Friday, November 15, 2013

Little Red Box

Dimensions: length/width/height IN - 6.3/6.3/4.75.  CM - 14.4/14.4/9.4
Weight: 0.5 lb
Power: Power Functions rechargeable battery
Propulsion: 1x PF M motor
Steering: PF servo motor
Built: Early May 2013 

The goal with this MOC was to make an ultra-compact, drivable and steerable  vehicle base, with a brick built housing. I thought it would be funny to see a little red brick cube start driving around :). After just an hour or so of building, I had a functional design. And after some improvements, it looked like this:

The steering motor was attached to a connector plate, (left) which was mounted on a stud jumper (right). This way the motor was as close up against the battery as possible, although it was still a bit off center with the rest of the base.

Since both the Servo motor and the steering mechanism have to be at perfect right angles in their neutral position, the wheels don't return to center perfectly.
I decided to use the servo motor anyway, as the return to center function is still convenient. And I can use the speed remote control for proportional control, which can remedy the problem of the wheels being off-center.

For the propulsion, I again created the simplest solution I could, with an M-motor directly over the wheels. (Note. The image above and the final version are slightly different, as can be seen in the video.)

I decided to attach the cover by having a mostly flat plate over most of the model.
Most of the base came out as a rather irregular shape, and there's a good bit of empty space with the cover on. So no doubt a smaller RC cube can be made.

Additional photos:

Figures are to scale.

Video: Lego Motorized Red Box - Youtube  (Looks much better in HD.)