LDR Sensor Calibration

Hello everyone,

I am developing a Solar Tracking device, at the moment only from East to West.

My problem is that I am using 2 LDRs on east/west side of a solar panel and one of them (the east one) always has a much higher output than the other one. (an error of about 20 to 40 in analog readings)

I have tried using the Calibration method provided by arduino, where I map the values from 0 and 255 based on min and max thresholds, and it helped a little.

What I'm using: Arduino UNO + Motor Shield for driving a stepper motor 1k Resistors in series with each LDR Analog Pin 4/5 for the readings

Anyone can suggest a way to minimze the error between the 2 LDR outputs?

Thank you, Vlad

Make the 'signal' bigger. Put a divider between the two sensors so that one is in the shade when you want it to move. Then the code can ignore small differences like 20 or 40.

MorganS: Make the 'signal' bigger. Put a divider between the two sensors so that one is in the shade when you want it to move. Then the code can ignore small differences like 20 or 40.

Thank you very much for the reply.

My Project's idea is to measure solar panel output, so a divider between the sensors would mean shading the solar panel too.

To decide when to move, I compare the outputs and if there's a difference of my choice between them it'll move.

Maybe I could simulate the 'shading' by increasing that difference?

Also, would it be better to take the LDRs off the panel and make a separate 'device' only for tracking light, with a shader between as you suggested. (I have observed that once there's more light from the east the panel starts moving to east, thus causing the east LDR to get even more light)

I have actually changed the sensors and it's all working ok.

Thank you