This article details the development of a real-time automotive sensor dashboard by using an ELM327 OBD2 module and an ESP32-S3 touch display. The dashboard shows essential sensor data — including coolant temperature, battery voltage, oxygen sensor voltage, fuel economy, and engine load — retrieved directly from the vehicle’s ECU, offering instant, reliable diagnostics, and opportunities for future enhancements.

From Analog Gauges to Digital Insight

It all began one early morning, sitting in my 2001 Toyota Land Cruiser, waiting patiently as the engine warmed up. Watching the analog dials slowly climb, I wondered: Why rely on vague needles for crucial parameters like coolant temperature, battery voltage, or oil pressure (Figure 1)? Wouldn’t precise numeric values directly from the vehicle’s ECU be far more insightful? This simple thought sparked the idea of developing a custom OBD2 dashboard, directly tapping into the vehicle’s real-time sensor data via an ELM327 module and visualiz...