Micro serial servo ctrl + Low Volt dual serial motor ctrl PB

Hi everybody

First, i manage to control both of the Micro serial servo and motor controller separatly.
My problem is that i can’t manage to put the same line of power for my servos and my motors. if i do so, my servos are not responding while my motors run. when my motors stop the servos are responding again.

Here is the connection of the line of power:

On the Micro serial servo controller the vcc = vs jumper is off. The line of power is connected on the servo power (4-6 V) line + and - . i put a 1µf capacitor between the + and -.

On the Micro serial motor controller the line of power is connected on pin 1 and 2 respectivly motor sypply and ground (the ground is also connected with the µctrl ground). I also put a 1µf capacitor between the + and -.
Two motors are connected.

On the other hand both cards are connected on a 5V 890mA DC power supply.

When i put separate power supply on the cards everything is working just perfectly.

Any idea on the nature of this problem?



Hello, Gwenhaël.

It sounds like you are having a power supply problem. A single 890mA power supply probably cannot supply enough current to run motors and servos at the same time. You should figure out how much current your motors will draw. As for the servos, a good rule of thumb is that you should have 1 A per servo. Then you can get a power supply that provides enough current for everything, or you can continue using multiple power supplies if that works for you.


Thanks for the clue David. I will test this way and see if it works.


Ok so it a bit better. I test it with 5 AA battery but my servo are not very stable (they make some little moves while i command them not to). The problem is that i already have a capacitor on both cards power supply.
is there something i can do to limit the noise on my servo controller?

Sorry, it’s hard to tell what might be going wrong now. Are the batteries NiMH or alkaline? Maybe if you simplified your system to the simplest possible thing that causes the problem, you could figure out what is causing the servos to make little movements.