Jesse's Hunting > Game Cams > Homebrew Cams > How to Modify the Mainstay WM2 (aka Regent MS20W, MS20C and MS20B) PIR Motion Detector Spotlight Units

How to Modify the Mainstay WM2 (aka Regent MS20W, MS20C and MS20B) PIR Motion Detector Spotlight Units

A motion sensor you can use is the one made by Regent for a driveway motion spotlight. Regent part # MS20W, MS20C or MS20B is $7.95 at Wal-Mart. This PIR motion sensor needs 120 vac to work in normal use, but we can modify it to run off 5 to 12 vdc. This PIR unit draws 1 .5 milliamps while idle and 12.7 milliamps when tripped at a battery voltage of 9. 5 vdc. You can get the 9 volt battery lead wire pigtails at Radio Shack or any electronics store. I now have the 9vdc Radio Shack PIR sensor (part # 49-425), modification plans posted. This sensor uses 12X less power than the Regent MS20 sensor and is easy to modify. $24.95. It took me approximately 20 minutes to modify the sensor.

NOTE: Regent has been sold to Cooper Lighting and these motion sensor lights now have a Cooper Lighting on the box. 4/15/01 from Swampfoot. I was at a Walmart the other day in N.C. and I saw a sensor called "Mainstay" model WM2, it was in a light green and white box sitting right next to the Regent MS20's, same specs, 110 degree coverage, 70 foot range etc. same price $8.94 and it was made by Cooper Lighting. This is the new Regent MS20 just packaged different.

PLEASE, PLEASE, don't buy another brand or model of motion sensor and try to make the modifications I have listed below work. The electronic circuit boards in these motion sensors are NOT the same. I'm sorry, but I just don't have the time to figure out every PIR on the market nor answer questions about why the PIR you bought won't work. For some reason the PIRs with sensitivity adjustment are tough to modify, several of us have tried to figure them out and no luck so far.

To take the PIR motion sensor off the spotlight unit, remove the screw that holds the motion sensor together and pop the motion sensor housing off the stem from the spotlight housing. Cut the red, white and black wires by the wire nuts in the spotlight housing and pull them through the stem, which will remove the whole motion sensor from the spotlight housing completely.

"Blackwater" has an excellent blow by blow tutorial with pics on how to take the Regent MS20 apart here.

Pry the top off the PIR sensor housing. Gently pull the PIR electronic circuit board out of the housing, it's wedged in pretty tight but it will come out with enough yanking. Make a note of how the plastic piece that sits between the PIR board and the white fresnal lens is installed. It has to go back in the same way by laying it on top of the circuit board and then inserting both together into the PIR motion sensor housing. Also note that the fresnal lens in the front of the motion sensor unit has different zones in it's design. The longer vertical zones go on top.

DO NOT plug this board into 120 vac while you have it out or at any time, you can be shocked by the voltage. To modify the circuit board to run off 5 vdc to 14 vdc instead of 120 vac you need to cut R3 out or just break the connection as shown in the diagram. Leave the "Test/Auto" switch in the "Test " position for a 4 second relay time on with detected motion. If you leave it in the "Auto" position the sensor will only work at night. The motion sensor will reset after 4 seconds and will trip again only with detected motion.

Turn the board over and solder the red positive dc battery wire lead to the spot shown in the diagram on the right. If you need to learn how to solder, click here. Remove the white wire on the board and solder your negative black dc battery wire in the same hole as the white wire came out of. Unsolder the blue 24 vdc relay that comes with the Regent PIR board according to the circuit board pic.

Somebody mentioned awhile back that he had trouble finding relays to fit the existing holes in the MS20. When I have trouble like this, I solder in some short wires where the old relay was then turn the relay upside down and glue it on the PC board and solder the wires to the proper relay terminals.

Solder the 9 vdc Radio Shack relay in the same holes you just took the other relay out of. One lead of the Radio Shack relay is not used, you'll see which lead when you line up the holes, cut the unused leg off flush on the bottom of the relay. IF you are using a different battery source than 9 vdc, hook up the relay that works with you battery power.

12 vdc relay for 12 vdc battery etc. Hook up your batteries, the relay will click on and the PIR unit takes about 15 to 30 seconds to initialize, then the relay will click off. Test the unit by moving your hand in front of it, you should hear the relay click on. If you wiggle the board even without having your hand in front of the sensor it will trip, so hold the board steady or lay it down and then move your hand in front of it.

RED LED WALK TEST LIGHT - Radio Shack part # 276-270 at $1.99 each. 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 on the right to wire the LED to the Regent PIR sensor board. This LED already has the resistor inside the case so you just have to solder in the 2 wires. The black wire goes to negative and the red wire goes to pin #14 on the IC of the Regent MS circuit board. 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.

