Garage Door Opener Sensor Reverse Engineer and Explanation

Garage Door Opener Sensor Reverse Engineer and Explanation
In this video I look at an infrared beam garage door sensor. The emitter board is analyzed to look at what kind of signal is generated. The sensor network is analyzed. The detector board is analyzed. Schematics of both are presented. These little sensors look basic but there is a lot going on.
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00:00 Introduction
00:20 Example of sensors
00:46 The sensors in operation
01:15 Current Loop Example
03:43 Detector
04:00 Emitter
05:00 Oscilloscope analysis
06:11 Detector Schematic
07:30 Emitter Schematic
09:00 Conclusion
Equipment:
Video Camera: Sony HDR-CX405
Still Camera: Cannon PowerShot SX410 lS
Lights: Two VILTROX VL-200T
Recorder: Zoom H4n set to 24-bit 48 kHz WAVE
Microphone: Shure WL183 Lavalier Microphone with windscreen
Adapter: Shure RPM400TQG
Plus a bunch of lab gear...
Website: www.allthingsoneplace.com
100 video challenge - 27%

[@jamesobrien4013]

Great explanation. I've been looking at how to get the garage door working on the shop of my new house - and there are some pretty terrible youtube videos out there (as is with pretty much any subject) Anyway, the electrical engineer in me needed a decent explanation. Well done sir.

[@AllThingsOnePlace]

Thanks! Yeah, this is certainly a little more advanced than the homeowner needs but I thought it was pretty interesting to learn myself how these work.

[@wc4r]

So helpful! This was the DETAILED info I needed.

[@AllThingsOnePlace]

Thanks for watching! I had these in a bin for years, it was fun to break it down into how it actually works.

[@benja2a]

Awesome explanation, thanks for the video!

[@AllThingsOnePlace]

Good to hear you liked it!

[@ronsparks9009]

Well explained thank you. My detectors seem to be working but they are not. They are lighted. But they are from a chamberlain and I just replaced with a Geanie. Thinking the Chaberlin not compatible with the Geanie?

[@AllThingsOnePlace]

It's a good question and I am not sure. On my actual opener there are some adjustments, potentiometers, but I never looked that close to see what they are actually for. I'm sure something would be in the user manual of the system you are using. Of course there are numerous ways to make these work, in this case the current loop, but some may use voltage sensing, or digital signaling, too many options.

[@WellsLarry]

Thank you. It was so obvious the scheme was current loop. I did not know. Now I do. I suddenly have a desire to add something in the house so that I use my garage sensors for more than stopping my garage doors, something that I might signal me should someone walk into my garage uninvited. A low resistance could easily be added in series such that a voltage could be sensed to drive something. Probably that exists.

[@AllThingsOnePlace]

I've heard of some garage door openers having the option of turning the light on when you cross the path of the beam. If security cameras didn't have motion sensing built in it could be useful for that.

[@saaront]

I have sensor/detector that looks just like yours inside. I had to get a replacement set and ordered by the same part number but the new ones don’t light up. Do the new ones run off of 6-8 volts as well?

[@AllThingsOnePlace]

These ones are really a current loop. They happen to start up at 6-8 volts but it's really a constant current supply that they operate with. So, the opener can sense the change in voltage when the beam is broken. The one side does always light up, the other side only lights up on alignment of the sensors. They're are different systems or the problem could be a break in the loop somewhere. I would try to connect them close to the opening with short pieces of wire to see if they light up. If they work there, then the issue is with the wire.

[@saaront]

@AllThingsOnePlace turns out the set I bought had miswired leads and the wiring had to be reversed. when I connected the white to white/black and vice-versa, it worked fine. Thanks!

[@nicolasloewen2226]

My dog chewed and pulled all of the wires the sensors now there to short to solder or put the wires back on the sensor. Is there anything that can bypass it that it would just always work

[@AllThingsOnePlace]

Yeah, I'd get a new set of sensors and replace the wire.

[@richardwilson117]

Where would a guy add connections that would trip a breaker when the path was broken.

[@AllThingsOnePlace]

A breaker or circuit breaker is a safety device so you'd probably not want to trip that. But it would be possible to have it control a contactor or relay to turn a device on or off. You would have to sense the current loop and switch on and off an output at some threshold. On it's own this thing wouldn't have any ability to trip a breaker.