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Comment by MalcolmDwyer | Hacker News Reader

We have a countertop ice maker that gets jammed up and overloaded with ice on sunny days for a similar reason.

There's an infrared beam and sensor. When the ice tray is full, it is supposed to block the beam, and then the machine stops making ice.

On a sunny day, there's enough bright light in our kitchen to fool the sensor so it keeps making ice.

We have a random magazine that we put on top of it to make it work correctly.

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I have a garage door that will not close on sunny days.

Same sort of problem. The obstruction sensor at the bottom of the door is confused by the strong sunlight and the door stops closing part way and re-opens.

I've tried a toilet-paper tube around the sensor but that isn't always successful. I really wish there was a laser sensor to replace it with.

The sad thing is there are certain IR wavelengths that are a lot less affected by the sun and nobody bothered to check for an outdoor product...

The garage door obstruction sensors are located inside the garage, so it technically might be an indoor product.

Although, the possibility of a garage being oriented such that the sunlight would directly hit the sensors while the garage door is open seems like it could be a not infrequent occurrence.

Maybe experiment with filters.

Also it could be 'fun' to swap out the LEDs?

Similar problem toilet-paper hack worked.

I have this exact problem and (mostly) fixed it by swapping the sensor and transmitter. I just cut the wires and spliced with electrical tape. Now the problem still happens but only sometimes in the fall and spring when the sun's angle is just right. This is with a west facing garage about 41°N latitude USA.

But yeah, why this isn't laser based, or using a light frequency that is less affected by sunlight? Probably cost, or ignorance.

It varies by brand- some brands are better at filtering out sunlight than others. The home builder should know not to use certain brands in garages that face the sun... but they often don't.

It'a not laser based so the sensors don't have to be perfectly aligned. Keeps your garage door working when you kid knocks it with their foot.

What sucks is those sensors are designed so you can't just jump a wire to permanently defeat them.

You can, however, tape the sender and receiver together.

Very basic engineering would be to modulate the sender at a specific frequency

Paint your garage floor black: less light will reflect.

It also is a lot easier to see fallen bolts and shit on a black floor than on a white/gray one.

Is it a Genie system? My old Genie system had that exact same problem. Even making large sun shields out of Amazon boxes didn't fix it.

I had to replace my opener and door anyway and had a conversation with a tech about it. We decided on a LiftMaster in part because their sensors are very good at dealing with sunlight.

Depending on the orientation of your garage door, exchanging the sensor could put it in an unaffected position.

It looks like an industrial photoelectric sensor, including laser based ones run around $100, so maybe that can be a realistic swap.

https://www.automationdirect.com/adc/shopping/catalog/sensor...

I had a VCR back in the day that refused to function if you opened its case. It turned out that instead of using physical switches inside it used pairs of lights and detectors that would give false positive results when ambient light shined on them.

as in an optocoupler? Those are the coolest, especially for dealing with different voltages.

No, there's not any call for high voltages in a VCR, outside the feedback loop of a SMPS if it's fancy. The most common thing to use light sensors is just detecting the difference between tape and clear leader at the ends of the tape (or broken tape).

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