electronic timer

Discussion in 'General Electronics Chat' started by lostit, Sep 6, 2009.

  1. lostit

    Thread Starter New Member

    Sep 6, 2009
    Hi all,
    Newbie here looking for some help. I have very limited knowledge in electronics and hoping to learn a little more. I have recently been given a security camera to play about with, it is a camera powered by mains 220v and has an IR sensor which when activated starts the camera for a period of time which can be viewed on a tv.
    What i want to do is find out how the timer is working and could i disable it so that the camera will be on all the time. I searched the forum and web but dont really know what type of timer i am dealing with.
    Anyway, any help would be appreciated i can also post a picture of the board if nessecary.

  2. mik3

    Senior Member

    Feb 4, 2008
    Maybe the timer can be disabled by the camera's settings.

    Do you have access to the circuit of the camera?
  3. kkazem

    Active Member

    Jul 23, 2009
    Hi lostit,

    Here is an easy fix to rid you of the timer problem. My fix won't allow you to use the timer at all, the camera will simply be on all the time.

    Take a small amount of power from the +12V DC supply that runs the camera, or if it runs on mains, you'll need a small, plug-in type of DC power supply. The exact DC voltage doesn't matter much. Obtain an IR LED (see any online supply house like Digikey, Newark, Allied, Mouser, etc). Whatever DC voltage you're using, you need to calculate the series bias resistor needed to keep the LED from damage due to overheating. R = (Vsupply - 1.3)/0.01. This will give you the resistance value in ohms. Put the resistor in series with the LED with one side of the resistor to the VSupply(+), connect the other side of the resistor to the LED ANODE. Connect the LED Cathode to the Vsupply(-). Now, all you have to do is place the LED somewhere near the IR sensor. In fact, these sensors are ususally very sensitive and it can likely be places several feet away from the camera and still work to keep the camera rolling.
    That's it.

    Good Luck,
    Kamran Kazem