This is great, far better than the garage door companies, for understanding how they work. It's not a good idea to bypass the sensors, but this can help you understand how to fix them. Note: on most garage door openers if you hold the wall switch, it will bypass the sensors and the door will go down.
Thanks for the analysis with the oscilloscope. That answers questions no one else on the internet had described as well. At least with over an hour of searching. This also shows how you cannot (nor should not) by pass these safety devices in any simple way. I am going to guess that in the controller board on the opener is a re-triggerable "timer" with a time constant longer than the 6 mS pulse. So long as a pulse arrives to re-trigger the timer before it times out the door is allowed to close. Good job MrEnergyFree.
Great video. 9 out of 10 garage door video's spent 5 minutes talking about aligning the sensors. WE KNOW HOW TO ALIGN SENSORS. From your video I was able to figure out WHY you can't just jump the common ground (2) with the sensor (3) post and take out the sensors all together, you need the timed pulse that the sensors provide.I was able to troubleshoot by taking the wire runs out of the equation and hooking the sensors up directly to the drive unit. Also nice to know the voltages, next time I'll just check for voltage at the sensors. In the end I had 1 shorted (+) wire in the attic that presented a curve ball at the unit when trying to diagnose. So the 3 hours I spent tonight will help me out next time. Thanks again, good to know HOW it works before you just try and follow someones steps blindly.
Thanks for this highly informative piece. I couldn't find any other explanative post. There may be a minor inaccuracy around the 10:15 mark. I think the transmitter is just emitting a IR beam. As long as the receiver sees the beam, a timer in the pulls the positive wire to ground briefly after ~650 ms and resets itself. No need for an oscillator anywhere. But, I don't know if I am correct. Your solution is also quite simple and brilliant. Thank you for your effort. I wish there were more people like you, instead of those that question the need for the solution.
I wanted to confirm that I have a bad receiver sensor. The wiring checks good. Now I can order a replacement with confidence now that I see how they work. Thanks for the video.
Excellent! We are using garage door openers to open/close the roofs of remote controlled astronomical observatories. The safety sensors were taped together so the roofs would always operate. However the little black boxes are not waterproof proof. Or dust-proof. Dust obscured the optical port of one of the devices and dew and/or ice formed on the other after heavy rain! This disrupted the signal and made it impossible to control the roof remotely. I took the little boards out of the black boxes and, with the help of an EE friend, deduced what you have shown. We too were initially puzzled how the control signal could be sent without a third wire. Then I found the tiny surface-mount comparator that is being used as an oscillator on the IR transmitter board. This was a couple of weeks ago. I just now discovered your video. Good work! We will now be working to make our observatories reliable. This failure was occurring in two observatories. Very puzzling when you are hundreds of miles from the garage door controller...
Thanks... I learned a lot from this video. I will go back to figure out why my sensor lights are not lighting up and check them by connecting them direct to the screws and see if the lights come on. Keep up the videos like this. I appreciate your efforts because the manufacturers do not post these type of online videos to help us!
I had the same sun problem. I bought a replacement sensor set (about $25 from Amazon) and connected the transmitter sensor to a 2 AA battery holder from Radio Shack. Whenever the sun is an issue, I place my hand-held transmitter sensor next to the wired receiver sensor and close the door. This keeps the opener's safety components in place but gives me a simple/safe override when I need it.
Excellent video! Your explanation helped me to diagnose why our garage door will not close. I could not find information on how much voltage was required to operate the photo sensors. Your video explains it very well. Thank you!!!
Thank you, Sir. You really filled in the gaps in my knowledge. I'm working on one currently that looks to be the exact same brand & model. I measured 6+ vdc where the plug goes into the sensor (they're really old). No LED's come on either side. So I'm thinking: if I DO get past the fact nothing is even powering up, how can I determine it SHOULD be telling the unit the light hits the eye? You have given me the answer. Showed this to my buddy - he enjoyed it too. Good job!
