I am fighting a problem of unstable readings on an analog input for more than a year now… I am measuring the resistance of a light sensitive resistor. The reading is changing a lot, what reasons could there be?
The Arduino is running a solar steam system (http://www.cocinasolarmexico.com.mx/crbst_6.html), it measures illumination, a pT1000, the battery voltage, a potentiometer and a few switches, pilots a motor and a pump (via MOSFETs) and indicates temperature and voltage by a LED bar.
I guessed it was some voltage coming back from the motor when it stops and put a diode between + and - of the motor voltage and another one in the power line to protect from that. → no change.
I measure 10 times and wait 100ms in between. → not much change.
Can it be too much current flowing from the Arduino or would that just blow a fuse?
Please give me ideas where to look at…
Thanks a lot, Papillonsoleil