Open RC Spotter: An ESP32 Data Logger for RC Car Racing

#esp32 #gps #imu #datalogger

What if your RC car could hand you the same telemetry a MotoGP crew pores over after every lap? That is the gap Open RC Spotter fills. It is an open-source data logger built by Jake Wachlin of Energy Labs for RC cars and other radio-controlled vehicles, and it treats a hobby car like a real race machine.

What it actually records

Open RC Spotter captures a synchronized log of nearly everything happening during a run: GPS position and speed, acceleration, gyroscope and IMU force vectors, steering and throttle PWM inputs, battery voltage, motor temperature, and ESC temperature. After a session you load that log into the self-hosted Open RC Crew Chief web app and see exactly where you scrubbed speed in a corner or cooked the motor. This is the RC-scale version of the data acquisition gear bolted into a full-size race car, not a toy accessory.

The technical answer: what is on the board

The whole logger is built around an ESP32-WROOM-32E-N4 module, so there is headroom for both storage and wireless. Sensing comes from three parts every maker will recognize: an LSM6DS six-axis IMU for motion, a u-blox MAX-M10S GPS receiver for position and speed, and an ADS1115 16-bit ADC to read the analog channels cleanly. Logged data drops onto a standard SD card, and Wachlin recommends a Class 10 card so writes keep pace at speed. Want live numbers instead of post-run analysis? Wire a second ESP32 to the Spotter as a receiver over its serial pins. The board itself is a small unenclosed PCB you mount near the car's control electronics, so it adds almost no weight.

Try it on your own bench

You have two paths. Buy the finished board on Tindie for about $169 (out of stock at the moment), or pull the design files from Wachlin's GitHub and build your own. Rolling your own means sourcing the ESP32, the LSM6DS, the MAX-M10S, and the ADS1115, soldering them to the PCB, and flashing the firmware. Read the original write-up on Hackster first, then grab the repo. One gotcha: if the GPS never locks indoors, that is expected, so take it outside for a clear sky view before you go hunting for a wiring fault.

Originally published on blog.circuit.rocks.