Ayushmaan Bhardwaj's TURN-OFF Is a Minimal, Espressif ESP32-Powered Bike Navigator — Sans GPS
With little more than an ESP32-S3 and a battery, how do you handle turn-by-turn navigation and routing? By connecting it to your phone.
Electrical and electronics engineer Ayushmaan Bhardwaj has turned a compact smart display built around Espressif's ESP32-S3 into a minimalist Global Positioning System (GPS) satellite navigator for bikes: the TURN-OFF.
"The original thought was pretty simple: 'What if I could make a tiny navigation display for my bicycle instead of mounting my entire phone on the handlebar,'" Bhardwaj explains of the project's origins. "Using a phone while cycling always felt awkward to me. It's bulky, distracting, drains battery quickly, and just makes the whole setup look messy. I wanted something smaller and cleaner that only focused on navigation, almost like a tiny futuristic bike computer. That’s how TURN-OFF started."
The heart of the TURN-OFF is a Waveshare ESP32-S3 1.69" smart display, which — as the name suggests — includes an integrated Espressif ESP32-S3 wireless microcontroller. Aside from a lithium-polymer battery and mounting hardware, though, you won't find much else inside the 3D-printed enclosure — and you won't find a Global Navigation Satellite System (GNSS) receiver either. "I intentionally tried to keep the hardware minimal," Bhardwaj explains, "and pushed most of the heavy work like routing, GPS handling, and navigation logic to the phone side instead."
The idea is simple: the smart display mounts to the bike as a easily-glanceable display for turn notifications — but the actual navigation is handled by the user's smartphone, using its integrated GNSS receiver and Wi-Fi radio via a custom web app. "The web app itself was built using HTML, CSS, and JavaScript," Bhardwaj notes. "For destination search, I used Nominatim (OpenStreetMap), while route generation is handled using the OpenRouteService API [Application Programming Interface]. Once navigation starts, the phone continuously sends live navigation updates to the ESP32 wirelessly using WebSockets."
The full project write-up is available on Instructables, along with 3D print files, a bill of materials, and the source code required to build your own.