Help with designing a safe/money box

Discussion in 'Homework Help' started by JackMaahn, Oct 7, 2015.

  1. JackMaahn

    Thread Starter New Member

    Jul 3, 2015
    I am designing a money box for my coursework on Circuit Wizard but I need help with designing the circuit, making it lock and programming the circuit. The idea is that when you enter any code, the money box will open regardless of the code. I want to program my circuit so that when a key is pressed, the number that was pressed will be displayed on one of the 7 segment displays and when 3 keys have been pressed and 3 numbers are displayed on the 7 segment displays then i want a solenoid to unlock my money box. The money box is designed for educational use for children so that is why it doesn't have to be secure.

    If you can help me with this I would be very grateful, any help is appreciated!
  2. pwdixon

    Active Member

    Oct 11, 2012
    You will need to be able to reset the counters by connecting a processor output to the reset inputs.

    You also need another digital output (that I'm not sure you have available) to drive your solenoid, which will need something like a fet transistor and a flyback diode across the solenoid to suppress spikes. I would also suggest you might put an LED in parallel with the solenoid as a visual indicator of 'unlocked'.

    You will probably need resistors on all the counter outputs too to limit LED current.
  3. ISB123

    Well-Known Member

    May 21, 2014
    You cant use a MCU?
  4. pwdixon

    Active Member

    Oct 11, 2012
    Looking at this Genie system I would guess that the OP doesn't have enough experience or perhaps the time to learn how to use a micro, this Genie system looks like a rapid/simple 'get something working' thing for people who have little knowledge of processors. Having said that an Arduino might have been even easier and potentially would have had more I/O available.