Improving the sensor's reliability

Garadget’s laser sensor provides the reliable reading of the door state in the wide range of environments. However there is a scenario when the sensor’s confidence level may deteriorate. This happens when there’s an ambient source of bright light closely aligned with the laser beam.

Check the Reflection value in settings section of Garadge’s user interface while its laser is pointed at the reflector. If the reading is low (below 50%), then likely there is a source of light interfering with the sensor. Distance from Garadget to the door or angle of the laser beam to the reflector are usually not the factors. The reliability of the sensor can be improved by:

  • adjusting the the Sensor Threshold down to about the half of the maximum reading in the most challenging conditions;
  • breaking the alignment by either slightly moving the source of light (when practical) or moving Garadget;
  • shielding the portion of light in the direction of the reflector. Use a small sticker directly on the source or a screen anywhere on the way to put the reflector in the shadow.

I’m attaching some pictures to show the installation. I’m definitely seeing below 50%.
Initially it was in the 10%-15%. Then went up to 25%. This morning I’m seeing 47% (not sure what changed)
The white cover is where the Genie garage door opener has it’s light bulbs, so when it’s on, it’s light there.
I’ve got some foam for a temporary base to stand the opener off from the bottom of the opener.

This first picture is from the back/underneath

This second one shows both the laser and the angle to the front door.

This third one is a side view, which shows the “light” area of the Genie opener.

This fourth picture shows the 2nd DIY device I’ve built, but pretty much mimics the first one, sans relay.
You can see the laser and pick up. Would you suggest a small “hood” to wrap around the 3 (or 4) sides of the front of the enclosure? Would that make that much difference?


In your home-grown Garadget build It looks like there’s significant distance between the laser and photo-sensor. The retro-reflector sticker sends the light right back to where it came from with very little deviation. In your case the photo-transistor may be missing most of the reflected light. Another possible factor is quality of reflector.

You can put a sheet of paper over the unit with the laser picking through the hole in the middle and observe the size and shape of reflection while in the dark room.

So the distance between the photosensor and laser should be smaller… I can fix that.
Currently they’re about an inch apart. How close together are the two in the production models?

BTW, what’s on the garage door is the reflective tape as referenced by the DIY instructions.


In factory-built Garadgets the distance between the laser and sensor is about half inch. The closer - the better.

Ambient light can also be a factor, but before working on the hood, make sure that the reading is much stronger when garage is dark. If that’s not the case, then hood will not help.

Ok will try that tonight. Will modify #2 while I’m sitting here at work :slight_smile:

Also before I forget, thanks so much for generously making this project available as a DIY project!
I’ve VERY much enjoyed building it up. I’ll recommend to my non-soldering-friends to purchase a unit,
and use mine as a demo of “well it will be more finished but work similarly…”


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FYI (to cross post)

Moving the two closer did improve things, but with a small “visor” over the two I was able to get up to >80% when the light is on. Over 90% when the light goes off.

I basically just taped it on the front of the enclosure like on a baseball cap.

I am not having any luck with the open/close detector on the factory uint.
I have the laser pointed start at the reflector and ready 3 but it reads without the reflector; door opened. What is the angle to the reelect should I use 90 degrees or something else?

May the unit is defective?

The angle doesn’t have to be very close to 90 degrees. There should be nearly no difference in 45-135 degree range.
What is the sensor reading from the settings page with and without reflective tag?

the sensor reading is alway 3 with or without the refactor.
It is also 3 if I put my finger over the sensor on the device.

I checked the sensor on each device shipped out, but things can still go bad.
@dmmc90rider please ship your unit back, I’ll repair or exchange it.

The 3 I was reading was from sensor reads, which is changeable.
The refection always reads 97% open or close.
Yesterday it alway said it was open.

Now it appear to be working, but it is dark. I’ll try tomorrow in the after noon when the sun is out like when I installed it and test it the first time.

Where is the sensor reading?

Is it possible there is to much ambient light?

Right, that value is normal and it is just the number of measurements before the conclusion is made. The reflection rate is what we’re after.

For the sensor I do the differential measurements meaning that high reflection readings so any bias such as ambient light is cancelled out. Such high reflection value is only possible if the sensor is actually seeing a lot of light from Garadget’s laser bouncing back at it. The laser must be hitting either the reflector at expected distance or some other surface just inches away.

The reflection rate should drop to near zero if you point laser at anything other than reflector more than few feet away. Can you please confirm?

Reflection stay at 97 % even if the laser is pointing to something else.

Does the value change if you cover laser or sensor holes with your finger?

No it stays at 97%,
Are there any setting I should change?

We can get on a video call, I’d like to see what’s going on. Will PM you.
It will be helpful if you could dismount the unit and bring it from the garage to your desk. If it’s attached in place with the sticker pad, then remove the M4 screw holding the mount together.

I noticed that my garadget report/status is usually correct except during afternoon time. Reading this thread it looks like there is too much ambient light on my sensor. I will check that and confirm when I go home in the evening. But I have never seen the reflection above 20 in my settings even during late evenings. But in this thread it looks like I should be getting more than 90 during night. My angle might be closer to 45 degrees. Do you think that could be the issue? I will try to keep the reflector right next to the laser and see if that increases my reflection value.

In the end if you get a reliable reading and no false positives (too low threshold) or negatives (too low reflection) then you’re all set, but for the sake of experiment you can try spare reflective tag closer, in the dark and at different distances.

I installed the unit last night, works great!..last night only at least…

This morning at about 7:30am, I got multiples alert on my iPhone showing that the garage is ‘open’, ‘closed’, ‘open’, ‘closed’ continued for several times…and the garage HAS NOT BEEN TOUCHED open nor closed.

So I went to my garage, push open and close from the wall remote, push open and close from the app… and the alert finally stopped… but now the apps is showing ‘Open’ when the garage door is closed. Vice versa it would show ‘Closed’ when the garage is ‘Open’.

I am out of idea at this time… I’m not sure what is wrong?

Reflection rate has been 97% all the time.
Sensor Reads: 3
Sensors threshold: 25