4WD robot rebuild

Few months ago my path crossed with this 4WD robot from Keyestudio ( there are literally tons of clones available on internet)
I am not satisfied with look of this funny thing an there is also some features missing so I decided to give him a little ( rather big) rebuild. So this is work in progress.

TLDR:

1. Rear bumper / cover - done.
2. Holder for 10000mAh powerbank - done.

Next step : Front bumper with integrated ultrasonic sensors. - in progress

Last step: power motors directly with step-up converter/booster for better performance.
Last last :-) step: wireless charging with auto-homing.

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Step 1 rear bumper: there is no need for explanation - pretty simple design and printing.

Step 2 powerbank bracket: it is not some beautiful piece but for prototyping sufficient. For simplicity reason and convenient charging I decided to use some common noname powerbank that is used to charging 5V appliances. There was some hick-ups on the way so be carefull. Motor driver used in this particular robot (L298N) is not, what you call, efficient so there is big voltage drop-out on output. With 5V power you can expect 3.3V on motor. So one of future todos - powering motor through step-up converter may be up to (9V used motors should take 6V input)