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Keypad car starter

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  • Keypad car starter

    Hello im a newbie here. Im spanish, and sorry for my english.
    I search in the forums a thread about this but ive some questions.
    I found this searching in google:

    5 Digit Alarm Keypad
    Its possible to use for start the car??? And how much power (Amps) need the relay for support the cranking?? What do you think about this system??

  • #2
    Thats a pretty cool idea.. but it looks like you would have to do a lot of modding to get it done.... I am not that fluent in electronic lingo like this schematic but I think it could be done.
    New CarPC on the way again I think. I miss my old one!!!


    • #3
      R3l0ad is right. it could be done but would take a lot of work. First of all, you need several things to happen when you start a car. You need to have power at ignition, some car have 2 ignitions, then power to the starter, and the most important part is sensing when to stop cranking. You would be better off modifying a remote starter for a alarm. If you are interested, there is usually two easy way of knowing when to stop cranking. One would be using the coil terminal to sense when the motor is running. You can read some voltage at this terminal when motor is running. Another way is to sense vaccum. All said and done, I would'nt do it. There's too many stuff that can go wrong. If something goes wrong your life could be on the line.
      66 Mustang


      • #4
        Ive a another question, when you put the correc key in the keypad, realay stays on? or only stay a few seconds? Because you can use it for power the car and later use a button starter, is this possible.
        And other litttle question, i can use it for start the pc, is for try the keypad.


        • #5
          Good idea.... but I don't think what you are trying to do has been attempted before... and if it has I don't think it has been successful yet. Try maybe...

          I think umsam has a good idea, try modifying a remote starter... that is going to give you everything you'll need... you could simply create a keypad that has a remote device built into it, and when you press the proper code it will send the signal to your car... then you don't need to run any wires except from the battery to provide power.

          That wouldn't be too complicated because basically you would be creating a glorified remote.
          New CarPC on the way again I think. I miss my old one!!!


          • #6
            Yeah, the keypad provides a constant switched voltage. Like you suggest, better idea would be to use it to control the electrics then use a button start.

            It seems like it would work. the keypad basically takes a 5 digit code, once this is keyed in it gives +12V out when keyed in a second time it gives +0V out. Essentially it is simply toggling the output between +12V and +0V. Pipe this voltage to a relay and you have a switch controlled by the keypad.


            • #7
              Okok. And how much amps need the relay support, because a battery car gives a lot of amps no?


              • #8
                For you relay question, for the ignitions you should be fine using a regular 30/40 amp relay, you can find this at any automotive store. For the starter, use what is require by the car. Newer cars have relay activating the solinoid to the starter. Older cars are done mechanically thru the ignition key switch. I done hundreds of starter kill with 30/40 Amp relays and never had a problem. Make sure you use name brand like Bosch or Siemens for they don't fail prematurally. For a computer power on/off setup will be fine, only thing is I don't think you want to cut the power to the computer, you want to do a shut down.
                66 Mustang


                • #9
                  heh my friend did this mod on his civic... however he never changed his code too often so the numbers on the pad wore out and u could tell which numbers were in his code.. just press in a few different combinations and u got the car started.. lolz