"Reverse" motion detector timer switch

Discussion in 'General Electronics Chat' started by erogue, Nov 8, 2012.

  1. erogue

    Thread Starter New Member

    Nov 8, 2012

    This is a general question about a type of device I am wondering exists. Google searching hasn't turned up anything although I am not completely sure how to describe it.

    It stems from the local Police Anti-Burglary scheme that resulted in us being given a on/off timer switch for use when we are away to simulate being in. No surprises there, had a couple of them already.

    It got me thinking though - what I really need is a timer switch with 7 days of settings, perhaps with a random offset coupled with a motion detector that keeps the timer switch off if motion is detected.

    Therefore, if we are home and moving around the switch stays off (and therefore the light attached to it) but if we are out for the evening it comes on.

    I'm thinking the motion detector part would have to be 'different' to the one in our garden. I'd want it to have a longer memory for seeing movement than 'just now', say 1 hour. So if it hasn't seen any movement in the last hour and the timer is due to fire then the light would come on.

    Similarly if it detects movement during the period the timer is meant to be on it would go off until the next cycle.

    Obviously this is me making up exactly how I think it would work and I'm not sure we wouldn't get the odd misfire but I'd just unplug the timer if I knew we were likely to be home most of the time.

    I also realise I am disabling a lamp but I have a spare LED light strip that I could position behind the sofa that is bright enough to work even is partially hidden.

    Does such a device exist?

    I like the idea of automating my anti-burglary timer as I often forget to set up a switch to right when we are due to leave, then I can't find it/remember how it works, etc!

    Apologies if this wasn't the right place for this discussion but it struck me as a fairly specialised query for something I think lots of people might like!


  2. SPQR


    Nov 4, 2011
    HERE is a motion sensor that outputs a pulse when it senses motion.

    HERE is a timer that turns something on or off with a pulse or a pause.

    I'll bet you can Kludge something together with these.

    But let's wait for other ideas.
  3. gerty

    AAC Fanatic!

    Aug 30, 2007
    This is what some people are using now:

    It's a controller for a sprinkler system. It gives you 6 different zones with 24/7 timing, programmable for your needs. I didn't check this one specifically but most are 24v ac output, to which you would connect a relay to switch your 120v devices. This one is just an example, there are many others.
    A motion detector would/could be connected in parallel with one of the outputs.
  4. erogue

    Thread Starter New Member

    Nov 8, 2012

    Thanks for those suggestions.

    Given my lack of electrical wiring skills and a distinct fear of making something that is then plugged into the mains specifically for when we are not around I guess I was hoping for a 'product'.

    Probably a forlorn hope!

    I am in the UK btw, so it be compatible with a 240V supply. Just to make it a bit harder ...