Connecting your car to the Internet of Things (IoT) unlocks a wealth of data and possibilities. By leveraging the power of OBD2 and MQTT, you can seamlessly integrate your vehicle’s diagnostics with Home Assistant, opening up a world of automation and insights. This guide provides a comprehensive overview of setting up an Obd2 Mqtt gateway for Home Assistant, enabling real-time vehicle data monitoring and control.
Essential Components for OBD2 MQTT Integration
Building an OBD2 MQTT gateway requires several key components:
- Home Assistant with Mosquitto Broker: Home Assistant acts as the central hub for your smart home, while Mosquitto Broker facilitates communication via the MQTT protocol.
- ESP32 with SIM800L or A7670: An ESP32 microcontroller with a cellular modem (SIM800L or A7670) provides the brains and connectivity for the gateway.
- ELM327 OBD Bluetooth Adapter: This adapter connects to your car’s OBD2 port and translates vehicle data into a format the ESP32 can understand. Any compatible adapter will work.
- SIM Card with Data Plan: A SIM card with an active data plan enables the ESP32 to connect to the internet and publish data to the MQTT broker.
- A Car: Lastly, you’ll need a vehicle equipped with an OBD2 port (most cars manufactured after 1996).
Supported Hardware for your OBD2 MQTT Gateway
The following table outlines compatible hardware and their respective environments, SSL/TLS support, and 3D-printed case options:
| Product | Environment | SSL/TLS | Case |
|---|---|---|---|
| T-Call SIM800L | SIM800L_IP5306_VERSION_20190610 SIM800L_IP5306_VERSION_20200811 | ❌ (only SSL 2/3, TLS 1.0/1.2) | Case |
| T-Call SIM800C | SIM800L_AXP192_VERSION_20200327SIM800C_AXP192_VERSION_20200609 | ❌ (only SSL 2/3, TLS 1.0/1.2) | Case |
| T-Call A7670 | T-Call-A7670X-V1-0T-Call-A7670X-V1-1 | ✅ | Case with internal GPS/LTECase with external GPS/LTE |
| T-A7670E/G/SA R2 | T-A7670X | ✅ | Case with internal GPS/LTECase with external GPS/LTE |
| T-A7670E/G/SA R2 without GPS | T-A7670X-NO-GPS | ✅ | Case |
| T-A7670G with GPS Shield | T-A7670X-GPS-SHIELD | ✅ | Case with internal GPS/LTECase with external GPS/LTE |
Deployment and Configuration of your OBD2 MQTT Gateway
Simplified Setup with Web Installer
For a streamlined setup process, utilize the provided web installer: Web Installer. This simplifies the process of flashing the ESP32 and configuring the device.
Manual Build and Upload using PlatformIO
Alternatively, for more advanced users, you can manually build and upload the firmware using PlatformIO:
Building the Firmware:
pio run [-e OPTIONAL ENV]
pio run --target buildfs [-e OPTIONAL ENV]Uploading the Firmware:
pio run --target upload -e T-Call-A7670X-V1-0Customizing OBD2 Data with Custom States
The real power of this setup lies in its customization. You can define custom OBD2 states to monitor specific parameters and calculations. These states can be READ directly from the vehicle’s OBD2 port or CALCULATED using existing data points.
Defining READ States
READ states retrieve raw data from the vehicle using predefined functions or by specifying PID codes.
Defining CALC States
CALC states allow you to perform calculations on existing data, enabling derived metrics and complex logic. This uses a powerful expression language with predefined variables and functions.
Conclusion: Unleashing the Potential of OBD2 Data with MQTT
By implementing this OBD2 MQTT solution, you gain access to a wealth of real-time vehicle data within Home Assistant. This enables you to create automations, monitor vehicle health, track fuel consumption, and much more. The flexible customization options ensure you can tailor the system to your specific needs and unlock the full potential of your vehicle’s data.
