Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: lorddamax on October 04, 2010, 08:07:53 AM

Title: Reversing polarity?
Post by: lorddamax on October 04, 2010, 08:07:53 AM
For a halloween prop I'm building, I got my hands on a car door lock actuator... good fast, strong linear movement. Going to be used to make a prop jerk about.

Here's my issue... the actuator only has 2 leads. You reverse the in/out motion by reversing the polarity.

I'm trying to think of an efficient way to do it. They pull a lot of amps, so unfortunately it cant just be something simple.

Is there a device/method/system out there to reverse the polarity across two wires, then switch it back again at will?

The best I can come up with is a 3 SPDT relays... Relay1 sets Wire1 to Red, Relay2 sets Wire2 to black, and then Relay3 turns the thing on or off.

(I only suggest that because I already have SPDT relays)

Or I could buy a DPDT relay which would take care of 2 of the above, then use another SPDT to turn it on and off.

Is there an electronic solution to this without having to put 2-3 relays to use?

Thanks!
Title: Re: Reversing polarity?
Post by: rbtying on October 04, 2010, 08:15:10 AM
The DPDT would work, or an H-Bridge (you'd probably need to construct your own - 4 MOSFETS would do it)
Title: Re: Reversing polarity?
Post by: lorddamax on October 04, 2010, 09:00:25 AM
I have about 20 SPDT relays sitting here so I'll prob wire 2 up in parallel to simulate a DPDT relay, then use a 3rd to be the power switch. Was just wondering if there was an electronic way to swap the polarity without doing it with relays. No biggie. More soldering practice for me! ;)