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Controlling a DC motor to only do one rotation and to be triggered using limit switch.

Hi,
I'm designing a mini golf hole for a festival in 3 weeks. The idea is to putt the ball in one hole and another ball to be released on another hole. I'm going to use a limit switch to as the trigger signal, but not sure how to get only one rotation on a dc motor and then to reset the trigger.

I have to run the whole circuit off 12v battery's.

Any and all help would be greatly appreciated.

Thanks!

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46
Jayefuu says: Aug 2, 2012. 9:31 AM
This can be done easily with a relay , a couple of limit switches and a 12V DC motor.

What is the motor doing? Lifting a ball out? Opening a gate?

What will happen to the first ball that goes down the hole? Will it carry on into a hopper or stay on the limit switch?
cmc graphics (author) in reply to JayefuuAug 2, 2012. 9:34 AM
the motor will be rotating a sort of feeder (circle of plastic with a hole just bigger than a golf ball cut into one edge), so would need it to either do a single rotation or a set degree rotation then to reverse back to home position.

The first ball will drop on a plate which will trigger the limit switch then fall into a hopper.

Thanks Jayefuu
46
Jayefuu in reply to cmc graphicsAug 2, 2012. 9:50 AM
Here you go.

You need a DPDT relay. A/2 is the relay coil. A1 is one of the relay contacts and A2 is the other one.

When the ball drops down the first hole LIM1 will close, turning on the relay. This in turn closes A2. The relay will stay energised even when the ball has gone from LIM1.

Since the relay turned on, A1 will have closed and so the motor will be turning.

The motor will remain on until the relay is turned off by a contact on the ball release gate pushes on limit switch two, opening limit switch 2 and turning off the relay.

Any questions?
46
Jayefuu in reply to JayefuuAug 2, 2012. 9:52 AM
Image didn't work last time. Let's try again.
SDC13397.JPG
46
Jayefuu in reply to JayefuuAug 2, 2012. 9:53 AM
Oh and if you want to read further about controlling with relays, Google "Relay Logic".
cmc graphics (author) in reply to JayefuuAug 2, 2012. 9:58 AM
Thats looks great, thanks a million . If lim2 is the home position and therefore will be closed in the home position, will this still work?
46
Jayefuu in reply to cmc graphicsAug 2, 2012. 10:05 AM
Lim2 should be open when at rest. But the tolerance of the mechanical bit that pushes on it should be close, if the ball in the hole rolls over LIM1 slowly there'll be plenty of time for the motor to turn a bit before the ball is off lim1. That make sense? It should just take some fiddling to get the mechanical bits right. I should have drawn Lim2 NO not NC.
cmc graphics (author) in reply to JayefuuAug 2, 2012. 10:15 AM
do you have any suggestion how to insure that Lim2 is open at rest, because i can't figure out how it is going to shut the circuit off and then be open without the feeder moving. I would guestimate that the ball would only be on Lim1 for .5 of a second, 1 second max.
13
steveastrouk in reply to cmc graphicsAug 3, 2012. 9:44 AM
Show us some pictures of the setup.
cmc graphics (author) says: Aug 2, 2012. 9:12 AM
i'm open to using any motor, its just the to get the single rotation and then reset is my problem.
9
kelseymh says: Aug 2, 2012. 9:09 AM
This sounds like a job for a servo motor.
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