Put the PIR sensor circuit board and white plastic piece back in the housing making sure to line the board up with the rails inside the housing. The wires will fit on the slot cut into the top piece of the sensor unit. There are two more things to do to get the sensor ready. This sensor has a 70 foot range but the detection view is 110 degrees across the front from left to right.

The diagram to the right shows how the Regent MS20 PIR beam looks from the top and from the side. If you get just the heads or tails of animals you can take some tape and cover the left and right sides of the white fresnel lens that sits in front of the sensor board to narrow the PIR sensor beam a bit to get the animals more in front of the camera when it trips. Leave about a 1 1/2" wide opening for the beam. The Canon Owl camera has a 1/ 1/4 second delay when it has been turned on for awhile so you cannot narrow the PIR beam too far or the animal will be out of the field of view of the camera by the time the camera shutter fires.

One way to compensate for the camera shutter delay is too move the camera back off the trail more to widen the camera's field of view. You can test this by taking your camera out of the housing and looking through the viewfinder to see how wide the field of view is for the camera. You can also tape off the two lower grids of the fresnal lens if you don't want to pick up small animals like rabbits or squirrels. This will leave just the longer range beam and you'll have to walk test it to make sure it is aimed where you want it.

The PIR sensor works by detecting an IR (Infrared), change between two zones or fingers of the fresnal lens, so you must have movement between two zones to trip the sensor. If you just stand in one spot and wave your hand it may not trip the sensor since you're not breaking two beams or fingers. It may take moving a couple of feet when you're out at 20 feet from the sensor. Up close it may just take a hand wave since the fingers or beams are closer together.

When you put the fresnal lens back in make sure the longer vertical parts of the fresnal lens are on top. You can turn the fresnal lens upside down if you want to experiment on a different coverage of the PIR beam. One last thing is the housing has a opening around the switch, you can seal this opening with RTV silicone sealant or hot glue to prevent any moisture from getting in. You might also want to seal around the white lens also, just don't get the silicone or glue all over the lens. If you want to mount the fresnal lens flat and the PIR sensor without the housing and completely inside your camera housing, you have to keep a 1 1/16" distance from the sensor to the fresnal lens.

TIMER CIRCUIT - if you have your cam on a feeder or bait pile or you don't want pics taken in real short periods of time you can cover (tape or paint) the light sensing Cds resistor and set the "Test/Auto" switch to auto. This will give you about a 2 minute delay because the auto position holds your relay closed for the whole time period. One problem has been reported with this setup. Some units will take 3 minutes to reset in "Auto" mode and this causes the camera to lock up and you'll need to turn it off, than on, to get it to take a pic again. Test it out before you set the cam in the woods and if you have this problem, use a dedicated timer board explained below.

If you don't want to have the relay closed for long periods of time you'll need to buy a timer kit or 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 Regent MS 20 relay 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.

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.

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

You can also 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. The only drawback to this timer is it uses 5 mA for power so you'll need a beefy battery like a gel-cell with some capacity to get several weeks of use.

FOR THE TINKERERS - If you want to tinker with the Regent MS20 PIR circuit board 4 second "Test" timing, Kevin helped figure out the following. R25 and C13 (22 uf), values determine the time of the relay closure when the switch is in the "Test" position. To gain a specific delay time, a multi-position switch with specific resistors would work best, but he simply used a 470µF capacitor and a 1M potentiometer. It is a little touchy to get a specific time (especially times < 1 min), but it works for up to a 12 minute delay. Thanks Kevin.

Tinhorn has done some tinkering with the timing and his testing shows R25 is the timing resistor for "Auto" which includes the light sensor, and R26 is the timing for "Test".

The IC is a LM324N which is a quad op-amp. Pin #14 of the IC goes high when the PIR is tripped, which causes Q4 to forward bias, putting a ground on the relay coil, closing the relay.

This PIR sensor will operate 24 hours continuously unless you install a photo sensor switch circuit to have the option of daytime operation only. 2 regular alkaline 9 vdc batteries wired in parallel should last about a 4 to 5 days or 10 pics . Rechargeable Ni-Cad 9 volt batteries are only 120 mah capacity and won't last very long.

If you want to use a 12 vdc car battery, 12 vdc Makita cordless tool battery or 12 vdc gel-cell battery for longer battery life, hook up the camera and Regent MS20W sensor according to the 12 vdc battery schematic.

SOLAR POWER - You can also add a solar panel 12 vdc battery charger to extend the battery life. Cabela's has the solar panel chargers that put out 80 milliamps of charging power for $19.95 and a 7 amp/hour gel-cell battery for $26.99. Cabela's also has a wall 120 vac charger to charge the gel-cell batteries. You can get smaller gel-cell batteries at Powersonic Batteries. A 1.2 amp/hour gel cell battery will last about 5 to 6 weeks with a full charge. How big a battery you need depends on how often you can check the camera.

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