Nodes are supposed to be equipped with:
- RF transceiver
- 4 buttons, labelled with digits, letters, colours (probably red / blue / green / yelow) and symbols (playstation style?)
- a LED for each button in matching colour
- an RGB LED
- a buzzer
- a 1-wire interface for authentication buttons (iButton)
For ease of development, they also get a serial interface ("FTDI cable" -- power supply + RX/TX + reset, also for flashing using a boot loader).
Both for development and for the final version (as far as we know now), an ATMega328 is used; for development, encased in an Arduino, which also binds the RX/TX pins to a USB serial interface.
As an RF module, RFM12B is used.
The wiring is defined in an eagle file in the project repository.
A little very unprofessional test showed that with the current configuration (through-hole mounted RFM12B with the wire antennae bent to the opposite direction of the pins) with a sender at the whateverlab solder stations a receiver starts losing 6-long packets some steps outside the metalab door front and in the library. Even without further optimization, that should be sufficient for typical class rooms.
Experiments showed that sending a login packet takes about 10ms.