Business Card, RevB
Sunday, July 23, 2017 at 03:20PM

I am working on RevB of the dice, PCB business cards.  Maybe you are visiting this site after having been given one of these.

I built up a bulk programming rig using a TQFP Socket and a USBTINY programmer. This is for bulk programming of REV B of my "Business Cards". I was able to burn these 19 chips in less than 5minutes. Longest part was getting the IC's into and out of the socket. Wrote a batch file that would quickly run the AVRDUDE commands needed to burn the fuses and write the HEX to flash memory and verify.

Some of you may have one of the original versions of this that I made a few years ago and handed out. Below pictured is the RevB prototype. I made a mistake on the prototype and had to cut a trace and reroute a wire. This will be corrected in the production version. Production version will use blue, not purple solder mask.

For the geeks, Here are the list of changes between RevA and RevB...
* I made the whole thing thinner by eliminating the battery clip and recessing the battery into the PCB flush.
* Eliminated a bunch of components, namely the pushbutton (was able to make the battery clip also function as a switch. * * Eliminated the current limiting resistors on the LEDS, I instead now pulse modulate the LEDS in software to reduce apparent power to them.
* Switch from the ATMEGA328 to the less expensive ATMEGA48
* Eliminated the clock crystal and instead use the internal oscillator on the ATMEGA48
* Eliminated nearly all vias and improved overall PCB routing. Intentionally went with an organic "curvy" PCB trace routing for aesthetics instead of the more traditional 45degree routing.


Article originally appeared on Damage Designs Custom Electronics (
See website for complete article licensing information.