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I'm trying to accomplish this. When a dusk dawn switch is on, drive a small DC motor for a few seconds and then stop. when the dusk dawn switch is turned back off, then turn a small DC motor THE OPPOSITE WAY for a few seconds and then stop.

Or to say it another way: Input circuit closed, then close motor circuit for variable time (1-60 secs) with default polarity +-, after variable time expires then open motor circuit.

Input circuit open, then close motor circuit for variable time (1-60 secs) with reversed polarity -+, after variable time expires then open motor circuit.

I can handle the input circuit, but the timer and reversing polarity are stumping me. anticipating DC motor in 12V range <5A

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  • \$\begingroup\$ Have a search for "H-bridge" - that'll get you started... \$\endgroup\$ – awjlogan Dec 4 '18 at 16:44
  • \$\begingroup\$ The dual-half bridge or dual SPDT relay is only part of the solution, the other part is determining when to stop by position sensing or current limiting or fixed time interval that must be defined. Then a State Diagram to define the fail safe logic and driver. Lots of solutions already exist for a chicken coup door. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Dec 4 '18 at 16:54
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I assume you're opening and closing some blinds or shutters or something like that. It's actually much easier to use limit switches rather than timers.

The "master switch" is a DPDT switch that controls the direction of the motor. When you flip it, the motor runs in that direction until the corresponding limit switch opens. If you really want the master switch to be SPST, then you use that switch to control a DPDT relay.

schematic

simulate this circuit – Schematic created using CircuitLab

You need to select diodes that can handle the motor current. The 1N400x series is only good up to about 1 A.

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