LED Rubik’s Cube Team 54: Meghan LeMay & Michael Rupp TA: Bryce Smith

Problem Statement There is no way for a user to reset a Rubik’s Cube without completely solving the puzzle.

Nomenclature “Cube” refers to entire Rubik’s Cube “Block” refers to smaller cubes that make up the “cube”

Fast Facts The cube is comprised of 26 blocks. Each of the six colors represents the initial state of one of the cube’s faces. Each center block is stationary and can only rotate. In our project, we have an RGB LED representing each face of each block visible to the user.

High-level Requirements Rotation Reset Low Power Consumption

Physical Implementation

Rotation Mechanism

Design Considerations No wires between blocks RGB LEDs must change color on demand Power to each block

Power Problem Solutions Metal Contacts Wireless Power Each block individually powered

Proposed Solutions Gyroscope/accelerometer with arrays of transmitters and receivers Optical communication in IR band

Center Blocks Responsible for initiating reset sequence using microphone Propagate reset signal to side blocks using infrared LEDs Never change color

Block Diagram of Center Blocks

Center Block PCBs

Microphone Reads 1 kHz sine wave Autocorrelation Peak detection

Microphone – Voltage vs Time

IR Transmission IR spectrum does not interfere with RGB LEDs 940 nm IR LEDs 20 ms pulses

IR LED Timing Diagrams

RV: IR LED

Side Blocks Contains infrared transmitters and receivers Receives reset signal from center block Send reset signal to corner RGB LEDs on two faces

Block Diagram of Side Blocks

Side Block PCBs

Photodiode – Voltage vs Time

Corner Blocks Contains infrared receivers Receives reset signal from side blocks RGB LEDs on three faces

Block Diagram of Corner Blocks

Corner Block PCBs

So what went wrong…?

26 Total PCBs…

Fixes We Made Extra grounds to attach last minute components Filing the corners of PCBs to allow them to fit in blocks

Conclusions Successful proof of concept! Further work must include more consideration of the mechanical constraints. Implementation of “pseudorandom” reset could be achieved with further programming work.

Questions?