I recently purchased the Infinity-Shield garage door sensor system. I want to use it to alert when a car on my hydraulic lift gets too close to the ceiling of my garage. I am powering the sensor from an old Genie garage door opener control board which works fine for this purpose. My problem is that the audible alarm that comes on the Infinity Shield system is too quiet. Does anybody know how I might get a signal from the garage door opener to drive a relay so I could add a light and or a louder alarm when an obstruction is sensed? The opener is fairly modern, I could buy an older one if that might help.

 

Can you access the Infinity Shield's audible alarm connections?

 

Link to product documentation? User manual, Installation manual, quick-state guide - Anything? And let's not forget the holy grail: Service Manual.

ak

 

Can you access the Infinity Shield's audible alarm connections?

Yes but with great difficulty. I did this but the signal to the alarm is complex. It varies between 1.5 and 3.5 on my multimeter. I will need an oscilliscope to get more definition and still would not know what to do with it. Then I decided to focus more on what is going on inside the openers control panel. There must be some output circuit change when an obstacle is sensed or so I was hoping. Old working openers are cheap to play around with also, like $20 each. The infinity shield units are $200 each.

 

There must be some output circuit change when an obstacle is sensed or so I was hoping.

Difficult to determine that without a schematic of the opener.

Were you measuring the Shield signal with the multimeter on AC or DC?

If the signal is some type of AC, it should be possible to convert it to DC, and then use that as a signal to turn on a louder alarm.

 

Difficult to determine that without a schematic of the opener.

Were you measuring the Shield signal with the multimeter on AC or DC?

If the signal is some type of AC, it should be possible to convert it to DC, and then use that as a signal to turn on a louder alarm.

I measured DC voltages. Thank you.

 

I measured DC voltages. Thank you.

That might be a measurement issue. In all of my old openers the reversible motor is 120 Vac, but all of the "logic" is 28 VAC relay coils and switches.

What are the acceptable limits (size, cost, holes in the ceiling, etc.) for other sensing options? Small ultrasonic distance sensors are under $5. One mounted to the ceiling above the center of the car could give you either a distance measurement to run through a comparator, or a simple near/far digital signal.

ak

 

Try measuring with the AC setting.

 

you already have the unit? how about some pictures of the controller unit (inside and out)? how about link to a datasheet or manual?

 

What are the acceptable limits (size, cost, holes in the ceiling, etc.) for other sensing options?

He already has the sensor.
He just wants to increase the intensity of the warning sound.

 

you already have the unit? how about some pictures of the controller unit (inside and out)? how about link to a datasheet or manual?

The oscilloscope screenshot sloping up is the signal to the beeper on the Infinity Shield sensor. There is also a blinking light on the infinity shield sensor and the signal to that is a pulsing 50mb to 100 mv at about 3hz. The website would not accept the video.

My latest thinking is to try to find another garage door opener that is new enough to have safety sensors but old enough to have manual door travel and force adjustments so I can set them without utilizing the controller in the opener that cannot be fooled when a door is not attached to it AND that triggers a 100v light bulb turning on when the safety beam is broken like when walking through a garage door opening when the door is already open. I am narrowing in a a Chamberlain model 2500 opener. Now just need to find one.

 

Look at the beeper signal with a slower sweep speed than 500µs/div (e.g. 1s/div) to see what it's actually doing over a longer period.

Buying a new garage opener board without really knowing if that will help, seems to be overkill for this problem.

 

Look at the beeper signal with a slower sweep speed than 500µs/div (e.g. 1s/div) to see what it's actually doing over a longer period.

Buying a new garage opener board without really knowing if that will help, seems to be overkill for this problem.

OK thanks, I'll check that tonight.

 

Their installation manual is useless, doesn't show much of anything at all. You'll never see a service manual as these are a replace when bad type thing.

However, essentially what they've done is take a photo eye light curtain, and added a custom onboard controller that communicates with the garage door opener.

Standard photo eyes are actually on a 2 wire bus that provides power and communication back to the opener. They pull one of the lines low in a specific pattern to tell the opener everything is OK.

The 2 dipswitches on these curtains are what tell the controller what protocol/pattern to use.

That said you can buy photo eye light curtains on Amazon that don't require trying to reverse engineer or find a garage door opener that does what you need.

Alternatively you can get beam detectors that are used on security alarm systems, they generally operate on 12/24v AC/DC and have a relay built-in. For example the Seco-Larm E960-D90Q is $83 on Amazon runs on 10-30 VAC/VDC and has a built in alarm relay rated for 120VAC 1A.

 

You could mount a CHEAP crystal or dynamic microphone over the beeper on the Infinity Shield and connect a small amplifier driving something like a car security alarm speaker for the warning. OR connect the mic in place of the glass break sensor input of a car alarm that drives the speaker.