Adding keypad security to your automobile’s ignition system

[BadWolf] managed to make some free time to get back to his own electronic projects. This time around he’s created a security system for his car. It’s patched into the ignition, preventing the engine from starting when the key is turned. A driver must first insert the key, then type the combination on a keypad in the center console before the car will fire up.

While he was working on the project he also decided to add a start button to the dash-board (we think it does make it look like a later model vehicle). The keypad is driven by an Arduino Nano which has the start code stored in it. Power for the system is provided by a USB hub hidden behind the dash which he thinks will also come in handy with future hacks.

When the proper code is entered, you’ll hear a rendition of the Super Mario Bros. theme. The speaker also lends a pleasant beep with each keypress. See the demo clip after the break to hear it for yourself.


  1. Skeltorr says:

    You can buy this from china, it came with my alarm.

  2. xorpunk says:

    transponder keys with discreet challenge/response protos and rolling code dongles are still the best things for security. Italian makers just add laser cut keys and sat tracking to that..

    • NATO says:

      No, those are even easier to thwart – You simply need a set of transcievers to extend the range of the key – Get transciever near owner -> get other transciever near car -> car unlocks. Start car, pull it on to trailer, take it away…. Or, I assume you can simply duplicate the signal that is being extended, and the car will run for some period of time…

      Worse yet, if it’s a simple RFID key, then it is much easier to simply copy the key by walking by with the correct RFID reader, punching the ignition, and driving off…

      Newer cars are easier to steal than older cars – You don’t have to cut and splice wires anymore.

    • NATO says:

      WOW. Just looked at his schematic – So to bypass this system, you need to rip one wire out and connect it to a voltage….. There is no point if you are going to make it that easy!!! This is for fun, not to actually make the car harder to steal.

      • Ales Hakl says:

        Even professional car security systems can be bypassed by pretty simple means. Point is that the system does not have to be secure, it only does have to inconvenience the thief enough so the added risk of bypassing the system is not worth it for the thief. And for that, even completely trivial homebrew solutions are mostly better as security through obscurity is pretty important factor in this.

      • Badwolf says:

        for you’re info Nato,yes the system can be bypassed by shorting 2 wires together. Having seen a report about thief having less than 5 min to steal a car,it’s not very likely he’s gonna rip off the dashboard and try to understand the mess of wire down there with jumpers and stuff to make it start. Point is,If i give my key(with transponder in) to someone,they won’t be able to start the car. So I got no problem lending my keys to a drunk buddy looking for a place to sleep for the night as i’m 100% sure he’s not gonna start it,police proof also if they accuse you of “wanting to commit drunk driving” If ya don’t know the code,they are screwed. ;)

    • NATO says:

      Well then, badwolf… It sounds like you aren’t very *bad*…. (drum roll please)

  3. Alexander says:


    And now we all know his keycode, which makes this keycode useless.

    Which is why all demos are done with the keycode of 12345

  4. aztraph says:

    what the hell is the mario tune doing in there? Awesome!

  5. Badwolf says:

    The keycode has been changed right after video.
    Also,didn’t you notice the shape of the password..;)

    Glider someone?

    It is by far more secure,but it’s really expensive to get that to a vehicule which didn’t came with it at first.

  6. cptfalcon says:

    Wow I never expected to see someone else use bike chain for a key chain.

  7. Anybodysguess says:

    It will be cool for about 1 week < then it will be extremely annoying.

  8. Hal H says:

    So just like in the movie Transporter huh?

  9. Mike says:

    Nice looking build, it looks like something James Bond would use. Which button activates the ejector seat?

  10. draeath says:

    Someone mangled a tag. I don’t think this qualifies as “anit-theft” – perhaps “anti-theft” though?

  11. ferdie says:

    This is perfect against drunk driving drunk try the code, but once again or even better to remember to lock in combination with a lock to blow in to measuring alcoholic

  12. The Asshole says:

    It was way better if he stoped using the key and used remote unlock for the door and start/stop button for the ignition.

    And even better if he just used a CAM to compare the numbers inserted, instead of a arduino.

