This is a boost converter powered LED board. It’s intended to be populated with 21 SM0603UV-405 UV LEDs, but really any 0603 LED would work just fine. The boost converter is the AP3015. The two 1210 caps are 10 µF, the inductor is 10 µH and the diode is an MBRA340 Schottky diode. The resistor divider values of 51.1kΩ and 3kΩ yield an output voltage of 22.14 volts, or 3.16 volts across each LED (there are 3 parallel strings of 7 LEDs in series). It’s recommended that the input power be 9 VDC.

The “S” in SAO now stands for Serial.

This SAO will connect two badges together in a null modem arrangement, wiring one badge’s TX to the other’s RX and vice versa.

Put two shrouded 2x3 connectors on the bottom of the board. Put a 1x2 connector on the top and short it (or not) with a shorting jumper depending on whether you want to share power between the two badges or not.

This is an adapter to convert an SPI based (AVR ISP) programmer so that it can perform PDI programming. The two resistors are both 220Ω. The adapter connects both MOSI and MISO (each through a resistor) to PDI_DATA, SCK to PDI_CLOCK/!RESET, and Vcc and Ground on both ends. The programmer’s !RESET pin is not connected.

Note that the programmer will likely require a firmware update as well as additional support added to avrdude for this to work properly.