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]

Ghetto Repairs: Desoldering With A Candle

May 13, 2010 by Caleb Kraft 66 Comments

Yes, that picture you are seeing is serious. [Roland] needed a chip for a damaged piece of electronics. He was lucky enough to find one on an old board at a local shop. The problem was, he didn’t have the hot air gun to remove the chip the correct way. Instead, he simply cooked the board over a candle to melt the solder. Interestingly, after he cleaned the candle-cooked board, it looked like it survived without damage. The chip worked fine and fixed his problems. Sometimes, we just don’t have the right tools for the job.

[via HackedGadgets]

Building Air Variable Capacitors

May 12, 2010 by Mike Szczys 14 Comments

In keeping with our opinion that radio operators were the original electronic hackers here’s a guide to building your own transmitting air variable capacitors. Using some roof flashing, Plexiglas, and various fasteners [David Hammack] was able to make it work. It’s not a perfect solution but he has some ideas to make the next one better. Give this a try after you’re done tweaking your crystals and building input devices.

[Thanks Rich]

5×2 Patch Board

May 7, 2010 by Mike Szczys 16 Comments

Sometimes we want to sit on the back porch, crack a beer, and do some prototyping. Other times we’d like to do the same but on the couch in the livingroom. To that end we added a 5×2 pin to 10×1 pin patch board to our solderless breadboard.

The 5×2 pin form factor is pretty common, used as an AVR programming header, on development boards like the Dragon Rider 500 and the STK 500, and in small prototyping devices like the Bus Pirate. We like the freedom of using IDC cables as interconnects and that’s where this board comes in. Now we can patch into the IDC cables yet still quickly disconnect them when moving to a different prototyping location. Check out the PCB artwork and this handy device in use after the break.

Continue reading “5×2 Patch Board” →

QFN Or MLF Soldering Without Solder Paste

May 4, 2010 by Caleb Kraft 22 Comments

[youtube=http://www.youtube.com/v/c_Qt5CtUlqY&hl=en_US&fs=1&]

Take a few minutes to watch this amazingly informative video on how to solder QFN or MLF components without solder paste. The quality of the video and the information within is quite nice. Even if you don’t intend to work with these parts, you could pick up some tips for soldering with hot air.

9 Digit Pulse Counter

April 30, 2010 by Caleb Kraft 11 Comments

At roughly $20 to build, this 9 digit pulse counter is an excellent example of home built tools. The builder, [Josh] found himself repairing a device and in need of a pulse counter. With the components cheaply available, he just built his own. He says that it has a few limitations, like display brightness, but overall it seems to do the job well. You can download the PCB from his site.

[via MakeZine]