  13. jason says:

    Nuff’ Said…

  14. gs611 says:

    12 volts to 5 volts with a lm7805, how about the heat dissipation problem? IMO, I would have gone with a low drop out regulator especially if you are powering that usb hub and plan on using anything in addition to the arduino.

    also the website says that the wires will be complicated enough to confuse a thief. I beg to differ, this may stop some 16 year olds who wouldn’t be going after a prius anyway but again, my opinion ;)

    wouldn’t be a complete review if I didnt give you props…
    Good job overall, the install looks clean, I especially like the tubular lock on the panel next to trunk popper (though easily defeated in seconds with a southord lock pick)

  15. Marc says:

    Is there a way to bypass it (when the arduino dies from hot/cold weather, dirty car power or any other of the 1000s reasons this could fail)?

  16. zrzzz says:

    10/10 for coolness, but what is that? an ’82 Datsun? That’s a theft prevention device all by itself! =D

  17. Hey, maybe not applicable to hack this car keycode, but still very interesting way to steal a keypad PIN code:


  18. Estoban says:

    Subaru have had a system like this for a while. It gets tedious when you have to work on 5 or so a day. A good feature is ‘valet mode’ though which gives you 10 starts before you need the code again.

  19. Bigdeal says:

    I see so many reasons why this is bad:

    1) As someone said, your car can be hotwired

    2) You exposed it on the internet, so high-tech thieves might actually find this fun

    3) Imagine you’re in a danger situation where you have to start very fast, or your engine stalled in the middle of a very busy place… good luck avoiding that truck

    4) If the circuit can be accessed somewhere, Arduino code can be replaced with some other code that won’t check for a keycode

    Kudos for the hacking and getting your hands dirty, nice that it works, but it’s a terrible idea to mess with a car, so many things could go wrong and end up killing you.

    • Badwolf says:

      Don’T forget,the key is still needed to run the car,which still involve the ID chip in it. A thief would still have to bypass it too,so it’s not replacement security,it’s added.

      • If your key has an ID chip in it, I’m guessing this project was more for the fun of just wiring everything up than it is a practical theft deterrent.

        If I looked in your car and saw that system, and then saw that the car wasn’t very clean I’d probably break the window, rip up the control panel, and then just leave it there like that… you know, if I was a criminal. I think you are asking for trouble with that system.

        Sometimes the best anti-theft system is a silent one. Most crooks would know your car has an ID chip and would stay away, or steal something that was worth big bucks instead.

  20. henry99 says:

    Just rip off the plastic panelling next to the gear stick, there will be 4 wires, the two for the ignition, and 2 for the battery. Just connect the 2 ignition wires together and jimmy the ignition as normal.

  21. Al says:

    Nice, if you add security entry system and a key power disconnect in a hidden location it would greatly improve the system. Like this one from McMaster Carr. Keep hacking!

  22. Anonymous says:

    Reminds me of bmw 7-series ~1988. Their keypad lock’s called OBC.

    • Dominic49 says:

      the OBC “on board computer” has a code function where when you shut the car off but had yet to pull the key out you can press the code button and enter a 4 digit number. upon return to the vehicle you would need to put the 4 digit code in otherwise the car will crank and crank but never start. they put it in all the cars of the era with the full featured OBC including the 3 and 5 as well.

  23. Salomon says:

    this car is manual, so a thief could turn it on, by pushing it down a hill in 2nd gear…

    • Estoban says:

      No you couldn’t.

      • onyxphase says:

        Technically if it is a manual shift transmission, and you were able to get the key into the run position. you could bypass his system of starting the car. Seeing as it’s a new car, the key would be chipped anyways. With the key you could still get this car rolling, as this just prevents you from turning the starter motor. The starter can be replaced by a slight downhill slope, or a strong friend.

    • 3nigmat1c says:

      Don’t forget, the steering wheel lock, true he could pop the clutch and get the car started w/o the key (maybe) but you need the steering column unlocked to steer. I know this is at least true for older cars :/

  24. john says:


    got it

  25. William says:

    The Tesla Roadster has this built in from the factory. If you don’t have either the key or the pin code you can’t disarm the alarm.

  26. D-Rock says:

    Dear HOD commenters,

    I get it! You’re so very smart and you would have done it so much better. Great make a video of your improved project. Until then, no one cares. Do or do not. There is no I would have done it better.

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