Ian Norton

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Presence sensors again!

In my previous two posts I’ve talked about hacking cheap presence sensors to work on 24v DC rather than mains. This post looks at a seemingly identical sensor with different PCB.

Component side of PIR PCB marked up 24v

As does happen with these things, we’ve ended up with another different style of sensor from the same supplier!

Solder side of PIR PCB with overlaid components in red

The design of this one is actually more complicated than we’ve seen previously making use of zenner diodes to drop the +24v DC to 5v for the front panel PCB.

Component side of PIR PCB marked up 24v

Thanks once again to Malc who eventually gave up trying to make this design work and posted me three up to look at, I shall enjoy the beer on you mate

Hack on!