PIC servo control

Discussion in 'Embedded Systems and Microcontrollers' started by clichtenberg, Jul 16, 2010.

  1. clichtenberg

    Thread Starter New Member

    Jul 16, 2010
    I'm working on a project that uses a PIC16F84A to control two servo motors. I'm writing the program in assembler. I'm having trouble figuring out how to interface the PIC with the motors. Does anyone have any experience controlling servos with PICs? Any good references would help a ton as well (I haven't found any yet).
  2. bertus


    Apr 5, 2008
  3. clichtenberg

    Thread Starter New Member

    Jul 16, 2010
    Thanks for the quick response!

    The site helped with figuring out some of the interfacing, but I'm still not sure how I would go about writing the code in assembler. Since my project involves using the two motors to essentially open a box (I'm building a leave-me-alone box: http://www.youtube.com/watch?v=RMGJB410Ccs), I was considering having interrupt routines for when the switch is flipped. When I flip the switch, one motor should open the box, then the other should flip the switch off. So, I think the entire process would be, wait for the switch to flip; when it flips, the hatch motor should activate and open the hatch and the motor with the arm should flip off the switch, retract the arm, and the hatch motor should close the hatch; then the process would repeat. Yes, no? Am I on the right track?
  4. Markd77

    Senior Member

    Sep 7, 2009
    Not too far off. You probably need a little (maybe 1/2 second) delay between open hatch and flip switch.
    Because you can adjust the hardware you could get away with very simple code for the servos:
    wait 19ms
    both servo control signals high
    wait 1ms
    maybe turn off 1 or both servo control signals
    wait 1ms
    turn off both signals
  5. MMcLaren

    Distinguished Member

    Feb 14, 2010
    I suspect if you design the "arm" correctly you could use a single servo to both open the lid and turn off the switch...