I found some lights that I bought years ago. Four low voltage lights
with a transformer and dawn-dusk sensor. I'd like to set them up outside
but don't want them on all night. I've been trying to figure out a way
to link them to a PIR but I'm stumped. My experience of PIRs is for
mains-voltage floods and I don't know how to proceed with low-voltage
stuff. I've looked on screwfix for some ideas but can't see anything
suitable. Is it do-able?

Dougie

On Mon, 10 Jul 2006 08:07:44 +0100 someone who may be Dougie Nisbet
wrote this:-

I found some lights that I bought years ago. Four low voltage lights
with a transformer and dawn-dusk sensor. I'd like to set them up outside
but don't want them on all night. I've been trying to figure out a way
to link them to a PIR but I'm stumped. My experience of PIRs is for
mains-voltage floods and I don't know how to proceed with low-voltage
stuff. I've looked on screwfix for some ideas but can't see anything
suitable. Is it do-able?

Connecting the sensor to the higher voltage side of the transformer
might rapidly burn out bits of the sensor [1] due to inductive
loads. However, you could get the sensor to drive a suitably rated
relay, which then drives the higher voltage side of the
transformers.

The sensor is likely to be designed for being fed at 230V AC.

[1] as well as any switching device the tracks of the PCB may burn
out.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54