a modular solution to increase the size limitation.

The writeup and video embedded after the break do a great job of detailing the important differences between a stand-alone and a modular system. The good news is that the ATmega168 chips being used have a built-in interrupt based SPI protocol. Once wired correctly, a master control chip addresses each module separately, adding data to their buffer until a full frame has been transferred, then moves onto the next module.

Some of the caveats to this system such as digital transmission over long distances are discussed. We do wonder about power limitations if all LED’s in the marquee are illuminated at once. But that concern aside, if you’re thinking of playing around with an LED display don’t forget that there’s usually a huge price break for orders of 500 or 1000 LEDs!

Continue reading “Modular Systems Using SPI” →

RFID Door Lock – The Right Way

November 17, 2009 by Mike Szczys 40 Comments

[youtube=http://www.youtube.com/watch?v=XT7E_GEIPVg]

[Pcmofo] has shared a well-built, well-explained example of how to implement an RFID key system for a door. We call this the right way because it is well thought out and functional. In the past we’ve seen doors that unlock via a secret knock, keypads, and RFID, but they are all non-permanent solutions capable being transplanted from one door to another. Rather than building a mechanism to turn the door handle, this implementation uses an electric strike mounted in the framing of the door to allow access. These are used for security doors in buildings and are built to keep your door secure.

The hack in this case is the electronics. Using an AVR ATmega168 running the Arduino boot-loader, [pcmofo] has prototyped a two-part design. An RFID reader is mounted outside the door with data wires running to the inside where the microcontroller resides. A hard-coded RFID card is used as a “master” to train any number of tags for entry. The master puts the device in training mode and the next tag to be read is added to the list of tags authorized to open the door.

We like messy wires and quickly thrown together devices but this is built to last and will look great once mounted in an appropriate enclosure.

Bluetooth Cartridge For Nintendo DS

October 21, 2009 by Mike Szczys 14 Comments

bluetooth-cartridge-nintendo-ds

We’ve received tips from a few different people about a new Bluetooth module that connects as a game cartridge for the Nintendo DS. This is a homebrew solution and not an official Nintendo add-on. The cartridge houses an ATmega168 microcontroller which provides the interface between the DS and a Roving Networks RN-41 bluetooth module.

They’ve provided a schematic for the device but we didn’t see any board artwork or pictures of the internals so you’re on your own for board layout. The libraries needed to use the bluetooth connection with homebrew software are up for download. This should provide a nice way to use the DS with a Bluetooth GPS module, or perhaps as a discrete Bluetooth sniffer and spoofer.

Universal Credit Card In The Palm Of Your Hand

September 23, 2009 by Mike Szczys 38 Comments

universal_credit_card

Do you remember the magnetic card spoofer in Terminator 2? It was a bit farfetched because apparently the device could be swiped through a reader and magically come up with working account numbers and pin numbers. We’re getting close to that kind of magic with [Jaroslaw’s] card spoofer that is button-programmable.

Building off of a project that allows spoofing via an iPod and electromagnet, [Jaroslaw] wanted something that doesn’t require a computer to put together the card code. He accomplished this by interfacing a 16-button keyboard and a character LCD with an AVR ATmega168 microcontroller. Card codes can be entered with the buttons and verified on the LCD. Of course this is still dependent on you knowing the code in the first place.

As you know, credit cards use this technology. We don’t think Walmart is going to be OK with you pulling this out in the checkout line, not to mention local five-oh. This technology is also used for building access in Universities, businesses, and hotels. If used in conjunction with some other spy technology you’ll be on your way to becoming a secret-agent-man.