While not what the title says, I was able to check with my scope what issue I was having thanks to the specs given in this vid. VERY HELPFUL and a quick test. In my case, the internal board had gone bad and was not sending the correct pulse voltage. Rather than just throwing parts at it or trying to disable the system, which is dangerous and the safety system must work if you are selling the house, for example, ( so you'd have to fix it correctly anyways) I was able to save time and have mine work correctly once again because of this vid. THX!
Thanks for posting this video. It was very helpful for me to troubleshoot a problem with my garage door sensor (loose connection at the base unit!) that was causing intermittent failures (door not closing completely before backing up).
Great video...saved me the time and trouble of eventually going through the same procedure after several hours of wasted time trying to see if I could bypass sensors. The answer....NO. Taping the sensors together like other people have done is really the only way. At least there is one way as long as you have two good working sensors. If not you're SOL. I understand why that is now....thanks again for showing this.
I really appreciate this video... just started troubleshooting my system and after looking at the schematic I was wondering what kind of signal was being used to via the photo-eye. Good job
Wow Simple for you. Your explanation was just awesome. Never had a clue that the sensors transmitted and received. Okay do not really understand about the mil sec pulses and how they work but I can see they are needed to make the door work safely. Thanks for putting this you tube together.
This is the very best video available for connecting the safety sensors on the Chamberlain lift master. It took me several days of searching until I found this video. The chamberlain website an documentation is useless without photos.. They should take notice of this video and add videos to their online support pages.
cool..i took electronics courses in college just to understand this concept and test it via oscilloscope... tons of potential in this concept for cars without auto reverse windows for safety!
Great video, I learned from your video that I could hold the garage door button down to bypass the sensors. That way I knew it was a sensor that went bad. I have it all up an working now, you saved me a ton of money and really explained what the sensors were doing! Thanks Again!
Amigo le felicito, no le entindi nada de su idioma .. pero lo explicaste tan perfecto que lo entendi muy bien. con todas las pruevas que haces..... espero que lo traduscas .... GRACIAS DE UN TECNICO DE VENEZUELA ........ SALUDOS....
I did this when I installed my opener. I mounted both sensors to a board with six inches between them to test the functionality and left it that way for years. Without kids and pets, it's a low-risk situation since the pressure and limit sensors are still working.
Excellent video. I have been having trouble with my opener and this explains it. I'll hoo up my scope this weekend and see what I have. Thank you very much....good job.
The reason the opener works when you short out one and two is because that is normally that's where a wall button would go.. the wall button will open and or close the door at any time. With with a wall button you have line of sight on your garage door. Or you should and that is an override for The Infrareds. So when you short out 1+2 or bridge them basically what you're doing is you're pushing the button on the wall. Normally you push it and let go it's a quick short enough to signal the motor to move. However when bridging it or holding the button and not letting go you are overwriting the infrareds you're allowed to do that because once again because you have the line of sight. This is a built-in feature of every garage door opener..it's basically there in case you can't close your door and a guy like me can't come to your house within 10 minutes if you want me to be there it'll get your door closed for the evening and you can once again you have line of sight and its owner or user responsible at that point. This will not work with remote controls your remote controls cannot override your Infrareds only your button on the wall and once again why because you have line of sight or at least you should. I'm pretty sure the new UL 325 doesn't allow for it button anywhere besides inside the garage with a line of sight on there garage door opener and garage door. Newer garage doors you can close from your phone will emit a siren or an alarm for 10 seconds before closing the door there is absolutely no way to override your Infrareds believe me we've tried we've tried hundreds of times every which way we can there is no way to override it unless you want to start taking circuit boards apart and redoing them you pretty much can't do it. . And with small children and pets valuable cars. Why would you want too? Keep them clean. Don't put shit near them and don't let your dog piss on them. They will last 20 years or at the very least the life of the opener. There's always the exception to the rule but for the most part they don't go bad. Any garage door guy that comes your house and tells you you've got bad Infrareds is most likely lying to you. You've either got a cut wire or they are not lined up. How do I know this ? I've been doing Garage Doors Gates and Operating Devices as a licensed contractor for well over 30 years now that's how I know. You're all very welcome
All true. However, saying it's impossible to actually bypass them is not true. I can pretty much garuntee you that if I found out the right pulse timing for my opener, and then using an Arduino or really anything similar, some other bits and pieces to match voltage, and 30 mins of programming, I could use that to trick the opener. Removing the actually sensors completely. But why go through all the effort when you can just tape the two of em together in 2 mins and boom, you're done, same result, less work.
