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Tbone95 
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 Topic: Garage Door Safety Beam
Posted: 18 Jan 2025 at 9:54am |
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How do you semi-permanently defeat these? Is it simply a switch inside? Is just 2 wires each…Are the sensors typically interchangeable between brands? Got one Genie (not working right) and one Stanley working that I could use for troubleshooting. Need to be frugal for now!😎
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sparky
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Posted: 18 Jan 2025 at 10:53am |
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Mount them together nose to nose.
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It's the color tractor my grandpa had!
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Tbone95
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Posted: 18 Jan 2025 at 11:31am |
Yeah, in the process of doing that I ended up finding the broken wire!  Thanks
Edited by Tbone95 - 18 Jan 2025 at 11:35am
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SteveM C/IL
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Posted: 20 Jan 2025 at 11:58am |
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Mine are up above a couple inches apart. Small children and pets beware....
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Tbone95
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Posted: 20 Jan 2025 at 12:45pm |
 SteveM C/IL wrote:
Mine are up above a couple inches apart. Small children and pets beware.... |
The question really comes down to, if you had a bad one, can you fool the unit into thinking everything is fine.
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Harvey/pa
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Posted: 20 Jan 2025 at 1:15pm |
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mounted mine above the door on the header pointed at each other, has worked for 30 years...Harvey
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steve(ill)
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Posted: 20 Jan 2025 at 4:05pm |
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Tbone, i dont thing you can " wire around it".... everyone just tapes them looking at each other...... If one goes BAD, i think you are screwed..
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Like them all, but love the "B"s.
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Gary
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Posted: 20 Jan 2025 at 9:58pm |
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I found this on the internet, SO IT MUST BE TRUE !
G
Use Reflective Materials
Reflective materials can be employed to bounce the infrared beam back to the sensors, creating the illusion of an uninterrupted path. For garage door sensor bypass. place reflective tape or similar materials on surfaces near the sensors to achieve this effect.
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steve(ill)
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Posted: 20 Jan 2025 at 10:03pm |
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that does NOT eliminate the sensor... that was his question.. reflexting the beam is useless... WHY ?
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Like them all, but love the "B"s.
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Tbone95
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Posted: 21 Jan 2025 at 8:28am |
steve(ill) wrote:
Tbone, i dont thing you can " wire around it".... everyone just tapes them looking at each other...... If one goes BAD, i think you are screwed.. |
Thanks Steve, I figured as much. As I mentioned, I found a broken wire and everything is working now, but while my thinking was getting ahead of my doing I was wondering if they could just be eliminated.
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Les Kerf
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Posted: 21 Jan 2025 at 5:27pm |
Tbone95 wrote:
steve(ill) wrote:
Tbone, i dont thing you can " wire around it".... everyone just tapes them looking at each other...... If one goes BAD, i think you are screwed.. |
Thanks Steve, I figured as much. As I mentioned, I found a broken wire and everything is working now, but while my thinking was getting ahead of my doing I was wondering if they could just be eliminated. |
I would have to study a schematic but there has to be a way to wire around it. It is simply sending a go/no go voltage.
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jaybmiller
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Posted: 21 Jan 2025 at 5:35pm |
um, it might not be a steady beam..... I've seen them where the beam is actually pulsed ( high frequency ) so someone with a flashlight can't 'fake' the beam to open the garage door.
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steve(ill)
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Posted: 21 Jan 2025 at 5:45pm |
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its not an ON- OFF switch... If the door is OPENING and you stand in front of the beam, nothing happens... If the door is CLOSED and you stand in front of the beam, nothing happens.. If the door is MOVING DOWN and you stand in front of the beam, the door reverses direction.... There is LOGIC involved... not just OPEN- CLOSE ( on - off).
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Like them all, but love the "B"s.
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Les Kerf
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Posted: 21 Jan 2025 at 7:31pm |
jaybmiller wrote:
um, it might not be a steady beam..... I've seen them where the beam is actually pulsed ( high frequency ) so someone with a flashlight can't 'fake' the beam to open the garage door.
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Yes, I worked with photo eyes for years in the sawmill business, there are many types of photo eyes and not all of them use visible light, various frequencies, etc. The 'logic' is dealt with at the controller, the photo eye just says 'blocked/not blocked'.
Lacking the schematic and the ladder diagram it is difficult to know just where to tap into the system to defeat it. Maybe not a good idea anyway  |
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DaveKamp
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Posted: 23 Jan 2025 at 3:19pm |
It's a pulse transmit/receive signal train. If the transmitter doesn't talk to the operator in the proper way, you won't get a 'clear to operate' signal.
It's easier to open up the operator, yank the controller, and put in a simpler controller.
