LEO Medusa: What If Creating Large-scale Electronics Projects Took No Experience?

The idea came up when I was working on a sculpture for LEO which stands for Light Embodied Odysseys which is a project that combines architecture and technology to create large sculptures to capture human emotions and improve quality of life through artistic solutions.

When working on a LEO sculpture that needed around 48 LEDs that had to be controlled seemingly with each other, it became clear that a single Micro:bit which could only control 17 pins was nowhere near enough and managing wires or data across multiple different microcontrollers was going to be unorganized.

This created a need for a smarter solution that could control far more outputs from a single microcontroller without the mess of managing multiple devices.

Similar large-scale projects within LEO are often out of reach for beginners due to being too expensive, too complex, or both. LEO Medusa aims to change that.

Customization needs to be a key part of the design resistors and components have to be able to be swapped out easily in an organized, centralized way, allowing the same board to be adapted for different voltages and components in order to accommodate future LEO sculptures.

Started with a simple breadboard prototype at 3.3V to validate the basic concept of controlling multiple outputs from one microcontroller.

Updated the design to 12V and built a larger 2x2 breadboard version to confirm the higher voltage design worked correctly.

Schematics were developed alongside breadboard testing in Altium Designer, using N-channel and P-channel MOSFETs to allow the board to operate above the Micro:bit's 3.3V logic level.

Once the schematic was finalized, the PCB layout was designed in Altium in a circular form factor to better fit into larger sculptural installations.

After fabrication, LEDs were tested with different resistor values to find the right balance of brightness and current at 12V.

The PCB uses matrix multiplexing in order to achieve a x:x^2 (16:64) ratio. Instead of each output pin from a microbit controlling an LED, they are divided into 2 groups controlling a 2-dimensional 8x8 coordinate system, which gets mapped out by the PCB and connected to 64 output terminals.

A 20mA LED with a 200 ohm resistor was predicted to get 0.02x200= 4V (V=IR), the actual voltage was recorded using various methods through Pasco sensors, multimeters, and most successfully through an oscilloscope, which showed peaks of around 3.9V and a floor of 1.9V in between cycling the 8 columns.

The board was tested on previous LEO sculptures and components to verify real performance.

We partnered with the Living Architecture  Systems Group from the University of Waterloo to integrate a spatial behavior software platform called “Aether” into the PCB. It was a control interface to expand compatibility beyond Micro:bit block coding to an even simpler, more intuitive program coded in C++.

The LEO Medusa was able to control 64 output pins using only 16 GPIO pins through an 8x8 multiplexed matrix design with correct peak voltages. The board worked on the first fabrication with minimal hardware corrections needed.

The board proved compatible with a wide range of components and was tested on white 3V LEDs, 12V LEDs, 12V LED Neo strips, and Adafruit noods LEDs, requiring only different resistor values to suit each component.

The Oscilloscope testing revealed some expected behavior of fast-switching matrix designs, including minor voltage irregularities during switching potentially due to special MOSFET properties, parasitic current or capacitive coupling. The 1/8 duty cycle limits the ability to include motors that don't run on 12V.

The Micro:bit block coding interface was straightforward to adapt depending on the project, other microcontrollers using different coding languages could also be swapped in.

LEO Medusa was tested in the lights of the Primordial Neo-Cyber Nor which is a real LEO sculpture, where it performed as expected in a large-scale artistic installation. The circular PCB fits well within the sculpture's aesthetic, and the 3D printed frame kept wiring secure and organized.

Additionally, LEO Medusa became the first successful beta test of Aether outside of its original development team which is a spatial behavior software platform. This showed significant promise for expanding the board's compatibility beyond Micro:bit block coding to an even more intuitive and simple coding software with artificial intelligence capabilities.

Before LEO Medusa existed, setting up even a simple 3x3 LED grid on a breadboard took significantly longer than soldering and attaching components directly to the 8x8 PCB. With the 3D printed attachment, wires are protected from unwanted disconnection, short circuits, and general messiness. Medusa gives the user a clean, centralized, and organized board that a beginner can use.

This changes what LEO projects can look like in the future. Previously, contributing meaningfully to a LEO installation required some background or training in computer science or electronics. Now, people with completely different areas of expertise from artists, designers to architects can participate and contribute without being held back by technical barriers. LEO will become a more inclusive and collaborative project as a result.

Beyond LEO, this board has potential applications for any electronics learner, artist, or creative person who wants to build something large-scale without years of technical experience.

This project could show that quality of life improvement technology can create more meaningful creative experiences. When students don't have to spend all their time troubleshooting wiring, they can spend more time creating. The ability to feel the impact of their work can be done faster.

A column of GPIO pins may be separated from the matrix to run motors without the limitations of the 1/8 duty cycle. Voltage irregularities should also be stabilized with further research.

Smaller and more precise components could be used to make the board more compact via surface mount instead of through-hole.

Deeper integration with Aether will be developed with more sophisticated AI and customization capabilities.

Micro:bit code will be optimized using arrays and lists to further simplify the coding process on block code.

LEO Medusa will continue to be integrated into future LEO projects under other students.

Huge thanks to my supervising teacher, Ian Fogarty, as well as the Living Architecture Systems Group for supporting and mentoring my journey.

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