Willllll doooo 
. The wire runs up to my attic then along the beams where 2 walls are (roughly 22ft and 18ft ish), then down out of the attic lol. Lots of wire but makes it look super clean
Ok. I thought about this earlier and now I have to know if it would work. So I forgot I had an extra visor remote for my garage door. If I wired the xEM to one of the buttons wouldnât it make it I wireless system. My only problem would be decreasing the voltage from 12v at the xEM to the remote board which uses a 3v battery. Wasnât sure if I could just put in 2 resistors in series.
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no that wont work, the issue is is the xAC gives out +12v when a valid tag is scanned. look at this diagram below the switch is the button in the remote, as for your 3v yes voltage divider tapped off the 12v (red wire) and feed that into the remote instead of the battery (make sure to remove it).
I also donât understand the point of the 3rd resistor is in that voltage divider, it will work with 2 (10k and 3k3).
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Donât really understand the 3rd resistor either its a screenshot from the electrodroid app I have. I was a little confused by your response. It looks like the board would be connected to the signal wire and to ground, but in your response you said the resistors should be added between the red wire and the ground. The 12v power supply goes the the xEM and then sends the signal to the board right? So I would remove the battery and wire the signal wire with the resistors in line and then another wire from the board to ground to complete the circuit.
Is that right or am I way off base. LOL thanks for the help.
No⌠donât do this. Iâve explained this elsewhere, but basically you are going to burn shit out.
A button is a simple device. It shorts two contacts. Thatâs all. Itâs literally just a piece of metal that you physically press down that shorts two conductors together. Typically speaking, the circuit designed to detect user interface button presses (basically all low voltage digital devices) has itâs own ideas about the electrons it wants to push down one of those conductors, and detect coming back in on the other conductor once the button is pressed (shorting them together).
Think of it like a toy train set⌠a big circle⌠and youâre there, cross-legged on Christmas morning, playing with your toy train set⌠and you have a little drawbridge in part of the track so imaginary sailboats can make their way through⌠and your drawbridge is up⌠so your train waits⌠well that drawbridge is the button. Once the button is pressed, the drawbridge is lowered and your little train of electrons can mozey on over the drawbridge and continue on their way.
Now letâs say your dad comes in with a hotwheels toy car track and glues it to the drawbridge and says âhere come the cars motherfucker!â and instead of a tiny toy car making itâs way down the hotwheels track, he drives his 1967 Ford Mustang GT over you, your shitty little train track, the Christmas tree, and the dog. Thatâs what itâll be like if you try to connect the access controllerâs output wire directly to the button of your garage door remote.
So whatâs the answer? A relay. A relay is what? Itâs a device that shorts conductors together on command. Sounds kinda like a button right? Thatâs right, it is just like a button⌠only a button that you can control with another circuit! You connect a relayâs electromagnetic coil pins to the white output wire and GND of the access controller⌠when the output wire goes active, the relayâs coil will physically pull the contacts closed. Therefore, you solder the relayâs contact pins (the common pin and NO or ânormally openâ pin) to your garage door openerâs button conductors, and boom⌠you have an alternative, access controller controlled way to short the conductors of the button in your garage door remote⌠and you, the dog, your shittly little train track, and the Christmas tree all get to live (well, not the Chistmas tree, itâs already dead⌠just doesnât know it yet).
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I think this is one of my favourite posts on this entire forum. Educational and hilarious.
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donât forget to nominate it for BEST POST OF 2020!
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Thanks man its all so clear now.
I need to let Rudolf the red-nosed relay guide my wayâŚ
Would that work? Just wire it the same as if I was wiring it to the button on the wall?
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The 3rd resistor (RL) is an imaginary resistor representing the ESR of the load - usually calculated using the supply voltage and current draw. In the case of the remote, current used is tiny, therefore RL is so large as to be basically irrelevant and can be ignored.
