BH1750FVI Ambient Light Sensor — ROS2 Jazzy Driver (I2C)

ROS2 Jazzy driver for the ROHM BH1750FVI digital ambient light sensor over I2C.

Features

• Publishes sensor_msgs/Illuminance on bh1750/illuminance
• fake_mode for testing without hardware (random Gaussian data)
• Three measurement modes: high (1 lx), high2 (0.5 lx), low (4 lx)
• 16-bit output, 1–65535 lux range
• Runtime publish_rate change via ros2 param set
• Calibration and reset services

Prerequisites

• ROS 2 Jazzy
• Python 3
• Real hardware only:
  • smbus2 (pip install smbus2)
  • BH1750FVI breakout board (I2C)

Installation

cd ~/ros2_ws
colcon build --packages-select bh1750_light --symlink-install
source install/setup.bash

Usage

Launch (fake mode — default)

ros2 launch bh1750_light bh1750_launch.py

Run node directly

ros2 run bh1750_light bh1750_node.py

Real hardware (Raspberry Pi)

ros2 launch bh1750_light bh1750_launch.py \
  params_file:=path/to/your_params.yaml

Set fake_mode: false and device_address in your YAML file.

Verify output

ros2 topic echo /bh1750/illuminance

Parameters

Parameter	Type	Default	Description
fake_mode	bool	true	Generate random data without hardware
i2c_bus	int	1	I2C bus number (/dev/i2c-N)
device_address	int	0x23	I2C address (ADDR=LOW: 0x23, ADDR=HIGH: 0x5C)
mode	string	high	Measurement mode: high (1 lx), high2 (0.5 lx), low (4 lx)
publish_rate	float	5.0	Publishing rate in Hz
frame_id	string	light_link	TF frame ID

Services

Service	Type	Description
bh1750/calibrate	std_srvs/srv/Trigger	Collect samples for 2 s, report averages
bh1750/reset	std_srvs/srv/Trigger	Clear bias, reinitialize sensor

Package Structure

bh1750_light/
├── CMakeLists.txt
├── package.xml
├── config/
│   └── bh1750_params.yaml
├── launch/
│   └── bh1750_launch.py
├── bh1750_light/
│   ├── __init__.py
│   └── bh1750_driver.py
├── nodes/
│   └── bh1750_node.py
├── test/
│   └── test_bh1750_node.py
├── .gitignore
├── LICENSE
├── CONTRIBUTING.md
└── README.md

Test Results

Tested on Ubuntu 24.04 (WSL2) with fake_mode: true.

Test Category	Test	Result
Topics	bh1750/illuminance publishes sensor_msgs/Illuminance	PASS
Topics	Illuminance non-negative, correct frame_id	PASS
Services	bh1750/calibrate returns success=True	PASS
Services	bh1750/reset returns success=True	PASS
Parameters	publish_rate runtime change	PASS
Shutdown	Clean exit	PASS
Linting	pep257, flake8, copyright, xmllint	PASS

License

MIT