The operator runs on three signals... first is the 'command to run', the second is the 'direction to run' switch (either up or down), the last is 'excess load', which is a spring operated switch.
The Command To Run is a simple momentary. The Direction To Run is a two position toggle switch tripped by mechanical piece on the operator's mechanism (chain, gear, etc)... it's either in the UP, or DOWN position. It serves two functions... first, is to allow operating in one direction, the other is to STOP it when running to the limit of travel. If the machine is running in the UP direction, and the direction switch is tripped to the DOWN position, the operator stops.
It's not a complicated machine, they just added complicated hardware to prevent it from being modified.
When you press the button, the command-to-run signal energizes. The 'direction' setting engages either one wire (to go one direction) or the other wire (to go the other direction) for operating the motor. In old machines, this is nothing more than a 24v relay with two sets of contacts... one of which is tied to it's own coil to serve as a 'holding' contact. Press the button, the relay stays closed until power to the coil is cut off. The other sends power to the direction relay... whose two outputs (up and down) are connected to the motor's up direction winding, and down direction winding.
The motor starts in the direction identified... and it continues to run until the operator's limit switch contacts the 'direction' switch... which flips the DIRECTION switch... causing the motor to stop... as the motor direction switch has a pair of contacts in it that the HOLDING contact is looped through.
The last circuit element is the 'excess load' switch... which is nothing more than a microswitch depressed by a slider that the door operator works against (like, a chain tensioner, or the motor bracket) such that when an excessive load (in either direction) occurs, the tensioner or bracket shifts, causing the switch contacts to open. They're in series with the COMMAND TO RUN relay's holding coil. Put it in an 'excess load' state, and the relay just shuts off.
ANY door operator can be gutted of it's 'excess technology', and fitted up to operate in a realistic way.
Defeating the photobeam is more complicated, because the door operator's 'excess technology' is there to make it so you cannot easily 'defeat' it with anything other than a toilet paper tube and some duct tape.
The whole 'door beam' thing came as a result of 'supposition' that a child or pet could get injured or killed by a closing door. In reality, this never actually happened, because part of setting up the door, is adjusting the opening and closing forces... that 'excess force' switch has to be dialed up enough to lift the door (the counterweights and springs need to be set up right to make it work, right?), so the actual opening and closing forces are very low. In reality, a person can place their foot under the door, and it senses and reverses automatically.
In reality, the danger part of overhead door operators, isn't the operator, it's the door. Specifically, the weight fo the door, and the countersprings used to counteract the door's weight. Injuries from overhead doors come in three flavors:
1) Countersprings exploding on fatigue failure... most of the time this happens when nobody is around
2) People injured while adjusting overhead door countersprings, frequently springs that fail WHILE they're adjusting them...
3) Doors with failed countersprings FALLING on people.
Notice that NONE of these problems can be solved by the presence of a 'safety beam'.
Most of the problems with the Safety Beam come from the door NOT closing... including freezing the home, home invasion, and theft. The door doesn't close because the beam prevents it from allowing the door to close.
There's four categories of beam failure- Obstruction (dust, dirt, leaves and cobwebs, frost, snow, and ice)
Electrical failure (broken wiring) Beam system failure (transmitter or receiver going bad) Jamming (headlights, streetlights, or sunlight glare overpowering the beam).
Notice that last one? If I wanted to break into someone's home, I'd get a high-powered flashlight or laser pointer, set it up in a good position to glare that beam receiver, and when they went to close the overhead door, I'd wait 'till the door was almost all the way down, then I'd hit the flashlight (glare the beam) to reverse the door AFTER they'd walked into their house. Now the door is open, the bad guys can walk right in.
The beam is more of a danger than a protector.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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jaybmiller
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Posted: 23 Jan 2025 at 3:30pm |
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Nice writeup Dave but you can't shine a light at my GD to get in..... well not unless it's IR and running at 2048 Hz. A solid beam of light (car headlight, flashlight,etc) has ZERO effect. Have an 8 pin PIC controlling 'access'.
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DaveKamp
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Posted: 24 Jan 2025 at 6:51am |
jaybmiller wrote:
Nice writeup Dave but you can't shine a light at my GD to get in..... well not unless it's IR and running at 2048 Hz. A solid beam of light (car headlight, flashlight,etc) has ZERO effect. Have an 8 pin PIC controlling 'access'.
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Wise move, Jay... I've dealt with this problem on the systems at my folks' house. On theirs, glare off the pavement jammed the sensors, causing the door to not close. Too much technology for a 'safety feature' that has no actual standing.
