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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?



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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