Sariel.pl

An advanced diwheel using BlueSmartControl unit to act as a camera dolly. Features two motors with independent speed control.

Datasheet:

Completion date: 09/08/2015
Power: electric (Power Functions)
Dimensions: length 26 studs / width 30 studs / height 25 studs
Weight: 0.689 kg
Suspension: none
Propulsion: 2 x RC motor
Motors: 2 x RC motor

This creation was successor of my first diwheel built 6 years earlier. Diwheels are essentially bikes with wheels around them. Unlike the earlier version which was fitted with a subtractor and could only turn at one constant angle, this was equipped with BlueSmartControl prototype unit, enabling accurate speed control of both motors.

The vehicle was based around two super-rare LEGO wheels from the old 4481 set, with one RC motor installed on each wheel. The wheels were inclined away from the center, with their tops being set apart. Such an arrangement prevented them from obstructing camera’s view and I was also hoping that it would lower the risk of the whole vehicle gerbiling. My thinking was that when inclined wheels roll over, they tend to roll away from each other. Thus, they should have a natural tendency to return to the point at which they are closest to each other, which is the vehicle’s bottom. I can’t honestly say if this worked, but the vehicle proved reasonably stable and, of course, rolled over every once in a while. To keep the inclined wheels stable, I have put clamps on their opposite sides: tops and bottoms, with RC motors acting as rigid connectors in between.

The center of the vehicle was housing a single 8878 PF battery, the BSC unit and a GoPro 3 camera. All of these have been arranged to lower the vehicle’s center of gravity, with the battery in the middle. I decided to try running two RC motors off a single battery, something that’s not recommended, because I was planning to use the vehicle mainly on smooth tarmac, thus avoiding stressing the motors. This proved problematic anyway: the battery would shut down every once in a while, the BSC unit had a tendency to get hot, and driving into rough terrain such as grass would make the battery shut immediately.

For a while I was playing with idea of using my GoPro gimbal inside such a vehicle to stabilize the camera, but it was longer than diameter of the wheels and thus simply too big. Besides, it would only serve its purpose if the camera was sitting in the very center of the wheels.

All in all, the vehicle was fun to play with, although the battery problems were annoying and the fast motors made it react very sharply to commands. I have used BSC unit instead of the SBrick specifically because it offered more accurate sliders for motors’ speed control, and I’ve ended up using a gamepad anyway, as steering with two sliders proved just too difficult.

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