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Topic: Lilypad Internal voltage reference (Read 2807 times) previous topic - next topic

ChrisF1

I'm using a Lilypad on 3.3V and trying to monitor the battery voltage. My thought was that I could set the voltage reference to INTERNAL (ie 1.1V), then tap off a proportion of the battery voltage (say 25% using a 100K and 300K potential divider). I always get a reading of 255, ie exactly 25% of full-scale, whatever the battery voltage. I would expect something around 750, ie 1/4 of 3.3V, referenced to 1.1V and scaled to 0-1023 range.

It seems to me that the INTERNAL reference doesn't work on the Lilypad. Has anyone else got experience of using the INTERNAL reference on Lilypads

Thanks in advance

robtillaart

have you tested with a potentio meter?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

ChrisF1

Yes I have! The battery is at 3.26 volts. Obviously I can't use the default reference, because that's derived from the battery voltage as well, so both the rererence and the battery voltage will discharge identically. My point is I'm trying to use the fixed INTERNALvoltage reference at 1.1V, but it still seems to be using the DEFAULT setting.


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