A circuit to solve the following problem

Discussion in 'The Projects Forum' started by newbiecircuit, Aug 26, 2008.

  1. newbiecircuit

    Thread Starter New Member

    Aug 26, 2008
    I am 18 and new to electronics. I need a circuit(s) to solve the following problem: I have a system of 8 parallel inputs (switches) 0-7 which control 8 parallel outputs (low voltage servos). I want to be able to press any combination of switches, ie I press switches 7, 1, 6 & 0 and servos 7, 1, 6 & 0 are activated in that exact order, when I hit a 'GO' Button, ie I have pressed my 4 switches 7, 1, 6 & 0 and on pressing 'Go' once servo 7 is activated, press 'Go' again 1 is activated etc. So, my input switches are like pre selectors which decide what corrosponding servo will active on hitting 'GO' and in which order. I would also need a 'Clear' so I could start again. I am swamped by the information available, do i go digital or analog? Do I need ADCs, encoder/decoders, logic gates, memory circuits etc? Can ANYONE answer this. Please HELP!
  2. kammenos

    Active Member

    Aug 3, 2008
    It looks like a work for microcontrollers... With simple ic this is not very easy.
  3. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    Are the switches momentary action and are the servos standard RC types?
  4. RiJoRI

    Well-Known Member

    Aug 15, 2007
    "Do I need ADCs, encoder/decoders, logic gates, memory circuits etc? Can ANYONE answer this."

    OK, take a deep breath, and calm down! Don't panic!

    First, the digital/analog question. If a problem deals with two states (ON/OFF, GO/NO-GO, FULL/EMPTY, DO or DO-NOT) the easiest method is usually digital. Analog is better for KINDA-FULL, ALMOST-EMPTY problems. (I'm simplifying.)

    Next question is "What kinda stuff do I need?"
    First you need 8 inputs, and 8 outputs. They will need to be "conditioned" depending on your hardware. You also need some kind of memory to keep track of what has happened. These requirements point towards a microcontroller, unless you are taking a class where the instructor has said to use logic gates, or PALs, or FPGAs or something other than micros.

    Sit down and sketch out a rough block diagram of what you want. Switches, and lines going into a box representing the micro, and lines coming from the micro to the motors. (Yes, dear readers, I am aware that more "stuff" will need to be added. We're just looking to see how simple this really is.)

    Now you will need to go on a hunt for a microcontroller. It will need at least 16 I/O pins, but not a lot of memory. I would look at an 8051-derivative (many mfrs.), or a Microchip PIC, or an ATMEL AVR chip. Look around the mfrs web sites -- they have selection guides and users groups also. Design kits are good for this -- you can get up and running without the hassle of having to learn how to connect the micro and program it -- it comes pre-checked and on a board.

    Good luck!