1.what are the connections 5v, SS and SA? where do they come from
2.and how are connections to be made on the sensor board?
3.i noticed that the pin 11 of lm324 which is gnd is connected to anode of LED, and got confused about polarity of photodiodes and LEDS on the board.
4.where do the four terminals marked as switch on the main board go?
5.at the bottom of the lcd data pins there are connections left open, what are they?