Generally you want the current through the load to be an order of magnitude less than the current through R1+R2 (i.e. 10%) to keep the voltage stable under load. This just is a weird way to let you enter your expected current so it can change the voltage divider resistors to allow the right amount of current while keeping their ratio the same to maintain the voltage.
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Yeah i spotted that after some sleep, it was early am.
@darkdragon885 yes thats what I was trying to get at, wire it exactly the same as a wall button.
For your 12v to 3v tap it off pretty much anywhen that is 12v permanent.
It didnât seem like you to miss a trick like that! Thought Iâd post the reply for the sake of prosperity and accurate archiving!
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Got another question for you guys, since I have to buy the parts to do this anyway, would you suggest using an automotive relay or is there a cleaner way I can put this together?
Can you solder? There are a number of small relays that have pins to solder into circuit boards. Plus you can get circuit boards that are just rows of holes. This also makes mounting diodes, etc, much easier.
But⌠for the circuit board, Iâd try amazon. Better selection. For the relay, stay name brand.
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Thanks, I didnât even think of using a blank board. Thats a great idea.
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Continuing the discussion from xEM access controller for garage door question:
Ok here we go guys I feel like I am missing something obvious. I have a 12v power supply connected to my red and black wires of my xAC, the white signal wire has a diode in it and is connected to the board on the right, on the board I have my capacitor and diode connected to my 12v relay. The relay is a G5Q-14 and is 12v. It has 5 pins in the photo looking at the back of the board going clockwise om the data sheet the pins are 5, 1, 2, 3, 4. The coil is between 5 and 1, 2 and 3 are NO and I think 2 and 4 are the NC. So I have my signal wire attached to 5 and my ground to 1, I have the wires from 2 and 3 attached to the button on the controller. I get an intermittent relay click but it seems random. Iâm so confused. Here are some photos not sure how well everything can be seen. Stupid question the black wire that splits one split goes to the xAC and the other goes to my bread board right? What the hell am I missing here?
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First of all⌠Sweet!
NextâŚ
You have a system of sub systems. What you need to do is verify that each subsystem is working in the chain that makes up the greater system. Iâm gonna have you check it all the way through. I know itâs kinda obvious, but we need to rule out each part in order.
Step 1. Verify youâve got the actual power youâre supposed to have. Make sure it stays at a stable 12V while the access controller is active. All Good? Step 2.
Step 2. Need to verify that the access controller is getting a good clean repeatable read. It comes with a red LED on a wire for that purpose. Try reading it, and see if youâre getting the light to come on and stay on while reading. If it flickers or jumps around, youâre not getting a good read. Try enrolling one of the tags that came with it, you can usually just lay them on top of the antenna and itâll stay on. If that works, step 3.
Step 3. Verify youâve got good power and ground at the relay. Use an LED across the pins (WITH resistor!) or a multimeter. You should get good 12V power between pin 1 and 5. If thatâs good, then step 4.
Step 4. Check for continuity between pin 2 and pin 3. It should be closed when the relay is powered. If thatâs good, then the whole access controller circuit is working. It may be in how youâve adapted the openerâs circuit. Try removing the wires from pin 2 and 3, and then touch them together. It should work the opener.
That should be good for now, and those tests are gonna reveal 99% of the problems. If everything checks out, weâll try again for the weird 1% stuff.
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ok I think it might be a problem with the way i have the remote wired I get 12v at the source but only 9.8v across pins 1 and 5, the relay clicks though. I tried to connect it straight to the wall outlet like the other guy on the post did but either I did something wrong or reversed my wires cause now my wall switch is blinking and wont work. Thats a problem for another day. The wireless remotes still work.
Sorry if this seems idiotic, but I was looking at the pictures and the remote clearly has a place for a battery, but no battery. I can think of lots of reasons why that might be, but with nothing working, I gotta ask, Does the remote circuit board have a supply of appropriate voltage power?
That is a great question. Devilclarke suggested I split off and reduce the voltage from the 12v power supply. But it looks like I missed that step. It was a 3v battery. Gonna have to see if Iâve got some resistors on hand. Any other way I can do it?