motor delay circuit with timer

Discussion in 'The Projects Forum' started by jtstech, Jun 4, 2010.

  1. jtstech

    Thread Starter New Member

    May 28, 2010
    2
    0
    Hello everybody. I would appreciciate any help you can give me. I am working on a project that will require 2-4 AA bateries and a very small rc type motor. Any circuit would have to be rather small (1 1/2" X 3 1/2") if possible.

    Requirements:
    30 second motor delay afer powering on.
    Motor to run for 30 seconds or 1 minute and turn off.

    Optional:
    I think it would be great if I could incorporate a dip switch to control different motor run times in increments of 30 seconds.


    I dont really expect for you deseign the circuit for me, but would like a push in the right direction.

    Thanks soo much
     
  2. Bychon

    Member

    Mar 12, 2010
    469
    41
    Here's a push in the right direction. The circuit is rather easy. The hard part was in finding a chip that will operate at low voltages, have rail to rail inputs, and deliver considerable output current (35ma @ Vcc-.5)

    The chip is in stock at Mouser for $1.90 plus shipping.
     
  3. jtstech

    Thread Starter New Member

    May 28, 2010
    2
    0
    thanks Bychon,
    i have little schematic knowledge and am still trying to dicypher the drawing. I just havent had much time but I am sure that it will help out alot. I appreciate your help.

    Thanks
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    I've messed up Bychons nice simple ckt with some numbers. What a nice dual OP-Amp. If built , would use a 1 meg. pot to set up timing ,then replace with fixed R. Guess timing will be around 2.5 RC. I believe a LM393, with 2.2k pull-ups would also work, same pinout. Would help to know more about motor to select drive ckt, Was used with a tape drive motor as shown, drawing about 50mA.
     
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