TCS34725 RGB Color Sensor — ROS2 Jazzy Driver (I2C)

ROS2 Jazzy driver for the AMS TCS34725 RGB color sensor with IR blocking filter over I2C.

Features

• Publishes std_msgs/ColorRGBA on tcs34725/color (normalised R/G/B, clear as alpha)
• Publishes sensor_msgs/Illuminance on tcs34725/illuminance (lux via DN40 formula)
• fake_mode for testing without hardware (random Gaussian data)
• 4-channel sensing: Clear, Red, Green, Blue (16-bit each)
• IR blocking filter for accurate visible-light color measurement
• Configurable integration time: 2.4 ms ~ 700 ms
• Configurable gain: 1x, 4x, 16x, 60x
• 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)
  • TCS34725 breakout board (I2C)

Installation

cd ~/ros2_ws
colcon build --packages-select tcs34725_color --symlink-install
source install/setup.bash

Usage

Launch (fake mode — default)

ros2 launch tcs34725_color tcs34725_launch.py

Run node directly

ros2 run tcs34725_color tcs34725_node.py

Real hardware (Raspberry Pi)

ros2 launch tcs34725_color tcs34725_launch.py \
  params_file:=path/to/your_params.yaml

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

Verify output

ros2 topic echo /tcs34725/color
ros2 topic echo /tcs34725/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	0x29	I2C address (fixed for TCS34725)
integration	string	101ms	Integration time: 2.4ms, 24ms, 50ms, 101ms, 154ms, 700ms
gain	string	4x	Gain: 1x, 4x, 16x, 60x
publish_rate	float	5.0	Publishing rate in Hz
frame_id	string	color_link	TF frame ID (illuminance topic)

Topics

Topic	Type	Description
tcs34725/color	std_msgs/ColorRGBA	Normalised R/G/B (0-1), clear channel as alpha
tcs34725/illuminance	sensor_msgs/Illuminance	Lux from DN40 application note formula

Services

Service	Type	Description
tcs34725/calibrate	std_srvs/srv/Trigger	Collect samples for 2 s, report averages
tcs34725/reset	std_srvs/srv/Trigger	Clear bias, reinitialize sensor

Package Structure

tcs34725_color/
├── CMakeLists.txt
├── package.xml
├── config/
│   └── tcs34725_params.yaml
├── launch/
│   └── tcs34725_launch.py
├── tcs34725_color/
│   ├── __init__.py
│   └── tcs34725_driver.py
├── nodes/
│   └── tcs34725_node.py
├── test/
│   └── test_tcs34725_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	tcs34725/color publishes std_msgs/ColorRGBA	PASS
Topics	RGB values in 0.0-1.0 range	PASS
Topics	tcs34725/illuminance publishes sensor_msgs/Illuminance	PASS
Services	tcs34725/calibrate returns success=True	PASS
Services	tcs34725/reset returns success=True	PASS
Parameters	publish_rate runtime change	PASS
Shutdown	Clean exit	PASS
Linting	pep257, flake8, copyright, xmllint	PASS

License

MIT