He DID show you how to bypass it...duh. Disconnect the green sensor, splice it into the wires feeding the yellow sensor, mount or tape the sensors to something so that they stay facing each other, and wallah...technically the sensors ARE bypassed.
Do you think that the garage door controller is actually looking for the voltage pulses or if it is just seeing a reduced average voltage (kind of like a switched power supply)?
This video is definitely only for educational purposes. I bought an opener with an optical sensor, but in 2 tests out of about 100, the door didn't stop closing when it was blocked. Then a few days later a child in a nearby city was crushed by an opener (brand unknown), so I take down my new opener and get another brand that I've never been able to make fail. The optical sensor is the only safety device that works really well. Don't defeat it.
This is good information. I was thinking that I could use a jumper to bypass the sensor to test whether the sensors are bad or something in the motor box. Now I see that I cannot. BTW the light does change states when the beam is blocked so it not likely an alignment issue. This doesn’t mean that the signal is getting to the motor box. Since I left my o-scope in my other pants, I’m pretty sure that I can use the frequency mode on the DMM. Question: is the pulsating signal generated at the sensor or in the motor box?
Thanks for the o-scope readings MrEnergyFree, I leant my o-scope to a friend in another town and it will probably be a couple weeks before I see him again and retrieve it. My garage doors sensor stopped working, and I was able to use this information to create a bypassing circuit. For others, the circuit diagram can be found seen at 206.255.233.35/garagedoorsafetyeyeshack.bmp, until my ISP changes my IP.
Thanks for showing the signals; from that I could tell my Rx was wierd since it still had some kind of pulsing even with a blocked beam. With an open beam, the waveform was never clean, looked like lots of RC filtering. **However** the video title is 'bypass garage door safety sensor", but you never did showed how to do this. I wanted to do until temporarily until the new parts came in..
Thanks for the video, it's great! I can hardly believe all the idiots making negative comments. I guess that's the world we live in though... people expect an instant answer and don't want to learn anything in the process of copying someone else's work.
Would be interesting to look at the signal on the garage door opener feed lines to the sensors with the scope to see if the pulse is present without the transmitter in the circuit. I'll bet it is. This would allow the garage door device to send the signal, then look for a return through the photo-eye path and the two would need to be in phase. That would keep an alternate square wave from replacing the transmitter signal. Simple but effective.
After looking at the waveform it seems pretty simple to override the sensors. Assuming the High of the pulse is 6 volts and the Low is zero all you would have to do is have a pulse generator that controls a switch to short out post 2 and 3. It would generate a 154 Hz (1/0.0065) frequency pulse with an 8% (0.5/6.5) duty cycle. When the pulse goes high the switch is turned on and shorts post 2 and 3. When the pulse goes low the switch is open giving the open circuit voltage of 6 volts. Get your self an arduino and a transistor and your in business.
Are those two wires merely supply power to the sensors or are they doing more than that? is the momentary off sequence initiated by the main controller unit based on signals it read from the sensors wirelessly or are the sensors causing a momentary short-circuit? Many questions.
I not sure but I will think that a set of sensor in parallel will help unless two set take too much power from the source. Would you like to tried and let us know.
Hey thanks man but i have some additional questions and i know there not the right solution to my issue but it is my issue and i choose to deal with it how i wish to deal with it to fir my own needs. With that said i see your very knowlegable and set up to test circuts and pulses etc and have a brilliant mechanical mindset so my question is what would be the workaround for bypassing the pulse and relay directly on that control board so its basically just the opener button and then the adjustments and transmitter have you tried to modify these boards to accomplish this and if so what all does it intail?
