USB Thermometer PLUS started out as an 'Arduino Pro Mini - like' board with the analog goodies that make analog readings meaningful. It was just supposed to be good at being a thermometer that used the USB-as-a-COM-port for getting requests and sending back answers.
Then we saw there was room in the case to bring out the ports to board-edge pads.
Then it seemed a shame to have that massive '328/16MHz' brain only responding to requests for temperature readings. Yes, you can easily load your own program in with the Arduino IDE, but if it's going to come preloaded with something, why not something a little more?
This puppy now takes quick, simple commands to turn pins high/low, read pins, read milliVolts and set PWM duty cycles.
SEND it an 'A0' and get back the milliVolts from Analog port 0.
After that - send just another pin number (0-7) and get the milliVolts on that pin - fast.
The same thing goes for digital pin manipulations.
Default baud rate is set to 57600.