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2 motor 4 pin control — Parallax Forums

2 motor 4 pin control

be80bebe80be Posts: 56
edited 2008-10-17 15:58 in BASIC Stamp
Is there any way to control two motors fwd a rev both with just 4 pins instead of 8 looks like you could use a transistor as a switch to bring the low side to vss
my bridge uses 9ma so the vdd needs to be a lite load not more then 5ma.

Post Edited (be80be) : 10/16/2008 11:49:35 PM GMT

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-10-16 23:08
    You'll need an H-Bridge for each motor. Many H-Bridges combine the transistor drive signals to provide a direction signal (forward / reverse) and an enable / disable signal with the option of using disable for dynamic braking. Do a web search for H-Bridges. There are some DIY versions that do what I've described.

    I don't know what you mean by lite load for vss. Vss is ground and is a reference point for logic and power supply.
  • John AbshierJohn Abshier Posts: 1,116
    edited 2008-10-16 23:13
    Micro Dual Serial Motor Controller, available from Parallax, used one or optionally 2 pins to control 2 motors. For bigger motors, the HB-25 only uses 1 pin. Some h-bridge chips (FAN8200 for one) only use 2 pins per motor. Many h-bridge chips use one enable input and 2 direction inputs, the two direction inputs can be combined with an inverter chip.

    John Abshier
  • be80bebe80be Posts: 56
    edited 2008-10-16 23:46
    I have a bridge it takes 8 pins 2 for fwd 2 for rev and the same for the second motor all i wanted to no is there a easy way to change it so that when its fwd is high
    i can bring its pin 2 low and just use 1 pin for fwd and 1 pin for rev on motor 1 and the same for motor 2. inverter could i not add a npn coming from vss that is also turned on by pin 1 to make pin 2
    low my motor are low ma 120 or so. sorry about the vss its vdd i have to switch vss was what i was thinking.

    Post Edited (be80be) : 10/16/2008 11:52:19 PM GMT
  • FranklinFranklin Posts: 4,747
    edited 2008-10-17 04:23
    That would depend on the bridge you have and if it can be converted to work the way you want. Add enough parts and anything is possible. Show us what you are using.

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    - Stephen
  • be80bebe80be Posts: 56
    edited 2008-10-17 15:58
    This is what i have I removed them from 2 toy cars and reused thy worked good with the car
    but thy need 4 pins each

    Post Edited (be80be) : 10/17/2008 4:03:47 PM GMT
    2pin.jpg
    803 x 555 - 26K
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