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DC motor control

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Hello All!

Does anyone have any ideas on how to make DC 12V motor controler that will turn the motor on and of with the single click of the switch? First time you click it is on. the second time you click it is off. Or even better if you click first time it is running in one direction and if you click second time it will run in the opposite direction.

I am trying to have the motor move something to the certain point and then stop when it reaches the point with the single click. then after it stoped , by pressing the same switch again to come back to the original position. THe circuit will actualy need to control the polarity of the motor so it can go back and forth. also, the circuit would need to stop and reset it self when the motor moves the object to a certain point. it would be a contact touching another contact (like a limit switch).

any ideas are greatly apreciated.
All you need is a flip flop which will set and reset alternately on press of a button. See attached schematic.


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this is great

would pressing the switch reverse the rotation of the motor or it will just turn it off?

is there a posibility to add the limit switches to this circuit so it will stop the motor after the moving object reaches the certain point?

Thank you. George
The circuit will only turn the motor on and off. For reversing the direction, use H-bridge along with this circuit.

Yes there is a possiblity to stop the motor when desired. Use the reset pin for this purpose. In the circuit it is connected to output Q2. Remove this connection and connect this pin to your sensor which has active high output.
H bridge

do you have the H bridge hady? can you post that too?

Now will the same switch do the reversing when H bridge is added? Do you know if the limit switch will work if I connect it to RESET pin?

Thanks, George

After i reset the flipflop, if i click on the switch, will it work again or i should do something else?

What i actualy want is to click once and have the motor to spin in one direction to move the object till it hits the limit switch(reset)
then, to click the second time the same switch and have the motor to spin the other way to put the object to its original position stoping again by trigering the second limit swich (reset)

now H bridge has 2 trigers. How can i combine H brigde and flip flop to do this with only one switch?

Thank you for your help so far. George
OK here is the schematic of what you want.

There was a small mistake in the previous schematic which has been corrected now. The clock is positive edge triggered so you need to interchange positions of R and SW in the old schematic. New one is ok.


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reset switch

It looks great but I am confused by reset switch circutry. Am I supposed to triger them with +12V or with the ground?

If with + then when the object is in its position, pin 14 will have positive charge and clicking on switch SW would have no efect. correct? can I connect reset switch circuit to pin 15 then as that is the reset?

thanks, George
The reset circuit should be designed such that it gives a momentary +12V pulse to the circuit. The solution is to remove those two diodes and replace them by 0.1uF capacitor.

That is great. Should i keep all the same and just replace diodes with capcitors or should I connect it to reset pin?

How hard is it to have some kind of overloading circuit build so if the motor gets stuck it stops and goes in the oposite direction?

Well, you don't have to connect it to the reset pin.

The overload protection will need lot of changes in the current design.

I am sorry for bugging you, but your knowledge just seams to be solving all of my problems that i have in this project.

can you please post the whole diagram with the limit switches and the overloading circuit?

so this circuit will start the motor in one direction by pressing the switch for the first time, stop at the point a(limit switch) and then move in the other direction by pressing the sw again. finaly it will stop at the point b (second limit switch). now just to figure out the overloading and reversing.

thank you for your help so far. George
What do You think about my circuit?I've designed few years ago for car-aerial motor.


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re sebi

Sebi, what do you think about our little discusion on this subject? did you have a project like this before or similar? any ideas?

Thank you, George
O.K. pm me. Yes, as i wrote i've built this for my car-antenne motor. Bidirectional and automatic stop by current sensing.
Even this is a good idea. It incorporates overload protection. But it does not have single switch. Here you'll have to use 2 switches but that is not a big problem I think.

You have not mentioned the capacitor valuesi in the schematic, Sebi.
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