HI,
Im new to this forum,
sorry for bad language hope you can get it anyway

I would like to hear if you have any ideas on how I can control a motor using relays. Automotive relays?
The function i looking after is:
I have a platform that goes on a rail, in each side i have a limit,
in one side i have mounted a 12v dc motor and a Wheel, and in the opposite side a Wheel, i have stretched a wire between those Wheels
who is attached to the platform,
i have ha momentary startbutton.
the limits have COM,NO,NC
i got a 12v timer.

If i press the start button i want the platform to start and when it hits the limit in the end it will stop and start a timer who goes for 3-4 seconds and then return, when the platform hits the other limit i want it to stop, until you press the start button again, then let it do the same again

I attached a Quick drawing if it will help.

Thanks for ideas/Micke

 

Your question is very clear. Where are you located? What is your electronics background? Do you want to use a microcontroller like a PIC or Arduino, or do you want to use discrete chips like logic gates? This can be done with two 4093 NAND gate devices and two transistors to drive the relays. You will need two SPDT relays that can handle the motor current.

ak

 

It should be possible easily without electronics with an off the shelf timer and hard wired relay logic.
Max.

 

Your question is very clear. Where are you located? What is your electronics background? Do you want to use a microcontroller like a PIC or Arduino, or do you want to use discrete chips like logic gates? This can be done with two 4093 NAND gate devices and two transistors to drive the relays. You will need two SPDT relays that can handle the motor current.

ak

thanks for quick answers
I'm located in sweden,
has only a little experience in electronics. I can solder together a circuit board if anyone can say what components I should have and draw up a drawing of the circuit.
My idea was to keep it as simple as possible, i have wired upp two spdt relays as a polarity switch just to run the motor when i test-drove it.
i forget to mention that i would like to have a potentiometer to control the speed of the motor if its possible


but it is more basic to use electronics or do as Maxheadroom suggest whit hard wired relays?

 

If I remember Max's past posts correctly, he has a lot of experience in industrial controls. For the one's I've done, I tend to keep my logic in logic chips. Attached is a first-pass at a track controller.

Note: U2 pin3 is floating on purpose.

ak

 

i forget to mention that i would like to have a potentiometer to control the speed of the motor if its possible
but it is more basic to use electronics or do as Maxheadroom suggest whit hard wired relays?

I was thinking of keeping it simple, without the need to construct any custom S.S. logic etc.
A potentiometer alone is not an ideal way to control a DC motor.
Depending on what the motor current is, there are PWM controllers on ebay for $5.00.
You would need a timer, two (Fwd/Rev) relays, two limit switches and the speed control.
A couple of P.B.'s.
I can put a circuit together if needed.
Max.

 

If I remember Max's past posts correctly, he has a lot of experience in industrial controls. For the one's I've done, I tend to keep my logic in logic chips. Attached is a first-pass at a track controller.

Note: U2 pin3 is floating on purpose.

ak

Okej, the file you attached dosent work for me ?

Thanks/micke

 

I was thinking of keeping it simple, without the need to construct any custom S.S. logic etc.
A potentiometer alone is not an ideal way to control a DC motor.
Depending on what the motor current is, there are PWM controllers on ebay for $5.00.
You would need a timer, two (Fwd/Rev) relays, two limit switches and the speed control.
A couple of P.B.'s.
I can put a circuit together if needed.
Max.

Okej, yes if you can put a circuit together it would be nice
What is P.B,s ?
I can try to get the data sheet of the motor

Thanks /micke

 

This is what i found on the motor.
Its from a sqrewdriver.

 

P.B.'s = Push buttons.
Have you actually confirmed that motor will drive you desired load?
Max.

 

P.B.'s = Push buttons.
Have you actually confirmed that motor will drive you desired load?
Max.

Ahh okej

Yes, when i tested the track by drive the motor manual it seems to work , i was thinking that a sqrewdriver was build for hard work, do you have any suggest of another motor ?
I have tought about a motor from a car that runs the windscreen whipers?

/micke

 

If you intend running off battery power, you need to use the most economical motor you can.
The largest source of 12vdc motors is autowrecker yards etc.
Max.

 

If you intend running off battery power, you need to use the most economical motor you can.
The largest source of 12vdc motors is autowrecker yards etc.
Max.

Okej but if you have time and want to you can draw up the circuit

 

Okej but if you have time and want to you can draw up the circuit

I just have to finish a project and will do it after.
Max.

 

Here is a circuit that should serve your purpose. Now I would use a microcontroller.

Ken

 

Here is a circuit that should serve your purpose. Now I would use a microcontroller.

Ken
View attachment 86108

Okej thanks for the drawing.

Okej, the file you attached dosent work for me ?

Thanks/micke

the file work, it was my phone that dosent work, is it possible to change the time that the platform stand still in the end position? and if its possible to controll the speed. ?

 

It is designed to have an adjustable pause time. If you want to control the speed you will need a PWM speed controller added.

Ken

 

It is designed to have an adjustable pause time. If you want to control the speed you will need a PWM speed controller added.

Ken

okej is it much work to draw in a pwm controller for you ?

/Micke

 

I don't know what the maximum motor current or your minimum and maximum speed will be, so can't really design it.

Ken

 

I did something very similar about 6 years ago. The differences are: mine has a cable strung 6 ' in the air between 2 poles about 80' apart.
The target is attached to a 1/4" wire frame hanging off the cable. It is controlled with a 4 channel wireless remote ( so range officer can move with officer and not get tangled up). It has 2 speeds, speed can be changed at any time during travel. And it have a siren connected to it so range officer can replicate an actual chase with all the noise/confusion. [