A-Z of car ignition systems



  • so bought most of my components today and started work on the prototype board
    looks horrible i know but its a start.

    gotta wait for my reader and arduino to arrive before i can put it into full gear....
    i will post the breadboard representation of the work im doing as well so that people can see what actually to put where instead of my mess of components and wires

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  • Community Helper

    Good stuff mate. With toner transfer you basically clean the board, print a reversed version of your pcb file onto normal paper, then iron it onto the board with a hot dry iron.
    Once it's cool you soak it in water until the paper degrades and falls off, then etch what remains.
    They can turn out very nicely if you take your time with it.



  • @lokki as a bonus the guy at the TAFE near me has said i can use there lab to build boards if i want, so i got all the gear i need to do full photo PCB so hey why not if you can :D

    on a slightly sadder note i tried to imporve the schematic to use more closly related parts for my PCB design and i think i broke the schematic....would it horrible of me to ask you to double check? i think its in the on relay....i reveresed the diodes like you said, but i think i did something really wrong...

    project file 2
    it seems like power is just flooding all the links now


  • Community Helper

    What kind of transistors are you using, mate?



  • @lokki BC327 PNP 50v 800ma
    the ones in the schem are just the ones either you or i dropped in there because they fit


  • Community Helper

    Ok, this will be the issue. The transistors I use, simply because I've got a bag of a few hundred from building nixie displays, are MPSA42 NPN transistors.
    If you're going to use PNP you have to reorganise things and put your switching on the positive rail, pull_up_ resistors and reverse the logic coming from the arduino.



  • @Lokki sorry my bad im a little dyslexic at this end of the day...NPN transistors
    disreguard everything i said i dont even know why thats on the receipt that way, ill look at the actual trans

    BC549CTA



  • found this
    as a possible simple latch relay....less posts and possibilitys for error perhaps?


  • Community Helper

    Try substituting the relay coils for leds in the correct orientation to see what's happening there. The schematic looks ok to me, it may just be something you've done when you've laid it all out.



  • Cheers. I though somehow that when I swapped the orientation of the diodes I might have stuffed up the work you started. If the scheme is correct I'll work on building a board



  • lol making the threads for the PCB is actually fun...its like a puzzle game.

    im not getting a good score yet, but if i keep trying ill win eventually

    :D


  • Community Helper

    lol. It's awful isn't it. especially when you're making a single sided board.
    Single sided boards are more art than anything else. Double sided is a bit of a cop-out really. It's routing everything without using too many jump links on single side that is the real work of circuit design.



  • so the arduino arrived today..pretty flashy looking....still got to finish my PCB design....having issues as i dont have the final relay yet to make sure my measurments match


  • Community Helper

    Just make sure you breadboard it first. It'd be a pain to get a board made up and have to change it.
    fyi I was doing a funky thing with diodes in mine to add extra powered outputs and ended up burning them out on a main road. Instant loss of car power and a panicky moment in traffic.
    I really shouldn't have used diodes to do that with, at the moment I have wire links in the same place and it's fine.



  • will do @Lokki

    i think i got the code wrong somehow...

    This report would have more information with
    "Show verbose output during compilation"
    enabled in File > Preferences.
    Arduino: 1.0.6 (Windows NT (unknown)), Board: "Arduino Uno"
    sketch_oct10a:13: error: 'PN532_I2C' does not name a type
    sketch_oct10a:14: error: 'PN532' does not name a type
    sketch_oct10a.ino: In function 'void setup()':
    sketch_oct10a:23: error: 'nfc' was not declared in this scope
    sketch_oct10a.ino: In function 'void loop()':
    sketch_oct10a:56: error: 'nfc' was not declared in this scope
    sketch_oct10a:56: error: 'PN532_MIFARE_ISO14443A' was not declared in this scope


  • Community Helper

    Looks like you've either not installed the NFC libraries or you've got it slightly wrong, dude.
    the pn532 libraries come with 3 or 4 sub folders in the main folder, you have to copy the sub folders into your arduino libraries and disregard the main folder.



  • Is there any other NFC reader or a good way to separate the antenna from the board?
    I'm thinking it would be pretty neat to have my car start when I rest my hand on the shifter, but obviously the whole board wouldn't fit on there.


  • Community Helper

    In that case @jaar I think @MrStein is the one to talk to. He has an NFC enabled arduino under development which will allow you to use an external antenna.





  • @lokki dodgy usb cable with the aduino