Timer-relay setup for reversing DC motor polarity

Thread Starter

micakoenig

Joined Apr 11, 2024
2
Hello !
I'm an artist and VERY begginer with circuits and electronics. I'm trying to do a little machine in which a DC motor reductor unravels and then spins a yo-yo back up. Getting into ARDUINOs is a little bit to far for me, so I kind of want to do it with what I got, which are Timer-relays (at the moment I have 1 with three buttons and 1 with 4 buttons that accomodates for a trigger, I'll attach pictures below) and a DC motor. The idea is to have 1 timer connected +- to the motor, and the other one in the opposite polarity.
Every X amount of time
- timerA starts and the motor unravels the yoyo
- there's some waiting time to ensure there are not short circuits
- timerB starts rolling up the yoyo
- there's some waiting time to ensure there are not short circuits
and so on and so forth.

I'll show you my circuit idea where i think the times are too tight and will short circuit. How do I add that delay time? My new idea was to kind of use one timer as the trigger for the other BUT I don't think itll work because 1. Im not sure if the timer on-off signal counts as a switch, and 2. the signal on from timerA will trigger the on from timerB.
I was thinking of how to get a Resting state in which timerB is 'dormant for a 999 amount ', then every X amount of time, timerA turns on, then off, starts timerB in off which then turns on, and then dormant for 999 amount.
or every X amount of time, timerA turns on, then off, theres a delay for which timerB turns on and then off for 999 or until the cycle repeats.
That way they wont ever cross turns off for timerB. Maybe I'll need another timer or a relay but I'm clueless!

Thanks for reading, and sorry for the terrible graphics, its what works for me at the moment ! Ill get any help I can get !!

IMG_0070.JPGIMG_0070.JPG
 

MisterBill2

Joined Jan 23, 2018
19,052
The wiring diagram shows how you would connect but provides not even a hint as to how it would function. That is why I very seldom use them.
It seems that the goal is to unwind (lower) the object for some short time period and the wind it back up(raise) the object. Not at all like actual yoyo operation, but at a distance a simulation.
can these timers be programmed to repeat cycles? Or do they need to be triggered to do one cycle and then wait until the next trigger?
If this is to be a constant cycling then each timer needs to trigger the other one when it has completed it's time period.
There is a simple scheme to have one run the motor to lower and the other run the motor to raise, and it is nothing at all like the one shown in the wiring diagram. Both timers would need to be triggered, but we have no hint as to how the timer is triggered.
So more information would be useful.
 

LowQCab

Joined Nov 6, 2012
4,218
Can the weight of the Yo-Yo cause the Motor to spin in reverse ?,
If so, there is no need to actually provide "power" to the Motor in reverse rotation.
If the Motor spins too fast from the weight of the Yo-Yo,
the Motor can be used as a generator to provide any degree of free "braking-action"
needed to achieve the desired "un-winding" speed.

One Timer should be all that is needed in any case.
Possibly even no timer at all,
which would also tend to extend the life-expectancy of the Motor.

A "rotating-crank" arrangement pulling the string,
with the Motor running continuously at a steady pre-set-speed,
would be the best set-up, if there is physical room for it in, or somewhere near, the model.
.
.
.
 

Thread Starter

micakoenig

Joined Apr 11, 2024
2
The wiring diagram shows how you would connect but provides not even a hint as to how it would function. That is why I very seldom use them.
It seems that the goal is to unwind (lower) the object for some short time period and the wind it back up(raise) the object. Not at all like actual yoyo operation, but at a distance a simulation.
can these timers be programmed to repeat cycles? Or do they need to be triggered to do one cycle and then wait until the next trigger?
If this is to be a constant cycling then each timer needs to trigger the other one when it has completed it's time period.
There is a simple scheme to have one run the motor to lower and the other run the motor to raise, and it is nothing at all like the one shown in the wiring diagram. Both timers would need to be triggered, but we have no hint as to how the timer is triggered.
So more information would be useful.
Hi ! Thanks for your answer and sorry for the diagram, I'll try to explain better. Yes, what im trying to do is as you said to unwind (lower) the object for some short time period and the wind it back up(raise) the object. The timers can be programmed to repeat a cycle indeed, which is what I'm doing. The way its currently working is the following
- There's an on-off switch attached to the power supply and then to both timers, so when I turn the switch on both timers turn on. The first timer starts OFF and the second one ON. TimerA is connected to the motor +-, and timerB -+. So when timerA is on, the motor rotates to the left, and when timerB is on, to the right. They both start their cycles immediately when turned on through the switch.

What you said here: "each timer needs to trigger the other one when it has completed it's time period." Thats what I want to do but I'm not sure of how to do that. Today I'll be trying some stuff out, hopefully I get it right.

Thanks
 

MisterBill2

Joined Jan 23, 2018
19,052
Alternate triggering of the timers will be the very hard part.
The scheme for alternately driving the motor in opposite directions is cheap and easy, a variation of the two relay scheme I have presented many times.
The motor drive supply is tied directly to the relay contacts, usually the positive ties to both normally open contacts, the supply negative ties to both normally closed contacts, and the motor connections tie, one to each relay common terminal.
Operating one relay spins the motor one way, operating the other relay spins it the opposite direction. Operating both relays at the same time does nothing at all, except apply a bit of braking torque by shorting the motor connections.
Caution because with both relays released the motor is also short circuited. So the circuit is not symetrical like some reversing schemes. But it works very well.
Unfortunately I have no information as to how to trigger the two timers alternately.
 
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