Questions on setting up a magnetic lock entry for a door

First of all I basically have no clue about RFID systems, but have been frantically trying to learn.
I’m making a school bus into an RV.

I want to make a “shaved” door, with no handle outside.
I want to have an RFID entry into the bus, with the reader inside next to the
skin of the bus. So you would swipe your rfid object from the outside of the
bus, through the skin of the bus, and have the door pop open.

I’m looking at the xEM Access Controller V2, and have a couple of questions.

  1. It sounds like it’s an all in 1 item, and I wouldn’t need a card reader/writer like the proxmark 3 with it?

  2. I can’t imagine the small antenna/reader on it would receiver through the 1/16" - 3/23" steel skin of the bus. Is it possible to get a more powerful antenna for it?

  3. I really like the sounds of the “authorized list”. I’m new to RFID. Does that mean if someone were able to get close and copy your card that they still wouldn’t be able to get in?

  4. From what I’ve read 125khz is the right frequency for what i’m trying to do? Am I right on this, or would another frequency penetrate the steel skin better?

Thanks for any insight.

You will need to make a “window” of plastic/Fibre glass/ basically something non metallic

Hopefully this video, it should answer most of your questions

see above

Unfortunately not.
if they copied your card, for intents and purposes, and as far as the bus is concerned, the card holder is you.

Is the possibility of somebody copying your card a realistic one?
If so, you may have other concerns :wink:
You could get another RFID access system, that only takes specific HF non cloneable cards…
There will be something out there, but the ones I can think of off the top of my head, there would still be a way to make entry if they were determined.
I guess my threat model is different from yours.

Yes, for the xEM Access Controller.
basically any T5577 card will work for this when it is put into the right mode.
The xAC comes with a couple of fobs, but if you want more you can simply enroll them, although if T5577, you will need something to change the mode to EM. Like a ProxMark3, a Flipper zero or a white or Blue cloner (the last 2 I don’t normally reccomend, but it will suit your purposes here)

This :arrow_up: may all sound like gobbledygook, but trust me you’ll be alright, just come back here if you vet stuck, and one way or another we’ll get you sorted.

Otherwise somewhere like Aliexpress you’ll be able to pick up some spares and in any format you want.
Wrist bands, fobs, cards, rings…
A Magic Ring will work, and if you want implants, xEM, NExT Implant etc will work.

Also feel free to share your project when you are done, we would all love to see it, just share in #projects

Any more questions, just fire away

To to expand and further clarify on this point, I think the xEM xAC can store up to 20 users, but in reality thats 20 UNIQUE users, the number may be 20 but you could actually issue out unlimited card of a single user…if that makes sense…it doesn’t change the answer though

Here they come :wink:

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Hi Pilgrimsmaster,

Thanks a ton for the replies! Much appreciated.
I was just coming to change the original post to say it’s probably closer to 1/16" or 3/32" in on the skin of the vehicle.

Making a window really isn’t an option…
I might have to just go to a regular style lock if that’s the case. Bummer.

I’m not sure about how things get cloned? I was under the impression that they just had to be in close proximity to you?

Would the 13.56mhz do better through metal? I’d read that 125khz could go through thin metal?

All locks just keep the friendly thieves out. It’s a vehicle and has windows, so there’d always be alternate ways to enter…
Not sure what you mean about threat models, but people breaking into the buses is a definite things, and happens often.

Thanks for the info on the proxmark 3. I was hoping to skip that learning curve. Looks like you can get one with the better firmware already installed, so maybe that’ll help.

Oh, and I’d already watched that video, thanks! That’s what made me wonder about the strength of the antenna.

Sounds like I might have to go another route though.
I’ve really been looking forward to completing this project.

Thanks for the help.

Sorry, I don’t speak gibberish, I have no idea what that is…

Behind an indicator? Glass? Wing mirror?
I am going to track down a relevant video for you and somebody else that posted the other day, I’l be back with that after this reply…

With the right equipment and more importantly knowledge that you have one and the intent to use it…

No, not really, probably worse infact. The 125kHz ( Low Frequency = LF ) might, possibly, maybeeeeee? Through thin aluminum ( FYI Pronounced a·luh·mi·nee·uhm ) with a full sized card


Yeah fuck that for a game of soldiers, If you don’t need it, don’t bother…You should not need one.

Yeah, It is good. AKA good with implants and key fobs, even better with full sized cards…

I think you are on the right track… Consider the alternatives above ( wingmirror etc ) and I’ll be back shortly with another suggestion.

