Leon Furze

Innovation often springs from frustration with the status quo. For developer Miroslav Kotalík, the limitations of existing augmented reality (AR) glasses kickstarted a journey to create something better. After I saw a post about Kotalík’s impressive DIY AR glasses, which he has called “Zero”, I reached out to him on X and asked if he’d answer a few questions.

“I built Zero because I didn’t like any of the AR glasses currently on the market,” he explains. “Most AR glasses are offset from your face due to the birdbath optics, and I hated it. They mostly need a phone to function, often connect over a wire, and also feel unbalanced or heavy.”

The first breakthrough came from an unexpected moment of inspiration. “Using the ingenious method of turning my head awkwardly in front of a camera, I realised there’s unused space inside a normal pair of glasses near the hinge on both sides,” he recalls. “A flash of Jamie Hyneman’s side-covered goggles appeared in my head. I immediately started sketching a design filling this unused space with optics. It all just made sense.”

The first prototype came together quickly. “The same day, I designed and printed a model of such a frame. I put a hole in the side to fit optics from an astronomical telescope eyepiece to collimate light rays from a display connected to Arduino. I cut a piece of transparent acrylic off a very old graphics card fan cover to use as the combinator. Then I wrote some quick Arduino code to display text, turned it on, and it worked!”

The path to miniaturisation proved a little more challenging. “I used free optics simulation software called Ray Optics Simulation to determine the needed lens shape. I reloaded my 3D printer with transparent PETG filament and tweaked the settings for days until I got the most transparent FDM 3D print I could make.” However, this approach hit a roadblock: “No matter what I’d done, the lens kept air gaps in the print lines, making it unusable, even when the rest was perfectly clear.”

The solution came through casting: “I bought clear resin and 3D-printed just the molds. After multiple days of repeated curing, sanding, and polishing, I got it! The first usable lens.” With this breakthrough, he continued: “I got a pair of tiny SPI display modules, made a housing, fitted everything in, and wow, the optics worked, making the display reflection in focus without straining my eyes.”

The software development was equally innovative. “Thanks to the brilliant fbcp-ili9341 GitHub repository, I built a driver for this specific SPI display. This allowed me to show the desktop in real-time, low latency at 60FPS through SPI on a Raspberry Pi.” The entire frame was designed using Tinkercad, which Kotalík notes was limited but accessible, making “everything so much easier.” Many schools use Tinkercad in STEM programs due to its accessibility and ease-of-use: I remember using it myself as part of a Year 9 STEAM program when we first bought 3D printers back in 2020.

The choice of a Raspberry Pi Zero as the brain of the device was also strategic. “Using a Raspberry Pi was crucial,” he explains. “Arduino or ESP32-based boards could display text or images on an SPI screen, but I already thought about the future—if the device made it into the hands of developers, no one would be interested in writing very specific, ultra-optimized system-level software.” Instead, he opted for “a much more developer-friendly approach… making the goggles run a Linux system and letting developers build on top of the web app layer I made.”

The UI design prioritizes practicality and discretion. “I want people to not wave their hands around in the air to move across apps in public,” he notes. “When you boot up the device, you see a floating panel in front of you with all the apps laid out. I enabled 3DoF tracking with an accelerometer, so the user can select and click UI elements just by looking around. It’s similar to what Apple Vision Pro does, but using the whole head instead of just the eyes.”

Looking toward the future, Kotalík’s version 2.0 promises significant improvements. “I want the device to track itself in 6DoF. For that, it needs a camera, and also a GPS module for world tracking. A camera will also enable hand tracking and AI recognition.” His additional plans include “speakers and a microphone to enable video calling and media consumption without needing headphones,” larger combiners for 30% better field of view, dual batteries for wireless operation, and a more powerful computer for enhanced processing capabilities.

He sees tremendous potential for AR in education: “You can have shared class experiences where students learn from virtual objects right in front of them, whether it’s animals, chemical bonds, or the solar system.” The open architecture of Zero could enable students to “not only learn with the glasses but also from the glasses… hack together their own apps, develop their own hardware add-ons, or even build a pair from scratch.”

For those interested in following a similar path, Kotalík emphasizes the importance of “first principles” thinking: “First, evaluate if the desired result is physically possible. If the answer is yes, break it down into a series of tasks. Then execute. Don’t fear taking on big tasks.” He encourages learning through doing, noting that he “started making Zero without knowing anything about optics. When it came to it, I searched and asked and experimented and eventually got the result I needed to move to the next task.”

His advice for aspiring creators is refreshingly simple: “To make something, just grab a Pi or Arduino and take on the project of your dreams. Eventually, you will make it.”

Personally, I can’t wait to see what happens next with this project. As soon as I saw the original article, it triggered memories of my own experiences teaching STEM and the curiosity and excitement of students working in the lab with Raspberry Pis and 3D printers.. I’m sure version 2 will be even more impressive!

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