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The buttons are controlled by a microcontroller (8 bit)
PIC (16F876). This processor charges a Capacitance and let it discharge
through a Resistor. When we touch the pin with a finger the discharge
is occuring a little bit slower than normally. The processor can detect
that and know if someone is touching the pin. The processor is also driving
two pair of leds (Blue and Red/Green) that can blink or stay on.
The processor communicate with the Host PC through a RS232
line at 57600 bauds
The PC can then program differents behaviours during question and answers
(Leds).
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