xEM access controller V2

Usually this is where the confusions sets in, so hard to make sure we’re talking about the same thing. To keep it simple, let’s only talk about the xAC access controller v2.

In order to have it output a +12v like the v1 model did:
Ground is ground.
Relay common and xAC positive input are both connected to the +12v source.
Relay N.O. is connected to whatever load you wish.
No diode is necessary on the N.O. output. The v1 needed it, the v2 does not.

If your questions are about your circuit instead, then I’d really need to set down and understand it myself first.

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Just a quick note to anyone playing with the V2 - pay attention to the jumper S3… if its connecting i think pins 1+2 then the common (white wire) of relay is connected to the red wire (12V) through a 600 ohm(?) resistor and can supply 20mA. If its connecting 2+3 its a dead short to the back wire (ground).

If you’re interfacing with other systems and using it to ‘press’ buttons, you should remove this jumper to avoid having a common ground/sending power into things that don’t want it.

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I think im following you. Best practice would be to add a diode of the controller output Common prior to adding the 12v source so it doesnt backfeed. And then also adding a relay to the circuit prior to the garage button. Is there worry about the 12v feeding into the NO NC or the Exit wire and burning up the controller?
I get the board this weekend and have some meter tinkering to do I guess. If no worry about the 12v feeding then I can get away with only 2 relays. :crossed_fingers:

My concern is voltage feeding into the exit wire from the top bypass button and both the door choice button feedbacks into the NC feeds(these 2 would be on 99% of the time)

Long story short, I can’t really read the schematic in detail, which makes it hard to follow.
Maybe this helps?

This would be O.K., but unnecessary. The v2 doesn’t suffer from feedback issues the way the v1 did.

Nope. But do pay attention to what compgeek was talking about above.

I’m not sure where this reference comes from so I can’t share the source of the data with you, but you might want to find, and throw away, the jumper S3

If that seems confusing, then think of it as having an internal way of putting either power, or ground to the common on the internal relay, without needing to actually use the common wire. Could be useful for some things, could create an internal short if set to ground and power was run to the common wire. Be safe and ditch it.

I really need to get one of these here, and get my camera setup going.

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I’ve got you! I sourced my v2s from a different supplier before Amal added it to the store. I’m not sure what instructions the DT ones ship with, but I got this in broken English and investigated what it meant with a multimeter.

I found it can simplify wiring slightly if it’s being used in an application with a common power supply (diy locks) but otherwise it’s more trouble than it’s worth.

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Thank you both. Super excited. I think just playing with the meter once I get it should simplify most of my worries too. I know my use case is probably a push of limits but a fun adventure for me :slight_smile:

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@amal I got the replacement v2 and wired up a basic circuit to give it power, set the keys, and test the exit button function. Keys work perfectly. Sadly the blue exit wire to common doesnt actually function. Anyone running into this? I followed the video and ran blue to white(common). No action or indication. Everything else works perfectly and am excited to get to the next step but will have to buy a replacement to see if just super bad luck with boards or something. I even tried a wire short at the pin points on the back of the board to verify it wasnt the wire connector.
Figure I ask before ordering 1. Dont expect you to just keep replacing them.

I think Amal was mistaken. Blue to black should work.

The reason it worked for @amal in the video is I think S3 was still set to short white to black - if you’ve removed that jumper to have the full relay available to you then that’ll no longer work.

I have s3 set to jumper 2/3 for 12v common. Which do you suggest for the bypass with that setting. Sorry its like 6-7 hours past my bed time :wink:

Update. With 2/3 its blue to black. Arg that solves some things and for my build destroys others. Ok back to the drawing board post sleep

12v to common is fine as long as you know it’s only 20mA output. If you are doing an elaborate circuit, I suggest removing the jumper and throwing it as far away from your workbench as possible! The safest option if in doubt is to just connect the red to the white yourself using whatever resistor you deem appropriate to limit the current.

Done for now
Still need to figure out the chamberlain secure wall button opener because I cant bypass 2 things.

  1. Simple switch override at the opener wont work as a short
  2. open 2 doors at the same time with multiple openers (frequencies are offsetting each other and neither opener responds)
    Once I figure Either of them out I will be able to do both doors at the same time.

Went with jumper j3(?) as a ground aka jump 1/2
I added a power switch, bypass button, and door selectors (cant have both live at same time due to number 2 above)
Each selector is hardwired to a relay that controls a 3 button wireless garage door opener (could have just used one opener since it wont open both at the same time anyways. Not sure why all photos rotated 90*.


Button

Video in action

https://streamable.com/6r4ley

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@amal ,
Weird security question on the v2
Are the add / remove tags unique to each xAC?
Or could anyone use their add tag to program themselves to an existing setup

That would be no bueno

Pretty sure you put it in master learn mode and teach it your own master tag.

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Devil is correct, programming tags are unique and you program them yourself on your device. Just make sure you protect your PCB to prevent someone changing the masters and gaining persistent access.

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Pcb will be behind a safe door, only thing sticking thru will be the antenna loop

Just got to thinking if the tags weren’t unique that’s a problem

But I forget that the xAC is unlikely writing tags, so it’s just recording whatever random uid you present