HD44780 chip displays gibberish when motors started

I have built up a infrared sensor range finder car. It uses L298P to control two motors, i.e. a steering motor and a driving motor. The measured distance value is displayed on HD44780 1602 LCD chip. The car has a 5x1.5v battery power supply which is also connected to UNO VCC and GND.

The question is that HD44780 will occasionally display gibberish when the motors are started. I think it is because the motors made disturbance to the HD44780 chip. How to avoid it?

What information do you still need after your search for previous problems like yours?

Don

5 X 1.5 = 7.5 V and the Arduino Uno has a 5V Vcc........ ? Quite frankly I don't see how it could have worked at all, unless the batteries were dead ( a battery is usually considered used up @ .9V) so 5 X .9 = 4.5V good except it would go away when the device motor was powered up. should have displayed garbage text then...

Doc

I have a similer issue with motor start up . i am trying with two seperate power cords with class II power supply option , i will update