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Dual motion sensor circuit - questions

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New Member
Hi, first time poster here and electronics beginner. I wonder if anyone can answer a question or two few ...

As a follow-up to this post: the gentleman wanted to create a circuit to control a strip of LEDs along his driveway using a motion sensor at both ends. I have been looking for advice on doing exactly the same thing and found the conversation in his post very helpful.

I've been fascinated by electronics for a very long time (my most-remembered Christmas present was a Radio Shack 100-in-one Electronic Project kit) and years ago I attempted a project that I never finished. This left me with a number of components and I wonder if some diodes (I think) from that project would work for this project.

1. Can anyone identify whether a) the two photographs are diodes; and b) whether they can substitute in the circuit diagram from the other post, for the 1N4148 or 1N4008 (?) diode? These were purchased about 20 years ago but have never been used.
1a. First photo, the barrel says: EC9705 / .10 ±1% / 50VDC / 9039.
1b. Second photo, the barrel says: 150D / ±10% / 1 uf / 35DC / a 2 in a circle (visible just above the 150D in the photo) and 9019. You can see the "+" at the right side - this appears twice on that side.

My circuit will be powered by a 12 volt / 3 amp-hour battery running into the 12v motion detectors, as in the diagram.

2. I have read that there are two popular kinds of motion sensors: PIR (heat) sensitive and Doppler radio-wave. A post elsewhere said that for detecting a vehicle the Doppler would be better. Is that correct, or will any vehicle have enough of a heat signature to trigger a PIR sensor? PIR sensors seem to be far more common.

3. In that circuit the two detectors are in parallel so either can trigger the diodes. Like the other poster, I'll use a detector with a timer built in so the circuit will stay live for about 2 minutes. In that time, the second sensor will also trigger, 100% of the time. Will that present a problem?

Having read through the other two threads I've already learned a lot - thanks all in advance for any advice you can provide.



Super Moderator
Most Helpful Member
Welcome to ETO.

1 Your "diodes" look like capacitors.

2 I don't know.

3 It will not be a problem.



New Member
JimB, thanks for the very quick response.

I have found the 1N4001 diodes recommended so will buy some.

I found this motion sensor: 12v, 5-100w load power.

I found this relay, a Tyco .OMIH-SS112LM. Will it suit?

If not, anyone have a recommendation for the sensors and relay?

I think that with the relay question answered I will be ready to go.

Thanks again.
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