Open Road Code

Documentation

Automotive Hardware I/O

Source: hardware_io/automotive/README.md

The hardware_io.automotive package contains low-level interfaces for automotive hardware. Code in this package owns device connections and raw device communication; it does not interpret vehicle data or implement application behavior.

Components

ELM327

elm327 communicates with ELM327-compatible diagnostic devices over a serial connection such as a Bluetooth RFCOMM device at /dev/rfcomm0.

from hardware_io.automotive.elm327 import Elm327Device

Layer Boundaries

  • hardware_io.automotive owns physical-device access and transport details.
  • protocols.obd2 owns OBD-II requests, normalized responses, and PID decoding.
  • controllers.automotive.obd2 coordinates devices and protocol models into vehicle state for applications.

Keeping these layers separate allows another OBD-II transport to reuse the protocol and controller code without depending on ELM327 command syntax.

Installation

The default host installer includes automotive support. To request only the automotive and ELM327 feature bundles explicitly, run:

scripts/host_setup.sh --feature automotive --feature elm327

The ELM327 feature installs pyserial. Bluetooth ELM327 devices also require the separate bluetooth feature and an established RFCOMM connection.

Decoded OBD-II Component Test

After the raw ELM327 component test succeeds, run the automotive controller test to request and decode live vehicle values:

python3 -m controllers.automotive.obd2.component_test.obd2_cli \
    --port /dev/rfcomm0

The controller test uses Elm327ObdAdapter to translate raw, header-enabled ELM327 output through protocols.can.CanFrame and into protocols.obd2.Obd2Response objects. It then uses Obd2Manager to decode supported PIDs and display values such as RPM, speed, temperatures, throttle position, and control-module voltage. Stop it with Ctrl+C.