I would like to have a motion activated IR LED array. I found simple instructions to make a battery operated IR light which would be installed outdoors, but how can I make it respond to motion? I have a motion sensing transmitter and receiver set model #HS3600. Is there a way to make it work with the LED array? Simple instructions for a novice would be really appreciated.

  • \$\begingroup\$ So what are you asking about, how to sense motion or how to light a array of IR LEDs? \$\endgroup\$ – Olin Lathrop Jun 10 '11 at 17:12
  • \$\begingroup\$ @Olin - I think he needs help connecting the two. \$\endgroup\$ – stevenvh Jun 11 '11 at 7:03

Your PIR sensor (Passive InfraRed, that's what your HS3600 is) contains a photodetector which controls a relay (or, more likely, a triac). The photodetector is likely to have 3 connections: GND, Vcc and signal out. Signal out is a logical signal which (via a few extra parts for the delay) controls the relay. The relay is probably directly connected to the mains. You have two options:

1) either disconnect the relay from the mains and use it to switch the batteries of your IR light, (doesn't work if it's a triac instead of a relay),
2) or use a transistor to switch the batteries, and drive the transistor from the relay's control.

the whole circuit will be live, that is directly connected to the mains!

  • \$\begingroup\$ Thanks, I will open up the receiver to see what's inside. \$\endgroup\$ – frank Jun 11 '11 at 15:11


I will assume that you are envisioning a NON-PORTABLE system.

You have 3 of 4 blocks of the system:

1.) A battery operated IR booster with a manual ON/OFF switch; 2.) An AC-powered motion sensor with link to remote switch; 3.) An AC-powered remote switch, which switches AC power.

4.) The only block you are missing is a way to use the AC output of the remote switch to power your IR booster. To do this, simply purchase an AC-to-DC transformer with 9V DC output. I imagine that 500mA output would be plenty, but check the specs on one of the LEDs to be certain. (If is says, say, 100mA; then 100mA total is all you need to drive all five LEDs, since they are wired in series.)

Wire the DC output of the transformer to the battery leads of the box (pay attention to polarity, and remove the battery). Leave the LED box switch in the ON position. When the motion detector fires, it will activate the remote AC switch. The transformer will become powered, providing endless DC power to keep your LEDs fired up.


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