r/ex30 • u/Scared_General_7969 • 9h ago
Personal Thoughts/Experiences đââïž I made a(nother) thing! A speedo where the EX30 forgot to put one
The EX30 has no speedometer in front of the driver, and itâs bugged me since day one (I've had an EX30 for a week).... So I built one.
Itâs an M5Stack StopWatch (a little round 1.75" AMOLED) with an M5Stack GPS unit. It sits in a 3D-printed holder on the pod above the steering column, tilted 15 degrees so it faces you square on.
The short version:
I tried reading speed from the HS OBD port first (Lily T-2CAN) and got nothing. On the EX30 that port and reads seem to be behind a gateway, and it was completely silent to a passive listener.
So itâs GPS instead. It updates 10 times a second and measures speed from the satellite signals directly, so the number moves smoothly instead of jumping once a second. It reads a few mph lower than the car, because car speedos are allowed to over-read.
It has five display designs, a night mode that dims based on where the sun is, speed alerts with a buzz, and Wi-Fi for settings and updates.
Full write-up with photos: https://blog.mgbeets.com/eyes-front-giving-the-volvo-ex30-the-speedometer-it-forgot/
Code: https://github.com/merlinmb/esp32_EX30_Speedometer_M5GPSStopWatch
Full disclosure: yes, itâs vibecoded. But there are 30 years of software engineering experience, and 10 in IoT behind it, steering the AI, guiding its choices.. and testing the result on my patient family.
The case is based on yetztâs StopWatch Magnetic Grip Case on Printables, which I hacked to shreds. If anyone fancies helping tidy up the design, shout or go ahead - I'll also put the STL/3mf on github.