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[on:]

Needing to know when my vehicle is just clear of the double garage door, garage door safety sensors would easily resolve issues with sunlight, mounting and eye protection. However, despite an extended search, I've found no projects using garage door safety sensors and the manufacturers seem completely offended that I want to repurpose their sensors. I have it working with a laser, but alignment is an issue and I am concerned about safety and durability.

I'd appreciate any experiences, pointers or links to using garage door sensors with an Arduino.

[Reply #1 on:]

you could use an ultrasound distance sensor instead, like the - SHARP 2Y0A02 F 9Y - which has a working range of 20-150 cm (~8 .. 60 inch)

sorry no experience with garage door sensors, do you have a link to the datasheet?

[Reply #2 on:]

you could use an ultrasound distance sensor instead, like the - SHARP 2Y0A02 F 9Y - which has a working range of 20-150 cm (~8 .. 60 inch)

I've seen and considered the ultrasonic & infrared distance sensors, tennis balls and tire stops. There are several vehicles that might be parked in either bay of the garage requiring vehicle identification and varied thresholds. The total plan is several sensors at varied heights to accommodate different vehicles.

Since nearly every garage door opener in the US (and I assume throughout the world) has a safety sensor, I concluded someone must know how they work.

[Reply #3 on:]

(and I assume throughout the world) has a safety sensor

No defintely not

Do you have any information about the sensor?

[Reply #4 on:]

I ordered these - http://www.amazon.com/gp/product/B005134PO8/ref=oh_details_o01_s00_i01 - then called Chamberlain about connecting them; the tech was very nice until I told him I wasn't connecting them to a garage door opener. One of the reviews talked about voltages, but when I connected them to the specified voltages, the LED on the sender did not illuminate. Genie makes a similar unit.

[Reply #5 on:]

Some discussion that might be relevant here: http://arduino.cc/forum/index.php/topic,100804.0.html

[Reply #6 on:]

Since nearly every garage door opener in the US (and I assume throughout the world) has a safety sensor, I concluded someone must know how they work.

You got links to those?

[Reply #7 on:]

I believe there are federal regulations requiring manufacturers of these to make them resistant to defeat or bypass; and my guess is that the companies making them also like to make lots of money selling replacements (that's what happened to me); so naturally they don't want to give you datasheets, etc.

[Reply #8 on:]

Some discussion that might be relevant here: http://arduino.cc/forum/index.php/topic,100804.0.html

Thanks wildbill - not sure why my searches didn't find that one, but there is good info there.

[Reply #9 on:]

I think many of those sensors are Infrared beam modulated at 38KHz. You could build you own with IR LEDs, a 555 timer to drive them, and typical 38KHz receivers like these:
http://goo.gl/2uwYM

And there are some good off-the shelf pairs of IR TRansmitter (Runs from 5V) and Receiver, (runs from 5V and has digital output), like these:
http://goo.gl/5Kbyp

DISCLAIMER: Mentioned stuff from my own shop... which is what I know about and found somewhere and put there   

[Reply #10 on:]

I think many of those sensors are Infrared beam modulated at 38KHz. You could build you own with IR LEDs, a 555 timer to drive them, and typical 38KHz receivers like these:
http://goo.gl/2uwYM

Do those allow a continuous 38Khz signal? Most IR receivers require some period of off time in the signal (and a 555 timer alone would be insufficient).

The only IR receivers I'm aware of that allow a continuous signal are these "Presence Sensor" sold by Vishay (TSSP57038, TSSP6038, TSSP4038, and TSSP58038).

[Reply #11 on:]

Do those allow a continuous 38Khz signal? Most IR receivers require some period of off time in the signal

Hmmm. I realize all the applications I've played with did pulse the 38KHz in some kind of bursts.. The burst control could be done with another 555 of course..

Most IR receiver ICs are designed to reduce their gain when they detect continuous 38kHz from a compact fluorescent light bulb. Their gain is at max when the IR pulses are in bursts of data.

(From a couple of web sources..)

Has anyone seen a working circuit with 2 555's (or a 556 dual timer chip) that puts out bursts of 38 KHz??   I know I can design one, but this is a wheel that I am sure has been invented already...  Didn't find one in quick search...

[Reply #12 on:]

garage door sensors are designed so you can't just put a jumper across them to defeat them, here is a complete analysis of them:


However photo transmitter receivers by themselves are dirt cheap.  You could conceptually build two lines of them at low resolution and  say an inch apart, by the door, that scan the incoming vehicle for the direction it is moving and its height so you know which vehicle it is and when it is clear of the door.

[Reply #13 on:]

I realize I'm late to the party here, but I was planning on something similar for my garage.  I'm going to program the Arduino to automatically close the garage door if it detects that it's been open for more than 5 minutes.  But before it closes the garage door, it will use ultrasonic distance sensors on the ceiling to make sure there isn't something in the way.  Seeing as I'll have different cars in the garage too, I figured I'd just set it such that it makes sure that the measured distance meets some minimum distance (approximately 7 feet or something just shy of the distance to the floor).  That way, it doesn't matter what car or object is in the way, because whatever it is will make that distance less than the threshold.  The larger measured area might mean you'll have to pull in a little farther than the garage door sensor would require, but it might be a simpler solution.

That's the idea, at least.  We'll see how well it pans out when my sensors get here from China.  :-)