Two-way 12V motor control using arduino and darlington?

[Empty_Atoms]

Howdy,

I'm currently trying to build a door mechanism with an arduino, I have a circuit built from this article which enables me to control the current to a 12 volt motor using the arduino to open a path to ground.

My question is this, how do I get two-way control out of this circuit? I get the sense I'm missing something very simple here but if I want to use a second pin of the arduino to send the opposite current through the motor, what's the most efficient way?

 

[Bluejets]

Just use a H-bridge.
Designed for the job.

Example youtube video........

 

[Empty_Atoms]

Thanks a mil, great info!

I suppose the idea of buying an actual motor driver is making more sense by the minute.

Is there no way that I can open an opposite flow of current through the motor using a second signal pin and a second transistor? I've ordered a few H-bridges but it really feels like something that should be possible with what I already have.

 

[BobK]

Well, you can make an H bridge from 4 transistors. You need 2 NPN and 2 PNP or 2 N-channel and 2 P-channel.

Bob

 

[Empty_Atoms]

I figured I'd need at least 1 PNP. That's a massive help bob thanks so much for your time.

 

[BobK]

If you do go the way of a discrete H-bridge, be aware that you will also need a level translator for each of the high-side switches (PNPs). The complete circuit will require 6 transistors.

Bob

 

[Bluejets]

You could also use transistors and a couple of changeover relays.