How to flash your uC's fuses

While working on a project based on the atmega328, I needed to change the values for the fuses in order to use the external crystal and run at 16MHz (instead of the default 1MHz). Well, needless to say, I used the wrong values and basically said bye bye to the small uC. Some time later, while working on another atmega328-based project, suddenly the chip wouldn't respond to programming anymore, for no apparent reason. One more chip gone 😕

These uC chips are quite cheap so it's really not a big loss, but you still feel bad about it. While looking online for a solution, I found this website

HV rescue shield

It is basically an Arduino shield. It is quite simple to solder. They also provide the Arduino sketch you need to run to reset the fuses on your uC (atmega, attiny). It is fully open source, sketch, schematic, PCB layout, quite cool if you ask me 😃

Here's what you get after you're done soldering.
before soldering

Uploaded the sketch, set the serial baudrate to 9600 and boom:
before soldering

Both aforementioned chips came back to life.