General Help with obstacle avoiding car

I have general questions and need some guidance.

I have Arduino Uno, a Seeed Motor controller V2, and a Ping sensor.

My coding skills are pretty good/ok

Ok, so I found an old RC car at the thrift store and wanted to make it into a collision avoiding car.

So I connected the Ping sensor and was able to get distance.

Next I was able to get the back wheels to go forward, stop, then go backward successfully when the ping sensor senses an object at a certain distance.

I was also able to get the front wheels to go left and right.

I have a problem when I connect both DC motors at the same time. The front wheels stop moving. The back wheels move slowly or don't move at all.

So I know the code works, the motors just grind to a halt when connected together. I am good at code but new to hardware. Is this a voltage problem? I connected the arduino through the wall plug. Are the motors too big? Should I find a smaller car or is there a way to boost the voltage to the motors?


the problem is that you need to always separate the power to Arduino and to the motor, same goes to servos too. hope that helps