That being said, it isn't a significant challenge for a hacker-kid to reverse-engineer an operator beam using an Arduino and a few off-the-shelf parts to do just that. What used to take significant talent, now just takes a few minutes shopping online and download a few pieces of code. Times have changed a whole lot since cramming assembler into the 16F84.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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jaybmiller
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Posted: 24 Jan 2025 at 7:07am |
I've used toilet paper rolls in the past to eliminate the 'it's now fall,sun poke head aroud house, floods the sensor' problem. Drove me nuts as it was a 'random' event. As for hackers, it really 'upsets' me that after 40-50 emails, NOBODY replies about my $5o anti-theft addition to any and ll vehicles being stolen. Truly 'hacker proof', no matter if they have the keyfob or not.
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Les Kerf
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Posted: 24 Jan 2025 at 8:05am |
As usual, Dave does his superb explanation of how things work. Thank you 
DaveKamp wrote:
It's a pulse transmit/receive signal train. If the transmitter doesn't talk to the operator in the proper way, you won't get a 'clear to operate' signal... |
Yup. Ultimately a Go/No Go after all of the pulses, frequencies, etc.
When I was in the Marines a half-century ago I was an avionics technician (COMMNAV). The IFF systems we worked on used a complex combination of frequencies/pulses to code the signals, ultimately to (I)dentify aircraft as (F)riend or (F)oe.
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Gateman
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Posted: 28 Mar 2025 at 4:14pm |
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Unfortunately, you cannot eliminate them the way it’s designed you can’t fake it. It’s an intermittent pulse signal.
Only option is mount them on the back of the motor one on each bracket coming down from the ceiling.
You can bypass them to close the door by holding the wall button down until it gets all the way closed, release the button just as it hits the ground and it’ll stay closed.
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BuckSkin
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Posted: 02 Apr 2025 at 7:21am |
DaveKamp wrote:
The beam is more of a danger than a protector.
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Well said; I totally agree.
DaveKamp wrote:
Injuries from overhead doors come in three flavors:
1) Countersprings exploding on fatigue failure... most of the time this happens when nobody is around
2) People injured while adjusting overhead door countersprings, frequently springs that fail WHILE they're adjusting them...
3) Doors with failed countersprings FALLING on people. |
When it comes to over-head doors, I have seen and experienced it all.
My father's huge tire shop had nine over-head doors, all of them big and two of them huge; the two largest were 20-foot wide and covered an opening 16-foot tall.
I have seen those big ones have a spring break and come slamming down.
I have seen springs break when standing on a ladder, wrenches and adjusting rods in hand. --- If you ever think a spring needs adjusting, you had best just replace it as it is probably on the verge of breaking.
And, I could not count the times when we would go to open a door and discover that the spring had broken sometime in the night when no one was around to get killed.
None of these doors were automatic; all were manual.
Edited by BuckSkin - 02 Apr 2025 at 7:23am
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Pat the Plumber CIL
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Posted: Yesterday at 8:03am |
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35 years ago I worked with an idiot who would bring a garage door opener with him to work. As we drove from job to job he would point and click until eventually a garage door would open. I would make him make sure they closed if I was with him. If I wasn't with him ,,,,.
Later in life I built a house and installed the cheapest garage door opener I could find . Would come home to find the garage door open at least one day a week. After I purchased door opener the tech changed to the constantly random changing signal in the openers. I unplugged it and haven't used it since. Small 8 foot door that I raise by hand . My 21 HD 2500 Chevy won't fit without pushing the door all the way up and blocking with a piece of 2x4 so the opener wouldn't work anyway.
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You only need to know 3 things to be a plumber;Crap rolls down hill,Hot is on the left and Don't bite your fingernails
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Gateman
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Posted: Yesterday at 8:23am |
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Todays operators are not like that lol
It’s practically impossible to trick the operator into opening nowadays. Liftmaster is one of the best ones on the market as of now, been installing them since the early 1980s
Someone years ago made a signal scrolling box
that could crack a code in 5 minutes or less to break in, that’s what started the code rolling engineering and it works great.
Liftmaster got ahold of one for testing and after several hours of running it never got the door to open.
It has a Billion code rolling system that changes every time you use the remote and is constantly changing.
Feel assured you’ll be fine if you get a new operator installed these days.
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BuckSkin
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Posted: Yesterday at 8:45am |
Pat the Plumber CIL wrote:
35 years ago I worked with an idiot |
I've had to work with so many idiots that I can't begin to remember all the stories.....
Your story brings to mind an event from when I was about 10-yrs-old.
My father had added an annex to our house that included a garage complete with automatic opener.
A transistor-radio-sized remote-control unit clipped onto and above the sun-visor of my mother's car.
