Controlling 20+ coin motors with a microcontroller

Discussion in 'Embedded Systems and Microcontrollers' started by bpatrick, May 20, 2013.

  1. bpatrick

    Thread Starter New Member

    May 20, 2013
    1
    0
    Hello,

    I'm fairly new to programming and microcontrollers so some of these questions may seem rather basic, but what I'm trying to do is get 20+ 3V coin vibration motors (model no. 310-113) to vibrate in different orders depending on a users input. Sometimes the output may need 1-9 motors to vibrate at the same, sometimes 5 in a sequence.

    The speed or direction isn't really a concern as it's just for the vibration. As I said I'm new to microcontrollers so was probably going to get an ATmega2560 compatible with Arduino.. so the first question is do I need to find driver circuits for the motors or can I run them direct from the board?

    If I need driver circuits, what would someone recommend in this case? If I don't need driver circuits, are a diode and resistor still needed?

    Any suggestions would be great.
     
  2. Litch

    Member

    Jan 25, 2013
    86
    7
    So I dug up a datasheet for these things and their normal operating current is 63mA - well within most microcontroller individual output limits...

    BUT - if you required all 20 of these running at once, all of a sudden your total collective current draw through the uC is 1.3 Amps. Pop goes the weasel.

    As such, you'll need a control circuit - look up ULN2803A darlington IC - you're best using the IC as a sink (+ve from power supply goes to the motor, -ve from motor to the Darlington, Darlington controls the path to earth).

    You'll also need an IC with 20 I/O pins... OR (preferably) - a uC with an I2C port and a bunch of PCF8574 I/O expanders.

    I'll throw together a schem in a sec.
     
  3. Litch

    Member

    Jan 25, 2013
    86
    7
    Schematic attached.

    TODO:
    * Power supply
    * Revise voltages, add resistors, capacitors, etc...
     
  4. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Connect pin 10 (COM) to the positive supply, not ground.
     
Loading...