Robot Cart - Shovel & Pile driver

This is the latest version of the Robot Cart using the BBC micro:Bit. Essentially a remote control car.

Most of the development was due to my 5 year old grandson’s comments when he was playing with various versions of the Cart. When it had just the shovel on the front he said, “…it would be really good if it had a digger on the back to SMASH through concrete and rocks …”. He really likes industrial machinery.

My skills and equipment are beyond the ability to build a backhoe, but I came up with an idea for a pile driver mechanism. The grandson is yet to see this due to Covid lockdown. The mechanical design was a real challenge for me. I destroyed two servos in the process, one to over voltage, the other mechanical when I drove the cart of the desk. The pile driver lift mechanism is quite fragile.

The activation of the solenoid stresses the batteries, so I added a separate supply, but even with that you can see it affecting the shovel servo which is powered from the main battery pack. The solenoid draws about 1A when activated.

The arcade style joystick and buttons are almost unbreakable. When the cart had just the shovel, the 5 year old was quite violent with the joystick and buttons but they survived intact. The range is limited due to the micro:Bit being inside the box. Also the software in the cart has been changed to check for communications with the controller and shutdown if there is none. Previously the cart would just keep going if it lost comms. I used Micro Python to program the cart and controller; highly recommend this for anyone with some programming experience. It was very easy to use and debug.


PS I put these projects here as an example of what can be done with the BBC micro:Bit, it is an awesome device, with so many features. Ideal to use as a teaching tool.

My Movie 01 (1)


Hi James,

It’s amazing to see your project evolve! You’ve got quite the “client” on your hands with your son and his requirements for durability and performance :smiley:

Keen to see your next instalment! Looks like you’ll be competing on BattleBots soon enough :laughing: