Not getting constant speed


I’m connecting two low-voltage dual serial motor controller to two tamiya’s twin geared dc motors. these two controllers sharing one 5V supply and the motors are sharing another 5V supply. These two motor controllers are sharing one serial input line. My Problem is that after turning the motor controllers ON and sending a command with a fix speed to these two controllers, the speed of the four motors goes up and down !!
Any thoughts ??
Thanks inadvance for any help.


Barmak :sunglasses:


The problem is probably with your power supply. What are you using for the motors? Do you have a way of monitoring the motor supply (e.g. an oscilloscope)?

- Jan


I were using a 4.8V power supply for both. I changed it into two 2.4V power supplies and now the DC motors are working properly.
Thanks for your help.