“The future depends on what you do today.”
Gandhi
Marble Run
The marble run is wirelessly controlled by the same weight-bearing platform that operated the Laser Gun.
However, with the marble run, Julian only needs to focus on maintaining a well-balanced stance. With the laser gun, performing multiple tasks—such as standing correctly, aiming, and shooting—proved challenging for him. He much prefers the simplicity and enjoyment of the marble run!
How it works
When Julian balances his weight evenly through both feet, the platform wirelessly releases marbles onto the run. Each marble earns points and rolls down one of eight tracks on a 1m x 1m masonite board. If his balance is off, the marbles are ejected and vanish through side slots.
At the top of the frame sits the marble dispenser, made from angled PVC tubing. The angled cut prevents the weight of the marbles from pressing down on the low-torque wooden servo below.
Every few seconds, if Julian is standing correctly, the servo is wirelessly activated. It slides a block back to catch a marble, then forward to drop it through a hole onto the top track of the run. The run features eight tracks. At the end of each, the marble hits a wall and drops to the next level.
Tracks 3 to 6 each have a hatch. When Julian stands correctly, the hatch covers stay closed, allowing the marble to continue down the run. If his balance is off, the hatches open, and the marble drops through an escape chute. There are two escape hatches on each side, controlled by two servos.
Points are awarded when marbles land on the first track and deducted when they fall through escape hatches. The score is shown on a blue four-digit seven-segment display.
Complete view
The marble run in complete view. It is 1X1 metre square. Has eight tracks from top to the bottom.
Marble dispenser
The diameter of slant cut PVC tube is large enough to hold one marble. The angle of the tube is such that it doesn't force too much pressure on the sliding block that moves the marbles into place and through the tube to the top track.
4*7 segment score counter
The counter gives Julian his points for good standing and removes points for off balance stances.
Conclusion and considerations
After putting so much care into the Laser Gun—only to realize it wasn’t quite right for Julian—I built the marble run quickly, without focusing on details. To avoid wasting time, I skipped flashy features like a marble lift or lights, focusing instead on proof of concept and usability. Ironically, now that he loves it, I wish I had made it much cooler!