In the interim, if you can take a photo or short video of the bus door and surrounding areas, we all may be able to give you some suggestions,

Oh, and learn the Metric system for fuck sake :wink:

This is about an hour long, but worth a watch, practical guy with practical solution…he also gets an implant at the end which is interesting

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Metric system schmetric system. I flunked that in school :rofl: :joy: :sweat_smile:
(adds more confusing fractions…)

Thanks again for the help. There’s hope!

Oh, one more thing. I know there’s been a system around for years on the corvettes. Where it unlocks when you bring your fob close to it. No need to push a button or anything. It just unlocks. That’s got to be similar right? And RFID??

My brain is hurting, haha, I should take a break…

Appreciate the help

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There are a number of cars now with those proximity type system built in OR you can after market install one yourself, it would be more secure, BUT I really think the xEM xAC will be perfect for what you want to do, and “simple”

But if you want to home brew a similar proximity one @turbo2ltr made a fantastic “hack”

I have a couple xac systems

They have some of the best read range I’ve seen for implants,

I think I have a stop sign floating around I can try to put it in between to see if it reads, but I’m guessing no
edit confirmed, will not work

As for the comment above, like the corvette systems… no it isn’t going to work like that, those are active battery powered fobs that are always sending out a signal for the car to find

Implants are passive, no battery, and are for all intensive purposes are dead until within the 1” range of a reader
(That’s like 2-1/3 cm pilgrim)

Also it’s worth pointing out, the xac doesn’t provide any meaningful power, so you’d need to pull power from the bus to power the xac, and to power whatever the xac controls

Something I always forgot

Much appreciated Eriequiet,

I’m not currently doing an implant, but a ring and several wristbands, but I’d guess the strength and range is about the same?

The bus is going to need to power?? The power supply for the system? It looks like 110v to 12v for a lot of them? But the one I was asking about looks like it takes 12v? I’ll have a pretty massive solar system on the bus, so power shouldn’t be an issue (4000 watts).

I’m still curious about trying to increase the receiver power? I have a system I got that’s from germany with what looks like a pretty robust antenna. It’s also 2 wire. Could I replace the antanna on the Access Controller V2? Or is it dependent on how much power is going to it from the board?

I couldn’t get that system to work for a number of reasons, but I’ll fire it back up and see if it will trigger with a piece of metal between. Good idea.

Thanks for the feeback, much appreciated.


Wow THAT is a BIG bus



Thanks for the info Pilgrimsmaster,
I’ll have a look.

Something should work :slight_smile:

P.S. Here’s a pic of the bus door area. Current plan was to put it about where the red mark was.

A couple of ideas jump out at me

Behind the rubber strips

Behind the indicator ( May be some issues, but worth a test )

Behind the badge…but I guess it is Aluminium :shrug:

Behind the glass / Perspex on the door

It looks like you are putting another skin on the door ? So you could enclose the whole access system behind it. you will just need to run power carefully ( easy ) from the hinged edge

Just some quick thoughts

So, it just kind of dawned on me, that a window doesn’t have to be a window? Right?

So, I could make say a 2" (5cm for you) hole in the side of the bus and cover it in fiberglass?
And putty and paint over it? So it doesn’t look different from the rest of the bus? (isn’t obvious).

Then the signal should be able to pass through it with no issues right?

I could even put/imbed the antenna for the Access Controller V2 right into the patch maybe?

I think that could work right??

:thinking: :thinking: :thinking:

Ps, those are great ideas, thanks!

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You answered your own question

It’s actually used in some RFID blocking wallets aka HF 13.56MHz like what your credit card uses.

Because it is conductive (similar to copper) it can act like a Faraday cage.

Thanks, I deleted it but too late. Looks like I can get some metal repair epoxy/resin that will work.

I’m thinking I can pull this off now.

Thanks a ton! I’ll put up some pics or a video of the finished result. Excited!

For what it’s worth here’s the antenna you’d be dealing with

The black plastic is just a face plate I printed for my safe

You could just drill a tiny hole and run the the antenna through and make a tiny little plate like mine

Unfortunately it doesn’t really work like that,
It’s a combination of factors that need to be balanced with each other

Antenna size of reader, antenna size of fob, power, tuning etc

It’s a super complicated black magic,… there’s only a couple people here that could even explain it, let alone try to make a system have more range

The xac is pretty great to begin with, take what you can get lol