This is it. Hopefully the second to last board spin. OSHPark Super Swift Service to the rescue.

There are a few things going on here. First off, this is the first board that's 'mr robot mask' shaped. We've already worked the kinks out of the prototyping boards (and firmware development is going swimmingly). We're doing one last go to make sure everything works before dumping $$$ on the custom soldermask process.

Secondly, we're moving to a better power regulator. The old version was a dumb linear piece of shit. This isn't going to fly with a battery powered badge that is supposed to last several days. This badge is using the MCP1640 boost regulator. It's simple, and it'll put out 3.3v for a while.

Power

The most difficult challenge for this badge is keeping it alive for an entire weekend.

Using measurements from the prototype badge, the four AA cells should last about 16 hours. That's with the lights constantly blinking on full brighness (the chip can do 8-bit PWM, so that's great), and constantly transmitting. I'm thinking this will be fine. If we cut the duty cycle of the LEDs in half, we're getting more than a day. If we don't transmit WiFi all the time, the draw from the ESP goes from 140 mA to 15mA. This thing will make it through the weekend.

By April, I should have an order in for the finished PCBs. Hopefully. By August, they'll all be sold.