Dr Skip wrote:
> I am considering a project whereby a lot of
> PICs/Arduinos/RaspberryPi(0,2,3)/others monitor various AC (120v,
> maybe 240v) lines and log their state. Because of the qty and low
> budget, I need the absolutely lowest cost and simplest way to do this,
> bearing in mind protection of the processor circuits. This isn't for
> resale, so extreme idiot-proofing isn't needed, just reasonable
> protection of the electronics involved.
>=20
When I wanted to monitor 4 central heating circuits (240v) I used panel=20
mounting neons inside a black plastic box. Attached to each neon lamp=20
via a piece of black tubing were 4 LDRs. Each LDR had a pullup resistor=20
with the junction fed to an ADC input on an TinyAVR 8 pin chip.
The AVR was programmed to simulate the obsolete DS2450 4-input 1wire chip.

A remote arduino (also collecting various 1wire temperature sensor=20
readings) took the ADC values and decided if the neon was on or off.

George smith

--=20
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