VEML7700 High-Accuracy Ambient Light Sensor — ROS2 Jazzy Driver (I2C)

ROS2 Jazzy driver for the Vishay VEML7700 high-accuracy ambient light sensor over I2C.

Features

• Publishes sensor_msgs/Illuminance on veml7700/illuminance
• fake_mode for testing without hardware (random Gaussian data)
• Wide dynamic range: 0.0036 ~ 120000 lux
• Configurable gain: 1x, 2x, 1/8x, 1/4x
• Configurable integration time: 25 ms ~ 800 ms
• High-lux polynomial correction (Vishay application note)
• Runtime publish_rate change via ros2 param set
• Calibration and reset services

Why this package?

There is also a bh1750_light driver for BH1750. The VEML7700 offers different trade-offs:

Feature	BH1750 (bh1750_light)	VEML7700 (this package)
Lux range	1–65535 lx	0.0036–120000 lx
Resolution	1 / 0.5 / 4 lx	0.0036 lx (best)
Gain	Fixed per mode	1x / 2x / 1/8x / 1/4x
Integration	Fixed per mode	25–800 ms
High-lux correction	Not needed	Polynomial correction
White channel	No	Yes
Price	~$1-2	~$3-5

Choose bh1750_light for simple, low-cost lux readings. Choose this package for wide dynamic range and high accuracy.

Prerequisites

• ROS 2 Jazzy
• Python 3
• Real hardware only:
  • smbus2 (pip install smbus2)
  • VEML7700 breakout board (I2C)

Installation

cd ~/ros2_ws
colcon build --packages-select veml7700_light --symlink-install
source install/setup.bash

Usage

Launch (fake mode — default)

ros2 launch veml7700_light veml7700_launch.py

Run node directly

ros2 run veml7700_light veml7700_node.py

Real hardware (Raspberry Pi)

ros2 launch veml7700_light veml7700_launch.py \
  params_file:=path/to/your_params.yaml

Set fake_mode: false, gain, and integration in your YAML file.

Verify output

ros2 topic echo /veml7700/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	0x10	I2C address (fixed for VEML7700)
gain	string	1x	Gain: 1x, 2x, 1/8x, 1/4x
integration	string	100ms	Integration time: 25ms, 50ms, 100ms, 200ms, 400ms, 800ms
publish_rate	float	5.0	Publishing rate in Hz
frame_id	string	light_link	TF frame ID

Services

Service	Type	Description
veml7700/calibrate	std_srvs/srv/Trigger	Collect samples for 2 s, report averages
veml7700/reset	std_srvs/srv/Trigger	Clear bias, reinitialize sensor

Package Structure

veml7700_light/
├── CMakeLists.txt
├── package.xml
├── config/
│   └── veml7700_params.yaml
├── launch/
│   └── veml7700_launch.py
├── veml7700_light/
│   ├── __init__.py
│   └── veml7700_driver.py
├── nodes/
│   └── veml7700_node.py
├── test/
│   └── test_veml7700_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	veml7700/illuminance publishes sensor_msgs/Illuminance	PASS
Topics	Illuminance non-negative, correct frame_id	PASS
Services	veml7700/calibrate returns success=True	PASS
Services	veml7700/reset returns success=True	PASS
Parameters	publish_rate runtime change	PASS
Shutdown	Clean exit	PASS
Linting	pep257, flake8, copyright, xmllint	PASS

License

MIT