cd4017 Code lock

Discussion in 'The Projects Forum' started by xile6, Jun 19, 2011.

  1. xile6

    Thread Starter New Member

    Jun 9, 2011
    Ok so i was looking around for a electronic code lock.
    Ended up find this. Attached below.

    well it uses a cd4017 which i never worked with before. I understand the diagram. I just have some questions.

    first do i have to use Q1-Q9 and output on Q10 or can I make my code shorter and just use Q1-Q4 and output on Q5?

    Also i can wire all the non-code keys to S10 for reset? So if the wrong key is pressed it will reset the chip.

    And can i use a 2n3904 transistor? The diagram calls for a sl100 which i am having problems finding. but i have about 100 2n3904.

    thank you for any answers you can give.
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    Yes to all.

    Here's the complete article:

    You can use a plugboard type set of connections to change the code without moving or rewiring switches.
    Last edited: Jun 19, 2011
  3. xile6

    Thread Starter New Member

    Jun 9, 2011
    yes i have that pdf just didnt know how to post it.
    what i really want to know is do i need to use all 9 for the code or can my code be 4 long and just output on 5?
  4. Pencil

    Active Member

    Dec 8, 2009

    Here's a datasheet for the 4017 if you do not have one.
    Last edited: Jun 19, 2011