To take this PIR motion sensor apart, remove the battery cover and then remove the Phillips head screw in the pic. The PIR sensor housing will now separate into 2 pieces. Pull the circuit board out and cut off the red and black wires from the speaker. Solder the black and red wires from the circuit board to your LED red and black wires. Solder in the coil wires from a 5 vdc reed relay (Radio Shack part #275-232, $2.49), one relay coil wire goes to the larger IC (integrated circuit) pin #2, the other relay coil wire goes to battery negative (black battery wire). See pic for which pin is #2. Some people have reported that using IC pin #2 sometimes doesn't trip their 5 vdc relay. If you have this problem, wire the 5 vdc relay coil to the red and black speaker wires, just like the LED. Hook the N.O. (normally open) contacts of the 5 vdc reed relay to the camera through a switch.

You can mount the 5 vdc relay outside of the PIR sensor housing and run the coil and contact wires inside the housing. I glue just the front half of the sensor housing onto my game camera unit and glue the fresnal lens in flat. This gives me quick and easy access if I need to pull the sensor board out. I then just tack some glue on the sensor board corners to keep the board in the front part of the sensor housing. Also solder a 1N4001 diode (Radio Shack #276-1101A), across the relay coil where you hooked it in at the red and black wires (see illustration) to prevent any backfeed when the relay releases. A coil of wires becomes a magnet when DC volts are applied to it. When the power is disconnected from a coil of wires, the magnetic field collapses and creates a voltage in the coil of wires who's polarity is reversed from what was applied by the battery. Electronic things are easily damaged by reversing the current. The diode grounds out this reversed current. The diode cathode (silver band side) goes to where the red wire is and the diode anode side goes to where the black wire is.

Red LED walk test light - If you want to have a red LED walk test light to use when you set up the camera to see where the detection beam is aimed, use the diagram below to wire the LED to the Radio Shack PIR sensor board. Radio Shack LED part # 276-270 at $1.99 each works good for a walk test LED. This LED already has the resistor inside the case so you just have to solder in the wires. Solder the red LED wire to the red speaker wire and then solder the black LED wire to the black speaker wire. You can use a switch to turn the red LED on and off to save battery juice. You can also use a piece of stick-on Velcro to cover the LED up when you are done like Camtrakker does on their camera unit.

You can use a DPDT switch to combine the camera on/off and LED on/off functions. Wire the switch so that when it's switched up the LED test light is on and camera is off and when your done setting up the cam and throw the switch down, the camera is switched on and the LED is off to save battery juice. Make sure you mark the switches so you know which way to throw them. All Electronics has the DPST mini toggle switches for $1.25 each. Radio Shack DPDT switches are part # 275-636 and $3.59 each. Thanks to TR for this tip.

You can reassemble the Radio Shack PIR housing and board together and cut a hole for it to look out of you game camera housing or you can just mount the PIR sensor circuit board inside the game camera housing with hot glue (see pic of Yotee's cam with the sensor mounted inside the housing). If you mount the whole housing, make sure and seal off the speaker vent holes and any other places water could get in. To mount the circuit board by itself inside the game camera housing, you'll have to remove the white fresnal lens from the PIR housing and cut a hole for the sensor to see out of. Glue the fresnal lens flat onto your housing and mount the PIR sensor board so that the PIR sensor is approximately 5/8" from the fresnal lens. The PIR sensor is the little round metal can with the window on the front of it (see pic). Make sure wherever you mount the board that you can still get to the alarm/off/chime switch. Cut the red battery lead and wire this lead to an on/off toggle switch on the outside of your housing.

When you test the PIR sensor you'll hear a faint chiming sound from the relay when the sensor is tripped if you wired the relay to the red and black speaker wires. The sound is the relay since the AC voltage is rising and falling to make the chime sound. You can surround the relay with some foam in a film canister to quiet the relay sound. It should be barely audible when in a housing. Some people like the relay click or whine sound since it makes the animal turn toward the camera. I kind of like it for that as I have many pics of animals that would be great if they were looking toward the camera and not the other way.

If the Canon Owl PF camera is set to"Auto Flash" mode, the Radio Shack 49-425 sensor will fire off 2 to 3 pics. You'll need to run the 49-425 sensor to a 555 timer like Yotee and NoLuck said they do on theirs. I run my cams with the camera flash set to "Forced Flash" (the lightning bolt showing), which means the flash fires every time, night or day. I like this for fill flash for shadows and with forced flash the Canon Owl PF takes 5 seconds to recharge the flash, by then the Radio Shack 49-425 sensor has reset and only one pic will be taken. The same for the Canon Owl camera.

If you want to use a 12 vdc gel-cell or Ni-Cad battery to power the Radio Shack #49-425 PIR you can. Sawdust tested his Radio Shack out with 12 vdc and it worked out fine. I'm not sure how much above 12 vdc you can go for a power supply, I don't have the guts to find out. Holler if you do and it doesn't vaporize.

TIMER CIRCUIT - if you have your game cam on a feeder or bait pile or you don't want pics taken in real short periods of time, you'll need to build Tinhorn's or Marty's timer circuit and hook it between your PIR sensor and the camera.

Click here for the Tinhorn's schematic of the pic timer. Use the 5 vdc reed relay you soldered in above to connect a ground to the timer input. Huge thanks goes out to the electronic Jedi Knight Tinhorn for his time in getting this circuit figured out. We are not worthy.

This timer by electronic yodas Tinhorn and Welby is an adaptation of the timer found on page 13 of the Radio Shack manual "Timer, Op Amp, & Photoelectronic Circuits & Projects" by Forrest Mims, III. This timer will prevent the cameras from automatically shutting down, which is usually caused by an animal keeping the PIR tripped for more than three minutes. What's more (and this is the best part), if you are using the MS20 sensor, you can clip the photoeye and switch the unit to "Auto" and take advantage of its time delay feature which is approximately 1.0 to 1.5 minutes. Timer by Welby and Tinhorn.

Click here from Marty's timer circuit. Thanks Marty for allowing us to use your timer.

Kevin has made some timer kits using Tinhorn's 2 stage timer that has from 2-5 seconds for the shutter closure and 0-5 minutes for the delay between pics. It will work with any PIR, too. Price is $25.00 for all the parts you solder to the etched circuit board. Kevin's email is kevinmay@bigfoot.com. If you are using a large capacity battery you can get a 2 stage pic delay timer kit for about $20.00 at Quality Kits, it's part # 8015. All you have to do is solder a few parts to the pre-etched circuit board and set what time delays you want.

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