Circuit to switch off a DC motor

[Chami]

Hi, I am looking for a circuit to be used in building a model railway level crossing. The motor should stop after couple of seconds once the gate is opened. Then reverse the motor and stop it again after couple of seconds once the gate is closed. Can you please help me with a circuit for this?

 

[AnalogKid]

Your question has very little information.
Are you talking about the motor in the train, or the motor that operates the gate?
Are there a sensors on the gate to indicate when it is fully open and fully closed?
What voltage?
What current?
What tells the gate when to open?

ak

 

[Chami]

Hi ak,
This is for the motor that operates the gate. The motor I have is 6V 10RPM geared motor. There are no sensors. There is a DPDT switch to trigger opening and closing of the gate. I want the gate to move from the "Closed" position to 90 degrees and stop and vise versa.

 

[Alec_t]

You could start by fitting limit switches to the gate. Why do you want to wait a couple of seconds before turning the motor off? Wouldn't it be better to turn it off as soon as the gate reaches one of its limit positions?

 

[AnalogKid]

Hitting 90 degrees with nothing but a timer means it will have to have an adjustment so it can be tuned.

There is a DPDT switch to trigger opening and closing of the gate.

Is this the sequence:

Everything off

Switch closes > timer starts > motor runs > gate opens > timer stops > motor stops > gate is held in open position

Wait

Switch opens > timer starts > motor runs > gate closes > timer stops > motor stops > gate is held in closed position

Repeat

?

ak

 

[Chami]

Hi Alec_t, I tried limit switches and finding it difficult to position the motor. I don't have a motor housing to keep it steady. I tried making one my self. It works some times, when operated for few times the motor position changes slightly and the motor does not stop in the horizontal position. These are practical difficulties. That is why I thought of looking for some sort of a circuit to stop the motor.
I uploaded a photo.

 

[Chami]

Hitting 90 degrees with nothing but a timer means it will have to have an adjustment so it can be tuned.

Is this the sequence:

Everything off

Switch closes > timer starts > motor runs > gate opens > timer stops > motor stops > gate is held in open position

Wait

Switch opens > timer starts > motor runs > gate closes > timer stops > motor stops > gate is held in closed position

Repeat

?

ak

Yes, this is the sequence.

 

[Bluejets]

Use an rc servo, made for things like this.