light to motion detector

Discussion in 'The Projects Forum' started by Connect, Mar 3, 2010.

  1. Connect

    Thread Starter New Member

    Feb 24, 2010
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    Hi
    i have built an IR motion detector which has a relay (powered by 12v) in which something like an alarm or light can be attached. I want to attach a 20w 12v spotlight to the relay so that when motion is detected the light will turn on.

    I have two queries in this regard:

    1. how on earth do i connect the light source to the relay (i.e what, in addition to the light itself, is required and how is it actually connected?)

    2. i want to install this outside so would prefer to use a battery. Is that possible and practical, or will all batteries with this set up be drained to quickly?

    thanks
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    1. Use the relay as a switch.

    2. 20 watts is a draw of under 2 amps. The run time depends on the battery used.
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    Break one wire on the light cord and put the relay in line. Just like you would a light switch. (Thats what it is after all)
     
  4. Connect

    Thread Starter New Member

    Feb 24, 2010
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    thanks for the responses.

    with respect to my first point, i understand the relay is like a switch, which is why i want to use it in the set up described... im just new to electronics and was undsure as to how to literally physically wire it up with the light i.e which wire of what goes where etc. If that is too difficult a question to respond to in words, fair enough, it might be one of those things i have to see done?

    with respect to the battery, assuming the battery is a combination equalling 12 v or one of those smaller 12v batteries of really good quality and strength... just wondering if anybody knew of an approximate run time i could have with a fairly decent abttery in teh set up.

    cheers again
     
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Member pbalien73 went thru this same exercise using 2 6V lantern batteries lighting a 912 bulb @ 1A. With intermittant operation batteries only lasted about a week; converted to a 9 LED lamp.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
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    Do you already have the relay? If so, what is the part number?

    I can draw up a wiring diagram for you to follow.
     
  7. Connect

    Thread Starter New Member

    Feb 24, 2010
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  8. Connect

    Thread Starter New Member

    Feb 24, 2010
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  9. retched

    AAC Fanatic!

    Dec 5, 2009
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    Ok, Do you need further assistance in wiring? The kit should come with a detailed wiring diagram, if not, let it be known, and I'll help you out.
     
  10. Connect

    Thread Starter New Member

    Feb 24, 2010
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    Yeh thanks the kit doesn't come with any light etc and doesn't detail how to wire what you want the relay to trigger. I want to attach a light of some kind.

    The thing is I only want to operate it on battery so I can install it above my door or something without drilling holes connecting it to a power point.

    I guess I just want advice on:

    1 connecting relay to a light

    2 what light would be most feasible (globe, a bunch of LEDs etc)

    3 if I can operate by batteries alone, which batteries best suited for longer life

    Thanks so much mate
     
  11. Connect

    Thread Starter New Member

    Feb 24, 2010
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    anybody able to assist?
     
  12. retched

    AAC Fanatic!

    Dec 5, 2009
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    The on board relay is fine for what you want. So no additional is needed.

    For batteries, this runs on 12vDC so you will need a pretty decent sized battery, unless you are willing to use a voltage regulator. We could take a two - 9v batteries serial and step them down to 12vDC. That will allow some extra power for the LEDs. Now you will be replacing batteries pretty often with this type of configuration. The IR unit uses power at all times to scan the sensor for movement, then to power the relay when movement is detected, THEN the batteries have to power the LEDs that are bright enough to light what you want.

    Can I talk you into using a wall wart type plug in power adapter? You would only have to run the little 2-wire to the unit, so you could forgo drilling. It would be about the size of a cell phone charger cord.
     
  13. Connect

    Thread Starter New Member

    Feb 24, 2010
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    thanks for the response.
    Yes you can talk me into using anything at all... except, if the unit monitoring movement etc is outside, where am i supposed to run the cord from without drilling, since the power point will be inside? im not sure i completely understand what you mean? And what LED or globe set up can you recommend? any links so that i can see what it is you mean.

    Sorry i know im a pain.
     
  14. retched

    AAC Fanatic!

    Dec 5, 2009
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    You couldn't run the cord out of a window or door? What I was getting at, was, the cord would be small enough to be closed in a window or doors weatherstripping.

    As for the LED, It is really up to you, how BRIGHT you want the light.

    Do you want to just light up the door enough to put the key in the knob, or do you want to be able to clearly see someone from 20 feet away at midnight?

    If the door light is what you want, three, 1w-10mm white ultrabrights should be fine.
    If you want flood lighting, with a battery, you will wanna go with Cree or Luxors 3w Super-bright-It-will-blind-you LEDs.
     
  15. Connect

    Thread Starter New Member

    Feb 24, 2010
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    You are right. Assuming the cord of any power pack is long enough to be run from inside to the detector (i wll need it to be at least 6 metres long) then no problem. Could i put both the sensor and light in the same box and run them off the same power supply? Is the light powered seprately? i wouldnt mind a bright light, but not the brightest, justto light the immediate vicinity of the front door / porch. I picture botht he light and sensor being housed in a box (obviously with relevant holes cut for sensor to be placed and light to shine or be positioned).

    Thanks i know i am so time consuming.
     
  16. retched

    AAC Fanatic!

    Dec 5, 2009
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    No problem. The light and sensor can be run off the same supply, as long as we choose a suitable supply.

    We will start with the three - 1e LEDs. That will cost around $2. If you decide they are to dim, you can easily upgrade with a change of a resistor and the LEDs.
     
  17. Connect

    Thread Starter New Member

    Feb 24, 2010
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  18. Connect

    Thread Starter New Member

    Feb 24, 2010
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  19. retched

    AAC Fanatic!

    Dec 5, 2009
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    MP3011 will do nicely. I would check around your house to see if you have a similarly rated supply before buying. Check old electronics.
     
  20. Connect

    Thread Starter New Member

    Feb 24, 2010
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    Thanks for that. Any of the links for the lights suitable?

    I guess now that i have the appropriate power product, once i confirm the proper light that would match it all from those links i sent you, it will just be a matter of wiring it up and connecting it all and placing it in an appropriate housing?
     
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