For whatever reason, she had parked and abandoned me alone in that big blue Bonneville in the parking lot behind the Chevrolet garage in the neighboring town; I spent countless hours sitting abandoned in cars in various places during my childhood, often for hours in all sorts of weather --- do that today and she would end up on the 4-o'clock news in hand-locks and I would end up in foster care --- and would have probably been a lot better off for it.
Anyway, I got bored and was looking for something to play with and decided to press that big wide button on the garage door remote.
I did and one of those huge overhead doors on the back side of the Chevrolet garage started opening.
It is amazing how far away the Bonneville was parked from that door, like several hundred feet.
I figured that had something to do with me, so I pressed the button again and the door stopped midway.
That door was huge and made a lot of noise; and, by then, three or four garage employees had gathered outside, some looking up at the door mechanism and others looking around for some idiot with a remote.
I guess with the sun glaring on the windshield and me being so small, they didn't see me.
I figured I had better repair the damage I had done; so, I pressed the button again; and, instead of closing, the big door continued up; that really got those guys puzzled and brought out a couple more.
Discretion being the better part of valor, I decided I had best not press the button nor my luck anymore.
Which brings to mind another more recent story...
Friends had wasted their money and bought themselves a pathetic little shiny red new car and invited us out to eat with them to sort of break in the new car --- I never before saw such a shiny red car.
After eating, we ended up at the Super Walmart.
Heading back to the car, within about sixty feet, our chauffeur fished that big plastic pocket-filling gizmo out of his jeans and pressed a button --- KER-LUNNNNKKKK --- the trunk lid flew up on a car right beside us at the same instant that the lights winked and the doors unlocked on the shiny red car.
Besides us, there was not another living soul around that car; their trunk lid must have been on the same frequency as the door locks of the little red car.
Being a good Samaritan never turning out well, we stepped up our pace and left the scene before anyone connected that trunk lid being up with us.
I bet the car owners were quite perplexed when they came walking down that long aisle of cars and saw their trunk lid standing open.
Edited by BuckSkin - Yesterday at 9:15am
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Gateman
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Posted: Yesterday at 9:03am |
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😂 that’s funny, wonder if that caused an argument over who left the car open 😂
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BuckSkin
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Posted: Yesterday at 9:21am |
Gateman wrote:
It has a Billion code rolling system that changes every time you use the remote and is constantly changing.. |
Just curious as I know very little of such things....
Anything wireless works on a frequency, right ?
With all this random frequency changing, would it not be possible that at the very minute something that just happened to be on that frequency was activated that it could also operate the garage door ?
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DaveKamp
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Posted: Yesterday at 11:18am |
Yes, Buck- it's possible. Not as PROBABLE as it once was, but still possible.
The earliest garage door remote controls were around 46mhz, and merely generated an RF signal... when the receiver detected it, it would pulse a relay. If someone happened to operating a radio transmitter that was on some harmonic multiple (say 23mhz, or 15.3mhz), the receiver would hear the overtone 'image', and think it was hearing a valid signal. If a radio transmitter was generating lots of out-of-band noise (i.e. idiot-built CB amp) the airwaves would be loaded with noise all over, again, triggering the reciever.
Technology improved in stages since then.
Most remote controls, including garage door operators, are located at 432-433 megahertz, and use a variety of subcarrier codes. There's significantly more sophistication involved, so it's more difficult to defeat, but certainly not impossible.
If you pick up an inexpensive Software Defined Radio (Like an RTL-SDR), plug it into your laptop computer, and point a simple antenna at a transmitter, with your PC set to record the audio, you'll have found the frequency, and captured that transmitter's signal. Now you know what frequency the unit is on. The code it sent, however, changes each time the button is pressed. If you record it several times, you'll find the pattern.
After that, you'll just need to generate an appropriate frequency RF transmission, and blast through codes until you find the 'next' one of the sequence.
Difficult? Not if you're a radio guy and dedicated hacker with nothing else to do.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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jaybmiller
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Posted: Yesterday at 12:17pm |
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It is highly unlikely you can get the 'code' for rolling code if it's a Microchip product even when you know 'how-it-works'.
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Kubota BX23S lil' TOOT( The Other Orange Tractor)
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steve(ill)
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Posted: Yesterday at 12:29pm |
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Heck... Wife has a 2019 Ford Flex and i replaced the garage door opener ins 2021... and THEY CANT TALK TO EACH OTHER !!!.... Gots to use the "factory fob" that came with the opener !!!
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Like them all, but love the "B"s.
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FloydKS
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Posted: 19 hours 13 minutes ago at 6:28pm |
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I have a Ford Flex and have not tried to use the 'in car' opener cause the opener that came with the door works so why complicate things... that is my simple mind working. peace
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Holding a grudge is like taking poison and expecting the other person to die
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