I need electric help! --- How to reverse polarity?

[basslover911]

I have a 2-wire door lock actuator and a float switch.

When the float switch turns on I need the actuator to move one way. When the float switch turns off I need the actuator to move the OTHER way. So I need a way to reverse the polarity of the actuator through a relay somehow. Anyone know how?

Actuator has 2 wires (+ and -)
Float Switch has 2 wires (+ and -)

I need a relay or something in between??

[Bicycle Bob]

Maybe you want a double pole double throw (DPDT) float switch.

[Daox]

When I was making my actuated grill block for the Matrix, I was doing something similar. I needed to be able to reverse the door lock actuator I was using. I got the advice from dcb to use an h-bridge to control it. You should be able to use one for your setup.

If you aren't using any controller (I used an arduino) you'll need to add limit switches to the setup though. Door lock actuators are dumb. You give them power and they keep trying to go in our out until you disconnect the power. If you leave the power on them too long I'm sure they'd burn up. You'll have to add switches and relays to each end, so when it reaches the end of the throw it disconnects power.

[JasonG]

The best and easiest fix is as follows:
Get a on-off-on DPDT momentary switch (door lock switch from junk yard should be near free)
Wire the actuator red to common 1 and blk to com2.
Wire 12V red to NC1 and NO2
Wire 12V blk to NO1 and NC2

[wagonman76]

Originally Posted by JasonG

The best and easiest fix is as follows:
Get a on-off-on DPDT momentary switch (door lock switch from junk yard should be near free)
Wire the actuator red to common 1 and blk to com2.
Wire 12V red to NC1 and NO2
Wire 12V blk to NO1 and NC2

Here is a diagram of what Jason means.

[basslover911]

Well the thing is I need this to be automated. This is what needs to happen;

Bucket fills with water


Float switch pops up


Actuator moves plunger

Water Drains

Actuator goes back down so water can fill again


And repeat... all by itself.

Would this diagram work?

[Bicycle Bob]

Why not use a toilet tank flapper and a float on a string?

[basslover911]

Well because that makes too much noise when the water reaches below the flapper and releases tons of bubbles ... Both things that I can't have

which actually... If you could make a toilet flapper close before the water gets to the bottom then I guess that would work too but how would you do that?

[Bicycle Bob]

With a second float that is on a short string and drops a weight onto the valve. You probably also need a device to keep the main float from slowly lifting the valve. It should get almost submerged before a magnet or something lets go, and lets it jerk the valve open all the way.

P.S. This sort of action can also be accomplised by balancing a trough near the middle and filling it with water until it tips, lifting a weight on the short end, which is probably easier. I've got some ancient examples, but they are in books. I presume you can find stuff like that on-line.