Let's Make Robots!

Powering the Dagu 4 Channel Motor Controller

Hi All,

I'm all set to start on my first robot as described in an earlier topic - Rover 5, Dagu Redback and Dagu 4 ch motor controller. I tend to take instructions a bit literally sometimes but the manual for the motor controller says: "The motor power supply should not be connected without first connecting the +5V for logic". My intention is to power the whole setup with a 2S LiPo (probably a 2650mAh). In which case, can the motor supply and +5V logic (which I'll source from the Redback 5V output) be connected simultaneously or do they really need to be connected in sequence?

Thanks,

Paul.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Thanks again to both of you for your suggestions. I bought a couple of LM2940CTs this morning so I'll make up a regulator or two and feed the logic supply from it.

It is best if the 5V logic is powered by a regulator that gets it's power from the motor power. In future version of the PCB I plan to include a small 5V regulator to solve this problem.

If you leave the Spider power switch in the On position and then use 1 master power switch for everything then that will be fine. Make sure your power switch is rated for at least 4amps. An automotive switch is a good choice. You can get them with ratings up to 30A!

I happen to have the same setup, Dagu Rover 5 / red back spider / 4ch motor controller. When I first started playing with it I used the 5V of the red back spider to power the logic of the motor controller. It works but the red back spider controller has an on/off switch, when you put it in the off position the motor controller logic will not get 5V anymore while I would still have power connected to the motor controller (Vbat). So it's  not very practical. So I came up with a simple solution. I made a small PCB with some terminals on it. From those terminals I distribute the Lipo battery power to the motor controller, red back spider and an UBEC (for my gripper).  The PCB also has a 7805 vreg, this vreg powers the logic of the motor controller. That way I always have 5V at the logic of the motor controller when I connect the battery.

This is my Rover 5: http://letsmakerobots.com/node/31410