As you can see from the build image, the power bank is attached on top of the zumo chassis using  double sided tape. On top of the power bank attach a piece of rectangular aluminium section cut to the width of the chassis to hold the pi and the pi camera in place. Pi and the pi camera is also attached in place using double sided tape.

Find files for 3D printing the robot body here -> https://www.thingiverse.com/thing:6025164

We are using GPIO23, GPIO24, GPIO22, GPIO27 and ground pins  for motor control.