WHEEL IN THE SKY - (PALACE GAMES)
Challenge: design and build an electro-mechanical ceiling mounted rotating color-wheel (The Wheel in the sky). the wheel’s speed, acceleration, and direction of rotation must be controllable programmatically via Raspberry Pi and Arduino microcontrollers. ADDITIONALLY the ABSOLUTE ORIENTATION must be KNOWN for game play implementation.
ten LUMINESCENT LED orbs were to be UNIFORMLY installed along the wheel’s outer circumference and the color emitted by the LED’s to SYNCHRONIze with the wheel’s orientation, conveying puzzle logic information to the players.
The wheel must operate smoothly, free of vibration, and quietly ENOUGH that any motor hum can not be heard from within the room.
Skills: 3D Printing, belt driven Power Transmission, C++/Arduino programming, Closed Loop feedback control, ELECTRICAL, hall effect SENSORS, Microcontrollers, motor control, Motor Driver, METAL WORKing, RGB led Control, SolidWorks CAD Modeling, welding.
SOLUTION: IN ORDER TO ACHIEVE CONTROL of THE WHEEL’S rotational speed and acceleration I wrote an arduino Program to regulate a DM860T digital stepper driver which actuates a NEMA 34 Stepper Motor, powering the wheel via V-Link 12:1 ratio Belt drive.
To sense the wheel’s absolute orientation and rotational direction I DESIGNED a positional feedback loop consisting of a permanent magnet aND an array of hall-effect sensors.
i DESIGNED AND 3d Printed a custom mount, securely attachING the magnet and allowing it to rotate in place a distance of 3-1/4 inches from the shaft,
The magnet in turn rotates CONCENTRICALLY inside a 3D printed ring I DESIGNED to house ten Uniformly distributed hall-effect sensors, each wired to a unique arduino input pin. As the wheel spins and the magnet passes by the sensors, absolute orientation (within the tolerance of 36 degrees) as well as rotational direction can be PRAGMATICALLY determined via the arduino.
To Solve for the color changing orbs, i mounted and wired LED NEOPIXEL JEWELS inside of plASTIC TRANSLUCENT SPHERES and wrote an arduino program to change to colors of each Jewel RELATIVE to the wheels ORIENTATION.
WHEEL IN THE SKY
This video shows the Wheel in The Sky in demo mode (constant speed, direction, and color).
I chose to support the shaft with a pillow block bearing because the mounting surface is parallel to the shaft, and because the enclosed back-to-back tapered roller bearing set is ideal for applications that undergo simultaneous radial and thrust forces.
To achieve basic global positioning I designed and 3D printed a ring that holds 10 evenly distributed hall effect sensors (seen above, left). I also 3D printed a collar that holds a permanent magnet and mounts directly onto shaft (seen above, right). When coaxially aligned the sensors detect if the magnet is near and act as an orientation feedback loop, which allows for programmed game logic to be executed based on the wheel’s position.
Having ran the RGB NeoPixel wires up through the drive shaft (shown above) I realized that I needed to incorporate a slip ring (shown below) to allow the connecting wires to rotate freely, without becoming wound up, as the pulley turns in either direction .
After completing the design and trouble shooting the mechanical components, I handed off the project to the game designers in December of 2019 for final game play-testing and programming.