I have a crude power sensing system I built with an Arduino Pro, a GPRS shield, and a relay that will send me a text message when my power goes out. The Arduino is powered from a UPS, which will keep it going after the power fails. To sense a failure, I have a relay held closed by a USB wall wart pl…

Need transistor/circuit help for building a power sensing circuit.

MarkT April 4, 2014, 11:20am 3

A UPS should have a serial interface you can use to obtain status information I believe.

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