Are there any suppliers of such devices?
12V PIR to switch 12V lights
Jul 07, 2005
17 Replies
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1/10 the price...
After 2 duff £100+ links, how about this for £49.95?
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seems an awful lot though.
Standard intruder alarm PIR, with a 12V relay (car headlight or starter motor relay?) to switch the high-current load.
An intruder alarm PIR probably won't switch the load directly.
Owain
Can you not just use a mains PIR to switch the 12V transformer?
Intruder alarm PIR will only latch on for a second or two. You would probably need some extra logic to latch on for a reasonable time period. Also, might want some logic to prevent it operating unless it's dark.
No mains available without digging up 100ft of garden, just a 12V battery which I will charge periodically.
Rob Morley wrote:
You could purchase a caravan inverter to provide 240V.
That would drain the battery very rapidly.
Christian.
You'll need to use it to drive a suitable relay, such as:
Maplin do a kit which runs off 12 volts.
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Why?
The battery capacity is the same for a given load, 12V at n amps or
240V at n/20 amps less some for the inefficiency of the inverter.MBQ
This is the problem - the inverter inefficiency. For most inverters this is highest at low loads, and especially so for cheap inverters, which can have a no-load draw of 10-20% of their total capacity.
Besides, doing this with an inverter and 240V is just plain silly - it would be much easier and cheaper to knock up a 12V system.
Because it will draw loads of current when off, unlike a 12V PIR sensor.
Christian.
Thanks for the replies - seems that there isn't an off the shelf product.
Actually I found what I wanted...
Its a R> Thanks for the replies - seems that there isn't an off the shelf > product.
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