Two Motion Sensors To Control Three Lights

[william.and.dori]

Would like to use two motion sensors (the ones sold individually and not connected to any lights) to turn on three flood lights. The idea would be if either motion sensor was tripped the three lights would go on.

My thought was to connect the switched side of the one motion sensor to the three lights and to the switched side of the other motion sensor. So it would be:

(Hot Wire) (Switched Wire)(Switched Wire)(Switched Wire)(Switched Wire)(Hot Wire)

My concern is that the current applied to the motion sensor that is NOT activated when the other is activated may damage the motion sensor. In other words if Motion Sensor [A] is tripped it would allow current to flow to all three lights and the switched side of Motion Sensor [B]... would that damage Sensor [B]?

Thanks, William

[Scott]

There are a couple of ways this can be done...

If you want to go totally geek, using a relay and two triacs would be the easiest.

Have the sensors wired up so that each one is connected to its hot, and the other side connects to the G on the triac. The other terminals of the triac go to a relay and thier hot side. The relay is energized when either Triac is turned on. You could omit the relay, but my guess is that the current for three of them may be too much for just the triacs.

If you havne't done electronics, just google TRIAC and you should find more than enough. You could also check out a local electronics trade school and have one of the students take on a project.

You could use relays by themselves, depending on what kind you find, each sensors could be hooked up to a relay, and the outputs of both relays could be connected in parallel which supplies the flood lamps. Just make sure the Voltage and Current are enough.

Finially, I beleive that there may still be X-10 type gadgets that also do this though it has been awhile that I have looked into it.

I wouldn't wire it up the way you are proposing without have specifics as to the sensors etc...

Finially, if you aren't familiar with electricity, don't do it yourself.

Hope this helps...

-Scott

[RBM]

Simply wire the two sensors in parallel. Hot to black wire of both sensors, white to white of both sensors and white to lights, and red from both sensors to black of lights. Whichever sensor picks up motion activates, and yes it backfeeds the red load wire of the other sensor, which does nothing because it's relay is open. If they're both activated, they'll both time out normally. The one thing you can't do is feed the sensors from separate power supplies

[ransley]

ut

Wouldnt you blow the circuit if both trip, you will be feeding 120 to itself. X10 has remote units that can trigger many lights, when I pull in the garage 4 sensors go off, with 15 lights, the garage sensor triggers 3 more through a code that goes through the AC lines. one in garage, two outside, one inside, and 3 button garage remote are compatable. X10 also has battery powered RF sensors and interior keypads and a computer program it sells. Cheap home automation.

[RBM]

All these devices have wattage limitations. Garden variety motion detectors are 300 to 500 watt. There are others available with higher switching capacities as well. If you wanted to control lighting from multiple circuits or higher wattages than the motion detector is capable of, you'd need to use relays or line carriers to do it, but I would always opt for simplicity if possible

Wouldnt you blow the circuit if both trip, you will be feeding 120 to itself. X10 has remote units that can trigger many lights, when I pull in the garage 4 sensors go off, with 15 lights, the garage sensor triggers 3 more through a code that goes through the AC lines. one in garage, two outside, one inside, and 3 button garage remote are compatable. X10 also has battery powered RF sensors and interior keypads and a computer program it sells. Cheap home automation.

[RBM]

Wouldnt you blow the circuit if both trip, you will be feeding 120 to itself.

This is why you must use the same feed to both motion detectors. In the event that you used a leg of different potential, you'd blow the detector

X10 has remote units that can trigger many lights, when I pull in the garage 4 sensors go off, with 15 lights, the garage sensor triggers 3 more through a code that goes through the AC lines. one in garage, two outside, one inside, and 3 button garage remote are compatable. X10 also has battery powered RF sensors and interior keypads and a computer program it sells. Cheap home automation.

[hallerb]

relay would be easier safer and more reliable

[RBM]

Based on?

[gfretwell]

I am doing it with no problems. Just be sure your total light load is within the spec of the detectors.

[Bob F]

Make sure they are on the same phase of the power. Preferably, they should both be on the same circuit. If the sensors have relay outputs (click when operated) I can imagine no problem.

[sachintanwar21]

hello mate hope you reply asap I have connected 6 motion sensor to 5 lights just wondering where to put a relay to get the best result. I am connecting sensors in parallel

[gfretwell]

There are plenty of motion heads that have a relay output

[Bob da Builda]

On Thursday, January 31, 2008 at 11:21:10 PM UTC-5, [e-mail] w rote:

I know this is an old post, but maybe someone could help me. I have a 1000' driveway that I want to light all the way down. I have power at both ends and would like to use both power supplies so as to keep the w ire size to a minimum. I would need multiple motion sensors, at least one a t each end of each circuit to light the drive. I would really prefer that a ll lights engage when any motion sensor is activated, but know that I can o nly run sensors off of one circuit in parallel. My thinking is to use relay s, but I am not familiar with relay wiring, particularly with using multipl e circuits. Any help?? All is appreciated!!

[Ralph Mowery]

motion sensor is activated, but know that I can only run sensors off of one circuit in parallel. My thinking is to use relays, but I am not familiar with relay wiring, particularly with using multiple circuits.

Iknow this is going to be past you also, but seems like a good way to use an Arduino UNO. It is a microprocessor that can be bought from China for less than $ 10. You would need that an a relay board that the relay board only goes from the 5 volt circuit of the Arduino to the line voltage to activate the lights. You could have around 5 or maybe a few more sensors or switches if you want.

[gfretwell]

You can use a 120v relay or, if these are mostly LED bulbs (total less than 300w or whatever the sensors are rated for) you can connect them all in parallel. I am using paralleled sensors in 3 different places here with no problems. (the Heath/Zenith ones) The relay style work with all LED/CFL but if they are electronic switching, you need one incandescent bulb in there to give it a resistive load. An 11w sign bulb is usually enough.

If you do go with a relay or two, connect the 120v coils to the red (switched wire) and connect the black (hot) wire through the relay points to the string of bulbs. Just be sure all of the detectors are connected to the same circuit from the panel.