# Switching polarity for linear actuators

I am working on a project for a client I have and need to figure out how to make this circuit work correctly. I have figured out WHAT I need, now I just need help figuring out HOW to make it work. I'm a novice with circuitry, so I don't know a lot of the terms and names of components, though I get the general concepts. Here's where it stands:

I have a Lutron motion sensor switch to sense when someone enters a room and will activate the circuit. What I need to happen is for some LED lights to come on as well as three linear actuators to activate. The catch is, when the sensor reads no activity for a programmed time (the Lutron sensor has the timer function built in) and opens the circuit, I need not only the lights to turn off but also to switch polarity, and supply power to, the actuators to get them to travel the other direction. I am a novice with circuitry, so I understand principles, but I can get lost in some of the lingo, so bear with me as I try to describe what I currently have.

I have the 120v line coming to the motion sensor switch, then splitting off to the 12v power supply/transformer for the LED lights and to the 12v power supply/transformer for the three actuators.Obviously, the lights are working fine with the simple "on/off" function of the sensor. The actuators have built-in stops on full extension/retraction conditions. What I need is a way to supply power to the actuators constantly, and when the Lutron sensor closes it's circuit, to switch polarity to the three actuators. Then, when the sensor re-opens, for polarity to switch back to idle state.

I tried to sketch this thing out and it looks like I'll need one "always on" 120v supply to the p/s for the three actuators and the 120v Lutron switch to the LEDs and to an H-bridge or other means of switching the polarity for the three 12v leads to the actuators. I think. Help, advice, suggestions?

DPDT relay?

If you know how to switch the LEDs on with arduino, and know what an H-bridge is, shouldn't be a big deal to figure out how to send 'run forward', 'run backwards', and 'stop' signals to the H-bridge.

What's the problem?

123Splat:
If you know how to switch the LEDs on with arduino, and know what an H-bridge is, shouldn't be a big deal to figure out how to send 'run forward', 'run backwards', and 'stop' signals to the H-bridge.

What's the problem?

Like I said, I'm a novice with circuitry. So, please "wow" me with explaining how "easy" it is to have power going to the actuators constantly, and switching the polarity using either an H-bridge or DPDT when the motion sensor switch is turned "on".

Thank you.

You might be able to use a DTDP relay like in the attached pix. When the relay is energized the actuator goes to extend limit, and retracts to retracted limit when deenergized.

If your linear actuator uses a brushed D.C. motor (most do) then use any suitable motor driver. “Suitable” means it must be able to handle the voltage and current required by the actuator.

I use Pololu motor drivers like this one for high power linear actuators. Follow their wiring directions carefully. These bidirectional drivers are capable of speed control, using the PWM input, but if you don’t need that, set PWM high.