The quest continues to find a LEGO set that can be easily converted to remote control. In a moment of tidying up, I re-discovered this bulldozer (Dozer set 7685) in the corner of my study. A prime candidate to try adding motors and an SBrick.

This bulldozer set is not supplied with motors, and has no instructiors for adding them. But there is lots of space internally. I rebuilt it a few times, added two M-motors, a few gears, a battery box and the SBrick. Staying true to the original model was quite a challenge. The tracks are now half a stud further out than in the original model, and the plough-arms at the sides only just miss the tracks.

The remote control equipment in the Power Functions range uses infra-red, and therefore isn’t technically “radio” control. It offers limited control – basically forwards and backwards at full speed. The SBrick permits finer motor speed control, uses Bluetooth instead of infra-red, and is controlled from a smartphone. Up to four motors can be controlled at once, though only two are used for this model.

More details of the drive mechanism, the build, the SBrick interface and the challenges in building this model will follow in future posts. Please let me know what you are interested in (in the comments below) and I’ll do my best to answer.