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Custom Key RF transmitter

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  • Custom Key RF transmitter

    I have a peugeot 406 coupe 1998 and the key fob is well worn. It still works but id like to replace it with a new one.

    I have a PIC, oscilliscope, rf, and RF kit.

    Just now i have the key fob opened. Attached are the pics...

    I thought it would be just a matter of finding the RF oscillator and scoping the data input to it.

    I thought that this would be a serial stream of bits of some kind, that i can store and then replicate in a PIC.

    But after i scoped the CAN shown in the second picture, all i saw was a SINE wave of about 10mV that trailed off to 0 after about 6 periods.

    Surely this isnt the output stream is it?

    Has anoyone got any idea's on how to intercept the data send by my key?


    Note that the ICs shown are just what i think they might be from reading the packaging.
    My stupid paint program wont type out the letter A or 8 so i had to replace a with @ and 8 with the string 8. I hope you understand what i mean
    Attached Files
    XBOX Civic- dcdc converter, 7.2" touch lcd, Evox, Gentoox, 160 gig hdd, Wlan on the way, Custom Paint job

  • #2
    Forget all about reverse enginnering key fobs.
    Key fobs use rolling codes to prevent nearby car thieves from reading the code with an RF-scanner when you press the unlock button and then be able to use this code afterwards.
    If the key fob actually did send the same code each time the key was pressed then it would be way too easy for thieves to break into any car they wanted to.
    Rolling code
    From Wikipedia, the free encyclopedia
    Jump to: navigation, search
    A rolling code (or sometimes called a hopping code) is used in keyless entry systems to prevent replay attacks, where an eavesdropper records the transmission and replays it at a later time to cause the receiver to 'unlock'.

    Such systems are typical in garage door openers and keyless car entry systems. The most widely spread algorithm for code hopping systems today is KeeLoq..[citation needed]
    More in depth description of how rolling codes works and how car key fobs are reprogrammed
    How Remote Entry Works

    Some microcontoller specific reading about rolling codes:
    Atmel AVR application note AVR411: Secure Rolling Code Algorithm for Wireless Link
    Microchip PIC with KeeLoq

    You are probably best off buying a new original key from your Peugeot dealer and have them progamming your car to pair it with your new key.

    Here's how to re-synchronize a key if an already programmed key has lost synchronization with the car:
    PEUGEOT 406 PLIP - Remote Key Programming
    Auto Car Key Transponder Services

    For some cars specialist hardware is required to re-program the vehicle keys.

    The normal course of action would be to use your main authorised car dealer but this can prove very expensive.
    Luckily, there are numerous auto locksmith companies available offering re-encoding other than using your main authorised dealer.
    There are companies that will produce master keys or re-encode your transponders. If you've just lost your keys and your car is parked where it will attract fines or even removal calling an on-site auto locksmith specialist is probably your best bet.

    Before you call the company check all your car's paperwork. Most cars have a code card supplied when new. Check your car's manual and service book folder for this. This code may be required when creating new master keys. The alternative may be far more expensive so make a thorough check for this information.
    hi there,i am a peugeot mechanic and do this procedure all the time it does not programme the key it simply sinc the key to the car if the car starts with the key its programmed all get a key programmed you must plug the computer at peugeot into th the car and can be costly.the instructions you have is to sinc the key the easy way to do it is put the ignition on hold the big button on the key in for 30 sec let button go pull key out and try it if it doesnt work there could be a fault with the receiver on the car.the key and the remote work like a tv remote same principle. hope this helps best of luck.Brian


    • #3
      just use something like this and save yourself the hassle
      Scion CarPC

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