Proximity Car Key, RFID mod

for dropping from 3.3 to 3 you could use a voltage divider. The keyfob doesn’t use much power so any loss is minimal. Here is a calculator for that

Alright, prototype in a working state. Still need to tinker with the simple ac code to get it to do what I want. but card is read → on success key gets power, car unlocks… huge fucking win in my book!!

Next steps

-understand how to remove these two buck converters from the project
-modify code to deal with both inputs(car off/ car on)
-wire up other buttons like unlock and trunk

  • 3d print enclosure
    -maybe come up with a pcb?

Kind words there dev. Here is our simpleAC

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Alright the prototype is in a working state!! Key is wired up, the thing talks to me when you use it, all the voltages are correct, and It functions as intended!!

Next step after this is to figure out how to wire it in from the car.

Mock the ignition wire so I can get fancy with the programming

Scale this thing down somehow?? Way outside my area of expertise.

Print an enclosure and install

If anyone can point me in the right direction with software/ resources to make this thing smaller I’d be super grateful

You could make it smaller and permanent with protoboard and an enclosure. I expect the only thing you really need to integrate it into the car is a 12v to 5v regulator/buck converter and attach the antenna somewhere. As for the software I have no idea.

Also, I would use a little bit of hot glue to secure the wires going to the remote.

Alright feeling like Alice at the moment. Learning Kicad to scale this puppy down, and possibly create a PCB from this thing.

If anyone can read these things or have any pointers I’m all ears. This is my first electronics project as well as the first time I’ve opened a CAD program. Pointers are welcomed.

Here’s the Kicad Files if anyone wants to look around


Also thanks for the recommendation, I did end up using some hot glue, and feel alot better about the key. It was feeling a bit flimsy.

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It’s been a month so I figured I’d give an update. I’ve been putting this whole project on the back burner for a few weeks. Between work, my plex server panicking, and visitors in the house, I haven’t had a second to get back to this one. Fingers crossed I’ll get some space to breathe in the next 2-3 weeks.


Can i assist ive already been on this for 2 years

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surprised you’re still following! Welcome back and thank you for the ping.

I’m still at the “need to finish a pcb” stage. Does the simple sexy now support key fobs?? cause that would be awesome.