How to Build a 3D-Printed Tire Pyrometer for Track Days

• Handheld pyrometer that probes tire surface temperature at three points and logs the data to a microSD card for post-session analysis
• ESP32-driven build with a K-type thermocouple probe, real-time clock, and a 4” TFT display, housed in a custom-printed PETG enclosure
• Firmware and CAD files are open source — this is a weekend electronics build, not a from-scratch design exercise

Purpose

Tire temperature is one of the clearest signals a track-day driver has for tuning grip: a hot center relative to the edges means overinflation, a cool center means underinflation, and uneven left-right readings point at alignment or camber issues. A pyrometer that logs readings automatically turns that signal into a dataset you can compare across sessions, instead of a number you have to remember and write down trackside.

Pre-requisites

• ESP32 DevKitC development board
• DS3231SN real-time clock module (I²C)
• MCP9601 thermocouple amplifier (I²C) and a K-type tire probe rated 0°C–200°C
• 4” TFT LCD (480×320, ILI9486 driver) and a microSD card slot
• Four AA batteries, a 1N5817 Schottky diode, three momentary pushbuttons, one latching pushbutton with LED
• FDM printer capable of PETG, plus heat-set brass threaded inserts
• Arduino IDE and a multimeter for continuity testing

Steps

1. Design and print the enclosure. Model the housing in CAD as four pieces — box, cover, battery box, battery cover — sized so the whole unit fits comfortably in one hand while the probe is held in the other. Print all four in PETG for heat and impact resistance.
2. Prep the housing. Heat-set the brass threaded inserts into the printed box, press in the battery terminals, and solder the Schottky diode to the positive battery terminal for reverse-polarity protection.
3. Lay out the electronics. Breadboard the ESP32, RTC, thermocouple amplifier, display, and buttons before soldering anything. Use consistent wire colors — red for 3.3V, black for ground, orange for 5V, blue/yellow for the I²C bus, green for chip-select lines — so the layout is traceable later.
4. Verify every connection with a multimeter. Check continuity on each button and each solder joint before final assembly. This is the step worth not rushing.
5. Mount the pushbuttons and wire the interface, then transfer the verified breadboard layout to a soldered PCB inside the enclosure.
6. Flash the firmware. Pull the code and config files from the project’s GitHub repo, install the required Arduino libraries, format the microSD card, and flash the ESP32 through the Arduino IDE.
7. Bench test before field use. Confirm the display initializes, both I²C devices respond, the microSD card mounts, and every button registers — in that order — before taking it to the track.

The Trap

Skipping continuity testing is the mistake that costs the most time later. A shorted-out button or a cold solder joint on the I²C bus is trivial to catch on a breadboard with a multimeter and painful to diagnose once everything is sealed inside a PETG enclosure with brass inserts. Test every connection before you commit to final assembly — not after the first time the display doesn’t turn on.

Cited References

• Race Car Tire Pyrometer — Make:
• MCP9601 Thermocouple Amplifier — Microchip
• DS3231 Real-Time Clock Module — Adafruit

Source: Make: DIY Projects and Ideas for Makers

Content created with AI assistance and reviewed for accuracy.