Sound activated light switching

Just bought a security light (the type that fits between the lampholder and bulb)

You leave power connected to the lamp, the lamp switches off during the day (photocell) and activates during darkness when triggered by sound.

The unit works very well, and got me thinking. I have several lights in the house that tend to me on for long periods - and would benefit from fitting sound activated switching. The problem is that all my lights are multiple units (i.e 3 lamp ceiling fitting etc) so a bulb solution is not suitable.

Is it possible to by a pre designed device (ceilng/loft mounted device) that can be wired in line so to provide the same energy saving benefits as the security lamp? If not how difficult would it be to design?

Reply to
Clive
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I don't know about sound activated units, but there are PIR's which can switch enough amps to make simple lighting circuits work. If placed in line with a photo-cell unit, then you have lights which are only active when the light level is below a set lux and would only switch on when a body is detected in the area of the PIR's. If you think this would be of some help to you, then a web search for the relevant parts may prove to be within your price range.

Reply to
BigWallop

"BigWallop" wrote | I don't know about sound activated units, but there are PIR's which can | switch enough amps to make simple lighting circuits work. If placed in line | with a photo-cell unit,

Don't most of the light switching PIRS include a photocell for night-only operation?

The Maplin BZ18U says "a built-in variable photocell deactivates the motion sensor during the day". And the Microscan unit PH41U says "automatic night-time only operation".

Owain

Reply to
Owain

No pre-designed item leaps to mind (but see later). Designing-your-own is simple, construction also pretty easy but care needed as you're working with 240V, i.e. lethal stuff: so don't do it unless you know what you're doing. The magic word is "relay" - an electrickally hoperated switch. You make the relay coil be the load of the sensor, and use the relay contacts to switch the Actual load. Depending on the characteristics of the sensor, the relay coil may not be enough of a load, in which case you'd fit the relay coil in parallel with one of the bulbs, and use its contacts to control power to the remaining bulbs. Neatness, boxing-up, integration with the fittings you have, insulation, strain relief, arrangements for isolation, etc., all left as an exercise for the reader ;-)

(I said no pre-designed item occurred. An overpriced and relatively intrusive pre-designed solution did occur, but it's overpriced and rather intrusive ;-) You could try one of those powerstrips where one socket, on detecting that the thing plugged into it is drawing current, turns power on to the other sockets (and conversely turns them off when the Controlling load is switched off). The computer add-on catalogues (Misco, for example) sell such things, for daft-to-me money (30? 40? quid), with the idea that you plug your main computer unit or monitor in as the Controlling load, so that when you turn it on, the rest of your computer installation - printer, modem, external CD-R, whatever - gets powered up. In this case you could plug a table lamp or standard lamp with the sensor in it as the Controlling load, and plug the remaining lamps in on the controlled sockets. But the cost, and the fact that the original poster had ceiling lights rather than plugged-in lamps as the intended loads, makes me consider this solution less than optimal; in fact, I'd characterise it as overpriced and relatively intrusive...)

HTH, Stefek

Reply to
stefek.zaba

What about the stuff on

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of PIR switches etc there. Not seen the website yet just their catalogue.

It also looks like the switches are adjustable to work as variable levels of lux and so will only work at night.

Adam

Reply to
ARWadsworth

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Reply to
kitchenman

A bit expensive through, bearing in mind that the sound activated device I bought only cost less than £7.00

Considering buying another and adapting it (ie removing the gubbins and fitting into a box that can be ceiling mounted)

Reply to
Clive

I think PIR would be better than sound - what happens if you are reading a book? Lights off, "ahem ahem" lights on... or read out loud... But is PIR sensitive enough to detect small movements? after all, they only detect moving bodies...

Reply to
Abdullah Eyles

You may well be right. Just that the sound system works quite well (but prob better for security rather than energy conservation as it will react to outside sounds)

Inside using a PIR would be quite simple - PIR to detect movement coupled with a relay to switch mains voltage.

Additing a photocell isnt a problem, but how do you create a delay. i.e PIR activates light switches on for 5 mins. Each time the PIR activate the timer starts again for 5 mins - after 5 mins of no activity the system switches off?

Any Ideas?

Reply to
Clive

You'd just have to get used to reading aloud....

cheers Richard

-- Richard Sampson

email me at richard at olifant d-ot co do-t uk

Reply to
RichardS

Actually there is a perfect pre designed device to turn the lights on and off. Your finger! What are these mysterious rooms that need sound to make the light come on?

Adam

Reply to
ARWadsworth

Clive -

if all you want is for the lights to come on in a room when someone enters, to turn off when there's not been activity for a while, and you don't care whether activity is detected by sound or body heat, then the prebuilt PIRs do exactly what you want. The ones built for outside use are a bit bigger physically, handle more than enough current, are very cheap to buy (7-8 quid) as they're sold in high volumes, and have an adjustable "on" delay of typicalyy 2-15 minutes - so you could end up having to flap your arms around several times an hour to keep the lights on. The official Indoor variant gets called a "room occupancy sensor", and has complementary characteristics: smaller, possibly lower current capacity, pricier (sold only for the office-energy-efficiency market, so maybe 30 quid a pop), "on" period adjustable for up to 60 mins typically.

Hope that helps... Stefek

Reply to
stefek.zaba

ROFL!

Yes, but we want to DO something. that's TOO SIMPLE!!! why do what everybody else does? I think that all in this group are like myself, we like to have that warm feeling inside "I did that..." ;)

(Also, in our sister company here, there are PIR's in the toilets... Spend too long on the job and PAT! time's up guys!!!)

Reply to
Abdullah Eyles

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