The system consists of two devices:
- OBD2 Station – plugged into the vehicle diagnostic port
- Display Station – receives data via BLE and presents it to the user
- Plug the device into the vehicle’s OBD2 port.
- After a few seconds, the green LED will start blinking – this indicates proper CAN bus communication.
If the LED does not blink:
- make sure the ignition is turned ON,
- verify that the vehicle supports OBD2 over CAN.
- Connect the device via USB power.
- After startup, it will automatically begin scanning for BLE devices.
- Once connected, a BLE icon will appear on the screen.
If the BLE icon does not appear:
- ensure the OBD2 station is powered and connected,
- check that both devices are within range (a few meters).
The screen presents:
- Current vehicle speed
- Engine RPM
- Instant fuel consumption
- Average fuel consumption
- Traveled distance
- Fuel used
- Current date and time
A Reset button is located at the bottom of the screen.
Pressing it resets:
- average fuel consumption
- traveled distance
- fuel used
- Speed – km/h
- Engine RPM – revolutions per minute
- Driving fuel consumption – l/100 km
- Idle fuel consumption – l/h
- Not all vehicles provide all PID parameters.
- Some newer vehicles may restrict access to certain data (e.g., intake temperature).
- In older vehicles, fuel consumption may be calculated approximately (formula-based).
The vehicle must:
- have an OBD2 connector,
- support CAN communication (ISO 15765-4),
- have ignition turned ON.
- OBD2 Station → BLE Peripheral (server)
- Display Station → BLE Central (client)
The connection is established automatically after both devices are powered on.
Car → OBD2 → CAN → ESP32 → BLE → ESP32 → Display
The system operates in a closed ecosystem and does not require:
- a smartphone,
- a mobile application,
- internet access.
Possible future extensions:
- DTC reading and clearing
- Extended diagnostic parameters
- Historical data logging