Issue with HG7881 motor driver and HC-SR04 sensor

If i use the HG7881 and power up a motor, the readings of the HC-SR04 are totally wrong. I have read in another post that probably the h-bridge is poorly isolated and that i need a second power source to supply the sensor and motor driver separately.

Is there another way to isolate the h-bridge without adding a second power source?


Here is a picture of my setup. The notes represent the connections to the HG7881. The parts work on their own but i cant get them to work together with a single power source.

Any ideas?