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Author Topic: LDR monitoring from breadboard  (Read 574 times)
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Hi guys, currently got an arduino on a breadboard, hooked up to an LDR, which will click a relay once the light level goes above the threshold value for a preset amount of time, and click it off once it goes back below the threshold.

My issue is essentially trying to get a reliable threshold value from the LDR, ie, how can I connect the LDR to another arduino board while keeping the LDR part of the breadboard circuit, as I don't want to remove it in case the actual circuit wiring affects the reading of the LDR when I plug it back in.

So, how do I go about monitoring the sensor from another arduino while keeping it part of the circuit?

Many thanks!
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An analog input should be high enough impedance it won't cause you problems - though I don't see the need to use a second board to track it - the first Arduino can Serial.print() values so you can see what's going on?  A multimeter would be handy for looking at voltages too.
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It's not causing me problems as such, i'm just trying to get the same value going to both boards, so I know for certain what my threshold needs to be. I need to plug a second arduino into the standalone arduino in such a way that it reads the exact same value that the standalone would be reading.

As for the multimeter, I have one, but how would I translate the voltage readings into the analogue values the arduino would read from it?

Cheers smiley
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