Oh not to mention no one operates my garage door anyways and couldn't even if they tried I have a integrated security system that prevents anyone from opening it that does not have the pin code from either side of it and transmitter is built into the app so I'm not worried about it possibly being dangerous to do because it's not all that dangerous since you can still bypass it by holding down the button any kid would and could find that out given I still had a original setup like most. 😅😅 So dangerous there's still a bypass right at the button on the wall... I guess it's more a question of how dangerous is the operator of it? I don't think I'd ever close my door on someone or something because I'm highly confident I don't want to hurt anyone and don't want to damage anything and if that occurred it would be my issue not the worlds just for all the finger pointers that may hate on my question and pursuit of further knowledge in the circut board.
The o-scope around 8:15 shows the inverse of the signal that is really being transmitted. The ground is hooked to 2 and the probe to 3. So every .5ms out of 6.5 ms the connection between 2 and 3 is closed, effectively grounding 3. When the beams are open there is no connection between 2 and 3, and the o-scope shows the full potential between them.
Hi Joel! Very usefull video! Few trouble-shooting video on this subject adress the voltage at the output of the sensors on the unit. My unit is a Lift-Master and I have a question for you: my voltage between 1 and 2 and between 1 and 3 is around 16 volts. But I have no voltage reading between 2 and 3. What would you think of those readings and why I do not see voltage between 2 and 3? (Your readings was 24v and 6v in your video). Thanks very much and have a good day!
Finally someone who ACTUALLY EXPLAINS the electric eyes.
Thank you! (12 years late)
This is great, far better than the garage door companies, for understanding how they work. It's not a good idea to bypass the sensors, but this can help you understand how to fix them.
Note: on most garage door openers if you hold the wall switch, it will bypass the sensors and the door will go down.
Thanks for the analysis with the oscilloscope. That answers questions no one else on the internet had described as well. At least with over an hour of searching.
This also shows how you cannot (nor should not) by pass these safety devices in any simple way.
I am going to guess that in the controller board on the opener is a re-triggerable "timer" with a time constant longer than the 6 mS pulse. So long as a pulse arrives to re-trigger the timer before it times out the door is allowed to close.
Good job MrEnergyFree.
Great video. 9 out of 10 garage door video's spent 5 minutes talking about aligning the sensors. WE KNOW HOW TO ALIGN SENSORS. From your video I was able to figure out WHY you can't just jump the common ground (2) with the sensor (3) post and take out the sensors all together, you need the timed pulse that the sensors provide.I was able to troubleshoot by taking the wire runs out of the equation and hooking the sensors up directly to the drive unit. Also nice to know the voltages, next time I'll just check for voltage at the sensors. In the end I had 1 shorted (+) wire in the attic that presented a curve ball at the unit when trying to diagnose. So the 3 hours I spent tonight will help me out next time. Thanks again, good to know HOW it works before you just try and follow someones steps blindly.
it took me about 6 months to find a smart video explain how to simple volt test and the connect terminals 1&2&3 with sensor ,
thanks you
What is the video markw@johnegreen.com
THANK YOU! Understanding HOW the system works has made it simpler for me to diagnose and repair my garage door opening issues!
Thanks for this highly informative piece. I couldn't find any other explanative post.
There may be a minor inaccuracy around the 10:15 mark. I think the transmitter is just emitting a IR beam. As long as the receiver sees the beam, a timer in the pulls the positive wire to ground briefly after ~650 ms and resets itself. No need for an oscillator anywhere. But, I don't know if I am correct.
Your solution is also quite simple and brilliant. Thank you for your effort. I wish there were more people like you, instead of those that question the need for the solution.
I wanted to confirm that I have a bad receiver sensor. The wiring checks good. Now I can order a replacement with confidence now that I see how they work. Thanks for the video.
Excellent! We are using garage door openers to open/close the roofs of remote controlled astronomical observatories. The safety sensors were taped together so the roofs would always operate. However the little black boxes are not waterproof proof. Or dust-proof. Dust obscured the optical port of one of the devices and dew and/or ice formed on the other after heavy rain! This disrupted the signal and made it impossible to control the roof remotely. I took the little boards out of the black boxes and, with the help of an EE friend, deduced what you have shown. We too were initially puzzled how the control signal could be sent without a third wire. Then I found the tiny surface-mount comparator that is being used as an oscillator on the IR transmitter board. This was a couple of weeks ago. I just now discovered your video. Good work! We will now be working to make our observatories reliable. This failure was occurring in two observatories. Very puzzling when you are hundreds of miles from the garage door controller...
