I need some electronic circuit help...

[basslover911]

I am building a light mover for my fish tank (moves light from side to side).

Basically, I need a circuit with two limit switches at the end of the fish tank to reverse the motor direction when it gets to the end of the track (and so that it starts going the other way, in an endless cycle);

I know I need-
2 limit switches
dc motor
dpdt relay
timer relay (to stop at the ends for x-amount of time).
pot (to adjust dc motor speed aka how fast the light moves from side to side)

Can anyone make an "idiot" proof diagram for me? I understand I need some sort of "latching relay" thing...




This is a diagram someone posted on my fish forums but I can't understand it at all...

[bestclimb]

Or a stepper motor with a controller that only lets it go so many steps in one direction then the other.

[Arragonis]

Why not make it simpler. Make a mechanism like a ski-lift - two wheels with a loop of wire or string between them. If you rotate one wheel the string will move between them. Then suspend the light from a cord attached to the string. When it reaches one end it will turn and then go back again.

Something like this :



The only thing you would need is a rotating mounting thing for the light so that if it has a cord, the cord doesn't twist.

[basslover911]

Originally Posted by Arragonis

Why not make it simpler. Make a mechanism like a ski-lift - two wheels with a loop of wire or string between them. If you rotate one wheel the string will move between them. Then suspend the light from a cord attached to the string. When it reaches one end it will turn and then go back again.

Something like this :



The only thing you would need is a rotating mounting thing for the light so that if it has a cord, the cord doesn't twist.

I can't do that because;
1) the electrical wire would get tangled
3) the light is wide and can't "turn" as it would hit the top canopy.

Basically, how could I copy a light mover? they use DC motors and limit switches... I just want to copy the circuit diagram (since they are so expensive to buy lol)...

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[Odin]

^^^ what happened to step two?

[dcb]

the circuit thing is very doable on the cheap but hard to explain, so I'm going to offer another largely mechanical solution (aka crankshaft)

This needs some clearance, but you get the idea, might be able to put the motor ON the light and regain some clearance on the right. Need a solid rod connecting the arm to the light here. Might also adapt a scissors/extender thingy somehow and not need additional side clearance.