hi,
i have a problem with my arduinoboard. i connected five photosensors at the analogin-ports. if i cover one of them (sensor1), its value decreases from about 900 (i read them over the serialport) to 0. if i cover another sensor (sensor2) then, its value decreases to 300-400. sensor1 shows about 6-7 then.
for my project i have to be shure, that their value is always (nearly) the same (uncovered/covered). whats wrong with my circuit?
thanks in advance,
hans
Greetings Hans,
The circuit you've shown should work just fine, so make sure your wiring is correct. All of the photocells should have 1 lead in common to ground and all of the resistors should have 1 lead in common to +5V and each resistor should connect to each photocell and the analog input. There should not be any crosstalk through the power or ground buses, so you shouldn't need to use the buffer amplifier approach, but that might be recommended for other reasons such as scaling or filtering. Hope that helps!
Regards,
David