Arduino + h bridge l298n + dc motors, robot move a litle and then gets crazy

Other Hardware Motors, Mechanics, Power and CNC
1

Hello friends, newbie here! sorry about mi english.

I have a tipical configuration, Arduino + h bridge l298n + 2 dc motors

this is mi h bridge: http://www.haoyuelectronics.com/Attachment/L298N_module/1.jpg

pins 2,3,4,5 goto h bridge, 4 AA bateries alimentate the h bridge, and i put common ground betwen arduino and h bridge.

I controll all this, from serial monitor from arduino ide

MY PROBLEM: Robot works fine 3 seconds, and then serial communication gets lose, and motors move and move, and i have to restart arduino board to make them stop. This happends in every direction.

Thanks for your help

2

Could be interference from the motor circuitry being picked up by the Arduino, even
with separate supplies.

First with the L298 I believe you have to keep the motor voltage at least 5V or
else the Arduino power will be used to help drive the motor - in other words the L298 and
similar drivers have a diode between motor and logic supplies as part of their
construction. Normally the motor supply would be a lot more than 5V and this wouldn't
show up, but with 4 AA's for the motor supply its close to the limit.

3

Thanks MarkT, this you told gives me some clues to start debuggin, i forgot to say i alimentate arduino and h bridge separated

4

Also realize that the L298 drops a couple of volts from the supply - so your 4.8 - 6 volt supply (not sure what kind of batteries you are using) could be as low as 2.8 - 4 volts by the time it gets to the motors...