Thanks... I learned a lot from this video. I will go back to figure out why my sensor lights are not lighting up and check them by connecting them direct to the screws and see if the lights come on. Keep up the videos like this. I appreciate your efforts because the manufacturers do not post these type of online videos to help us!
I had the same sun problem. I bought a replacement sensor set (about $25 from Amazon) and connected the transmitter sensor to a 2 AA battery holder from Radio Shack. Whenever the sun is an issue, I place my hand-held transmitter sensor next to the wired receiver sensor and close the door. This keeps the opener's safety components in place but gives me a simple/safe override when I need it.
Excellent video! Your explanation helped me to diagnose why our garage door will not close. I could not find information on how much voltage was required to operate the photo sensors. Your video explains it very well. Thank you!!!
Thank you, Sir. You really filled in the gaps in my knowledge. I'm working on one currently that looks to be the exact same brand & model. I measured 6+ vdc where the plug goes into the sensor (they're really old). No LED's come on either side. So I'm thinking: if I DO get past the fact nothing is even powering up, how can I determine it SHOULD be telling the unit the light hits the eye? You have given me the answer. Showed this to my buddy - he enjoyed it too. Good job!
nice technical discussion explaining why you can't just bypass the transmitter/receiver. Thanks!
Thank you. You saved me from getting my equipment out and figuring out the circuit. 555 will work great.
This electrical engineer gives you a big thumbs up.
While not what the title says, I was able to check with my scope what issue I was having thanks to the specs given in this vid. VERY HELPFUL and a quick test. In my case, the internal board had gone bad and was not sending the correct pulse voltage. Rather than just throwing parts at it or trying to disable the system, which is dangerous and the safety system must work if you are selling the house, for example, ( so you'd have to fix it correctly anyways) I was able to save time and have mine work correctly once again because of this vid. THX!
Thanks for posting this video. It was very helpful for me to troubleshoot a problem with my garage door sensor (loose connection at the base unit!) that was causing intermittent failures (door not closing completely before backing up).
Great video...saved me the time and trouble of eventually going through the same procedure after several hours of wasted time trying to see if I could bypass sensors. The answer....NO. Taping the sensors together like other people have done is really the only way. At least there is one way as long as you have two good working sensors. If not you're SOL. I understand why that is now....thanks again for showing this.
Very nice and well prepared video.
It is a very well explained how sensor works and why it protect when door is moving down. Good job.
Ah, you are the originator of this fix! Nice job.
I really appreciate this video... just started troubleshooting my system and after looking at the schematic I was wondering what kind of signal was being used to via the photo-eye.
Good job
Exact what I need to know finally someone explains exactly the right connection...thank you I so much
Wow Simple for you. Your explanation was just awesome. Never had a clue that the sensors transmitted and received. Okay do not really understand about the mil sec pulses and how they work but I can see they are needed to make the door work safely. Thanks for putting this you tube together.
Finally someone with technical acumen to explain my problematic garage door. Thanks. But why do they pulse it. Why isn't it just a photointerrupter?
so you cant just short the terminals out
And asked to be a pulse otherwise any source of light within the Frequency range could cause your door to reverse
This is the very best video available for connecting the safety sensors on the Chamberlain lift master. It took me several days of searching until I found this video. The chamberlain website an documentation is useless without photos.. They should take notice of this video and add videos to their online support pages.
cool..i took electronics courses in college just to understand this concept and test it via oscilloscope... tons of potential in this concept for cars without auto reverse windows for safety!
I've wanted to see how to bipass the sensors, but by looking at the oscilloscope explanation I've learned a hole lot...thanks anyway
I'm relieved I'm not the only one who finds those jumpers hard to deal with!
Thanks for the technical information especially with the oscilloscope output. Since I do not have a scope, this was very helpful!
I would like to say thanks for the video . it will help me determin if I have bad sensors or bad wiring . thanks a bunch !
