Laser fence/ trap with sonoff

Hardware
1

I am trying to figure out how to make a laser fence, that I’m both able to switch to on/off and also trigger a switch if something breaks the laserbeam.

I am planning to use the following:

  • Laserbeam like with a NO and NC output
  • Low current Sonoff with Tasmota
  • Sonoff basic with Tasmota

My concept looks like this:

IMG_0532
IMG_05321745×913 103 KB

Qustions:

  1. Does the concept seem like it would work?
  2. Is there an easier way to do this, e.g. with only one Sonoff?
  3. What should I connect the output (NO or NC) from the laserbeam to in the Sonoff, so it triggers the sonoff?
2

I think what you are looking for is a “dry” relay - in that you are not expecting voltage on the NO or NC contact, but want to know when there’s continuity, you’ll need some sort of ground as well which will probably need to be common between the Sonoff’s

Can you take a picture of the Sonoff units you are using with the associated pins available?

3

What distance are you trying to cover?
As in the detection range.

4

I have almost the same concept already running for a security beam for my windows.

I use a nodemcu as the comm device and controller. It is connected to the output of a effector 01d100 laser. The laser and nodemcu are powered by a standard 24v wall wart power supply that needs to be reduced to 3.3v for the nodemcu using a buck voltage regulator.

The laser is pretty expensive but it was the only thing i could find that had what I needed at the time. If you have a source for a different laser system that’s cheaper and can still supply the correct outputs that would be good info to have.

If you need any more details let me know.

5

If you only want to detect smallish spans say your driveway or the opening to your Garage I would look into using a TOF (Time of Flight) Sensor. You can get ones such as the VL53L1X which can cover a span up to 4M. So would be idle for most single drives.

They are only about £13 to buy and you don’t need a receiver at the other end which simplifies the install. Would be ideal with an ESP board.

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