Easy 12v time relay help!

[mlawler0]

Hi all,

I am sure for most of you this would be a very simple project but I am very new. I want to run a very small 12 volt motor off a deep cell battery. I need the motor to turn on for 3-5 seconds (can this be adjustable) then turn off for approx 8 seconds.

The motor will be winding in a rope until the rope is completely in then releasing the rope back out, then pulling it back in, etc.

Thanks for your help in advance.

Mike

 

[MikeMl]

What condition makes the motor reverse? Are you counting turns of the capstan, or sensing the capstan being full of rope with a microswitch?

 

[mlawler0]

The other end of the rope has bungee that stretches as the motor winds it in.....when the motor stops the bungee pulls the rope back out.

 

[MikeMl]

You explained what you are doing to keep the rope taut on the capstan; I guess you are banking that the bungee can "free-wheel" the motor when power is removed?

 

[mlawler0]

You explained what you are doing to keep the rope taut on the capstan; not what decides how long the motor runs so that it always returns to a known starting point. You cannot do this by time alone; you need an indexing/limit switch somewhere in the system.

I guess its more difficult than i thought, there is a big ring that doesn't allow the rope to be drawn in any further but i am guessign if the motor continued to try to pull that would not be good.

 

[MikeMl]

I guess its more difficult than i thought, there is a big ring that doesn't allow the rope to be drawn in any further but i am guessign if the motor continued to try to pull that would not be good.

Reread my previous post again, I edited it while you where replying. After rereading the original post, I think you can do it without the limit switch, since the motor is whimpy...

 

[mlawler0]

Yes I am banking that the bungee will free wheel the rope back out....what do you think?

 

[MikeMl]

This should do what you want. You will have to determine the polarity of the motor leads. I'm assuming the motor draws less than 1/4A.