Very good video thank you so much. Save me the effort of climbing up there and trying to figure it out myself.
Very useful info, I am using garage door sensors for a project and needed to see how to wire them and get a signal, will give it a try!
Thanks for the explanation. Great help in troubleshooting a problem with my opener.
Just did mine, thanks for sharing, some of your viewers are not paying attention
Thank you for this video and excellent explanation of how the sensors work. Now, I'll have to work on a circuit to bypass them.
+Lee Dabkey
Look in my channel for new video "Bypass Garage Door Sensor using 555 timer " for the electronic circuit.
This is a great video, good explanation, very concise.
Great video, I learned from your video that I could hold the garage door button down to bypass the sensors. That way I knew it was a sensor that went bad. I have it all up an working now, you saved me a ton of money and really explained what the sensors were doing! Thanks Again!
Amigo le felicito, no le entindi nada de su idioma .. pero lo explicaste tan perfecto que lo entendi muy bien. con todas las pruevas que haces..... espero que lo traduscas .... GRACIAS DE UN TECNICO DE VENEZUELA ........ SALUDOS....
Thankyou Sir......needed this explanation ...may god bless you.
Thanks to this video i fixed my garage door and saved me lots of headaches and time,i didn't know what to do with the sensors, thanks a lot bro : )
I did this when I installed my opener. I mounted both sensors to a board with six inches between them to test the functionality and left it that way for years. Without kids and pets, it's a low-risk situation since the pressure and limit sensors are still working.
Very cool video...now I know the principles behind how these camera's work. Good job!!
Nicely done video.....helps explain in a very straight forward manner.
Great demonstration! That is what I like to see!
Great video man thanks for taking time to show everything.....
Excellent video. I have been having trouble with my opener and this explains it. I'll hoo up my scope this weekend and see what I have. Thank you very much....good job.
Really helpful, excellent video MeEnergyFree! This enabled me to find that the cable to the transmitting sensor was broken. Thank you very much.
Thanks your video was very helpful. Now I know that bypassing the sensors would be difficult off of the board.
The reason the opener works when you short out one and two is because that is normally that's where a wall button would go.. the wall button will open and or close the door at any time. With with a wall button you have line of sight on your garage door. Or you should and that is an override for The Infrareds. So when you short out 1+2 or bridge them basically what you're doing is you're pushing the button on the wall. Normally you push it and let go it's a quick short enough to signal the motor to move. However when bridging it or holding the button and not letting go you are overwriting the infrareds you're allowed to do that because once again because you have the line of sight. This is a built-in feature of every garage door opener..it's basically there in case you can't close your door and a guy like me can't come to your house within 10 minutes if you want me to be there it'll get your door closed for the evening and you can once again you have line of sight and its owner or user responsible at that point.
This will not work with remote controls your remote controls cannot override your Infrareds only your button on the wall and once again why because you have line of sight or at least you should. I'm pretty sure the new UL 325 doesn't allow for it button anywhere besides inside the garage with a line of sight on there garage door opener and garage door. Newer garage doors you can close from your phone will emit a siren or an alarm for 10 seconds before closing the door there is absolutely no way to override your Infrareds believe me we've tried we've tried hundreds of times every which way we can there is no way to override it unless you want to start taking circuit boards apart and redoing them you pretty much can't do it. . And with small children and pets valuable cars. Why would you want too? Keep them clean. Don't put shit near them and don't let your dog piss on them. They will last 20 years or at the very least the life of the opener. There's always the exception to the rule but for the most part they don't go bad. Any garage door guy that comes your house and tells you you've got bad Infrareds is most likely lying to you. You've either got a cut wire or they are not lined up. How do I know this ? I've been doing Garage Doors Gates and Operating Devices as a licensed contractor for well over 30 years now that's how I know. You're all very welcome
All true. However, saying it's impossible to actually bypass them is not true. I can pretty much garuntee you that if I found out the right pulse timing for my opener, and then using an Arduino or really anything similar, some other bits and pieces to match voltage, and 30 mins of programming, I could use that to trick the opener. Removing the actually sensors completely. But why go through all the effort when you can just tape the two of em together in 2 mins and boom, you're done, same result, less work.
