Printing a PCB on a Quarter

In celebration of President's Day, BotFactory designed a PCB using a quarter that perfectly fits an ATtiny2313A MCU to flash an LED with enough space for a coin-cell battery (CR2032) and the battery holder on the back. The circuitry on the top layer of the coin has open pads (exposed copper layers) that act as VCC connection points. To avoid wiring, the battery is fastened by screw terminals.

"We used our SV2 insulating ink to print 5 passes over the surface of the quarter, leaving openings (or vias) where conductive ink could be deposited," BotFactory notes. "The screw terminals on the battery holder don't touch the edge of the coin, but with the help of washers, touch the surface of these pads, allowing 3.3V power to flow from the positive terminal to the microcontroller."

Initially the plan was to use ATtiny85 on FDR, but after deciding on a quarter. This minimalistic setup employs an eight-bit high-performance, low-power microcontroller that is based upon advanced RISC architecture — ATtiny2313A. Requiring now more than 30 minutes to create, this simple project doesn't do anything other than flash an on-coin LED.

Even though such projects do not give us much information on the usage of the PCB, this gives us an idea on how one can invent the use of a quarter as a metal-core PCB. Clearly a marketing stunt for their SV2 PCB printer, however BotFactory does not that anyone interested in getting the design files can contact them.