Magically Repair AVR Chips

May 17, 2010 by Mike Szczys 30 Comments

If you’ve ever spent time working with AVR microcontrollers you’ve probably set the fuse bits incorrectly at least once. The ATmega fusebit doctor will automatically repair the fuse bits and get you back in business until your next mishap. The ATmega8 that powers the device has the chip signatures for the ATmega family stored inside so it will automatically detect which chip you’re trying to ‘unbrick’. From there it looks up the correct fuse bits and resurrects the sick microcontroller. This is useful in recovering a chip that has serial programming disabled, used the reset pin as I/O, or just enabled an external clock without the necessary hardware to deliver on that feature.

This magic is taken care of by using High Voltage Parallel Programming. We’ve seen HVPP used in the Arduino rescue shield and it is a valuable feature of the AVR Dragon, our favorite AVR programmer, as well as others. Still, you can hardly beat the ease of plugging a dead chip into this board and pressing one button. Oh, did you brick a member of the ATtiny family? There’s a rescue board for those too.

[Thanks Stewe]

Minimalist AVR Programmer Is Just Fab!

May 15, 2010 by Phil Burgess 62 Comments

Whether you’re burning a new bootloader to an Arduino board, or doing away with a bootloader to flash Atmel chips directly, an in-system programmer (ISP) is an indispensable tool for working with AVR microcontrollers. If cost has held you back, it’s no longer an excuse: FabISP is a barebones USB-based AVR programmer that can be pieced together for about ten bucks.

FabISP was created by [David Mellis] as a product of MIT’s Fab Lab program, which provides schools with access to design and manufacturing tools based around a core set of fabrication capabilities, so labs around the world can share results. But the FabISP design is simple enough that you don’t need a whole fab lab. It’s a small, single-sided board with no drilling required; the parts are all surface-mounted, but not so fine-pitched as to require reflow soldering. Easy!

There’s still the bootstrap problem, of course: you need an AVR programmer to get the firmware onto the FabISP. This would be an excellent group project for a hackerspace, club or school: if one person can provide the initial programmer to flash several boards, each member could etch and assemble their own, have it programmed, then take these out into the world to help create more. We must repeat!

[Thanks Juan]

Oscilloscope Doubles As A Serial Terminal

February 24, 2010 by Phil Burgess 25 Comments

PC-based USB oscilloscopes are fast becoming all the rage. [Matt Sarnoff’s] Terminalscope takes the reverse approach, adapting an oscilloscope into a full serial terminal. You may have seen something similar before in the Dutchtronix/SparkFun O-Clock, but [Matt’s] project goes one further by adding a PS/2 keyboard port for full bidirectional serial communication, and with much sharper display resolution to boot.

The mostly VT-100 compatible Terminalscope is built around two AVR microcontrollers: an ATmega328P runs full-tilt to generate the video signal and handle serial I/O, while an ATtiny45 handles keyboard input to avoid interrupting the ’328’s duties. Rather than vector trace each character, a raster-scanning approach is used: the beam follows a fixed X/Y path (like a television), while modulating the Z input (beam intensity) to form an image. The device can be connected to a PC via serial port or USB-to-TTY adapter, or directly to another microcontroller to debug serial output.

We recently showed an oscilloscope being used as a multichannel digital logic display. The Terminalscope provides yet another use for this essential bench tool and could nicely round out a “poor man’s” testing setup. The schematic and full source code are available for download.

Garage Door… Packet Sniffer

October 3, 2009 by Jake W 46 Comments

Some type of logger or sniffer exists for almost every form of electronic communication. Your keystrokes, phone conversations, and wireless networks could all be monitored. In this awesome proof-of-concept project, [James] expanded that array to include garage door openers. After receiving a piece of chain mail which stated that criminals have the technology to record any remote code and play it back, [James] wondered if he could build such a device that would work on at least his opener model. Continue reading “Garage Door… Packet Sniffer” →

Stop Light For HotWheels

September 21, 2009 by Caleb Kraft 48 Comments

stop

[Paul] wrote in to show us this little project he did for his kids. His children love playing with their toy cars. In an effort to give them even more fun while playing, [Paul] built a stop light for them. He’s using an ATtiny13 to run them and has the source code available on his site. Not only did the kids get a new toy, he got an excuse to go build something in his workshop.

Wireless RGB Light Bulb

September 20, 2009 by Jake W 15 Comments

Want to make the above yourself? [Sprite_tm] did a thorough job documenting the build step by step (complete with pics, schematics, graphs, and links to the parts used). In summary, [Sprite_tm] busted open an Ikea CFL bulb to reuse the housing. Inside, he installed a scavenged power supply, ATtiny44, RGB LED module, and a radio receiver. A remote control allows [Sprite_tm] to change the lighting of his room to nearly any color. The cost of the project is a little under $30. The price tag isn’t so steep when one considers the insanely long lifetime of LEDs.

Etching Agitator

August 15, 2009 by Caleb Kraft 22 Comments

[youtube=http://www.youtube.com/watch?v=yDA16dfqgeg]

It might be a little bit of overkill, but this etching container agitator sure looks convenient. There’s not much to it technically, a small circuit with an ATtiny45. For those beginning with this stuff, he has written a pretty good tutorial on working with basic microcontrollers. If you are more interested in a tutorial on etching, we did a guide on how to etch a single sided PCB.