Outstanding video. Thanks!
Thank for the information you provided on how the eye sensors work, but nothing about "Bypass" garage door safety sensor.
He DID show you how to bypass it...duh. Disconnect the green sensor, splice it into the wires feeding the yellow sensor, mount or tape the sensors to something so that they stay facing each other, and wallah...technically the sensors ARE bypassed.
UsMaLeMan1 Actually, technically the sensors are not bypassed since they are still in the circuit. It is only the safety feature that is bypassed.
+FYIGuy01
Look in my channel for new video "Bypass Garage Door Sensor using 555 timer " for the electronic circuit.
bravo -- I was trying to get it to work without the light sensor .. no way possible
yes, there is a way. Look in my videos for 555 timer.
Very good demonstration, thank you
Do you think that the garage door controller is actually looking for the voltage pulses or if it is just seeing a reduced average voltage (kind of like a switched power supply)?
Thank you for this video! Wish I could give you the money I saved!! awesome job!
Excellent video, very well explained.
This video is definitely only for educational purposes. I bought an opener with an optical sensor, but in 2 tests out of about 100, the door didn't stop closing when it was blocked. Then a few days later a child in a nearby city was crushed by an opener (brand unknown), so I take down my new opener and get another brand that I've never been able to make fail. The optical sensor is the only safety device that works really well. Don't defeat it.
A good clear explanation - thanks
This is good information. I was thinking that I could use a jumper to bypass the sensor to test whether the sensors are bad or something in the motor box. Now I see that I cannot. BTW the light does change states when the beam is blocked so it not likely an alignment issue. This doesn’t mean that the signal is getting to the motor box.
Since I left my o-scope in my other pants, I’m pretty sure that I can use the frequency mode on the DMM.
Question: is the pulsating signal generated at the sensor or in the motor box?
Thanks for the o-scope readings MrEnergyFree, I leant my o-scope to a friend in another town and it will probably be a couple weeks before I see him again and retrieve it. My garage doors sensor stopped working, and I was able to use this information to create a bypassing circuit.
For others, the circuit diagram can be found seen at 206.255.233.35/garagedoorsafetyeyeshack.bmp, until my ISP changes my IP.
Thanks for showing the signals; from that I could tell my Rx was wierd since it still had some kind of pulsing even with a blocked beam. With an open beam, the waveform was never clean, looked like lots of RC filtering.
**However** the video title is 'bypass garage door safety sensor", but you never did showed how to do this. I wanted to do until temporarily until the new parts came in..
Cool. So I was able to bypass the sensors by holding the button down until the door closed all the way. Thanks.
Thanks! Excellent explanation and good info to a mystery...saved me some time and effort!
Thanks for the video, it's great!
I can hardly believe all the idiots making negative comments. I guess that's the world we live in though... people expect an instant answer and don't want to learn anything in the process of copying someone else's work.
+Jason Riley
I made a instant answer video on my channel look for "Bypass Garage Door Sensor using 555 timer "
Very nice. Thank you for taking the time to make this video. Very helpful!
Very interesting. Now know how those pesky things actually work. Thank you
This is Richard Gellis, and my comment" this vid provides all that's needed to be said, take heed, proceed.
Thanks alot this help me fix my garage 💪🏽
Great video. Thanks!
I've wanted to know how the safety sensor system worked with only 2 leads (Power and Com.) on both heads for a while now. Thank you so much.
Thanks for the video. Very helpful.
Would be interesting to look at the signal on the garage door opener feed lines to the sensors with the scope to see if the pulse is present without the transmitter in the circuit. I'll bet it is. This would allow the garage door device to send the signal, then look for a return through the photo-eye path and the two would need to be in phase. That would keep an alternate square wave from replacing the transmitter signal. Simple but effective.
Again, brilliant job, sir.
Very clear explanation, I save $300 for I did by my self
Excellent video!
Good video, and just what I needed: thanks for posting it.
Great video. I learned a lot after watching this video.
Video title: Bypass garage door safety sensor
Description: This video does not show how to bypass the garage door safety sensor.
Ahem....
+Simon Gabriel
Look in my channel for new video "Bypass Garage Door Sensor using 555 timer " for the electronic circuit.
MrEnergyFree a
Very useful episode
Esto explica mucho el problema que tenia tratando de bypasiarlo. Gracias hermano.
Stradi Varius entra al board electric y lo haces bypass
Thank you! That helped me understand a lot.
After looking at the waveform it seems pretty simple to override the sensors. Assuming the High of the pulse is 6 volts and the Low is zero all you would have to do is have a pulse generator that controls a switch to short out post 2 and 3. It would generate a 154 Hz (1/0.0065) frequency pulse with an 8% (0.5/6.5) duty cycle. When the pulse goes high the switch is turned on and shorts post 2 and 3. When the pulse goes low the switch is open giving the open circuit voltage of 6 volts. Get your self an arduino and a transistor and your in business.
+Anthony Shelton
Look in my channel for new video "Bypass Garage Door Sensor using 555 timer " for the electronic circuit.
Are those two wires merely supply power to the sensors or are they doing more than that?
is the momentary off sequence initiated by the main controller unit based on signals it read from the sensors wirelessly or are the sensors causing a momentary short-circuit? Many questions.
Great video , thanks for putting in time
very good video I learned allot..thank you very much..keep up the great videos
Thank you very very much. Just what I needed and what I suspected was happening.
Thanks!!! You saved my weekend!!!!!
Thanks worked out for me😀
Excellent demonstration! Thank You
Big help. Thank you.
I not sure but I will think that a set of sensor in parallel will help unless two set take too much power from the source. Would you like to tried and let us know.
Why the hell does this video come up when I search HOW TO bypass???
Because it tells you everything you need to know to bypass the sensors.
+Jason Riley
Look for "Bypass Garage Door Sensor using 555 timer" in my channel and you will know how.
ruclips.net/video/b4PNrtJChgU/видео.html
Great man! exactly what I wanted to know. Thanks for taking the time and sharing!
your video I helped me out a lot
gracias
Thank you! You deserve 👍
Hey thanks man but i have some additional questions and i know there not the right solution to my issue but it is my issue and i choose to deal with it how i wish to deal with it to fir my own needs. With that said i see your very knowlegable and set up to test circuts and pulses etc and have a brilliant mechanical mindset so my question is what would be the workaround for bypassing the pulse and relay directly on that control board so its basically just the opener button and then the adjustments and transmitter have you tried to modify these boards to accomplish this and if so what all does it intail?
Oh not to mention no one operates my garage door anyways and couldn't even if they tried I have a integrated security system that prevents anyone from opening it that does not have the pin code from either side of it and transmitter is built into the app so I'm not worried about it possibly being dangerous to do because it's not all that dangerous since you can still bypass it by holding down the button any kid would and could find that out given I still had a original setup like most. 😅😅 So dangerous there's still a bypass right at the button on the wall... I guess it's more a question of how dangerous is the operator of it? I don't think I'd ever close my door on someone or something because I'm highly confident I don't want to hurt anyone and don't want to damage anything and if that occurred it would be my issue not the worlds just for all the finger pointers that may hate on my question and pursuit of further knowledge in the circut board.
The o-scope around 8:15 shows the inverse of the signal that is really being transmitted. The ground is hooked to 2 and the probe to 3. So every .5ms out of 6.5 ms the connection between 2 and 3 is closed, effectively grounding 3. When the beams are open there is no connection between 2 and 3, and the o-scope shows the full potential between them.
Told me exactly what I needed to know.
+1
THANK YOU so much for explaining that.
Hi Joel! Very usefull video! Few trouble-shooting video on this subject adress the voltage at the output of the sensors on the unit. My unit is a Lift-Master and I have a question for you: my voltage between 1 and 2 and between 1 and 3 is around 16 volts. But I have no voltage reading between 2 and 3. What would you think of those readings and why I do not see voltage between 2 and 3? (Your readings was 24v and 6v in your video). Thanks very much and have a good day!