rpi_gpiozero_ros

ROS 2 Jazzy Python package for Raspberry Pi GPIO control using gpiozero.

Dependencies

• gpiozero
• ros_common_srvs

Supported gpiozero base classes

• DigitalInputDevice
• SmoothedInputDevice
• DigitalOutputDevice
• PWMOutputDevice
• Servo

Interfaces

• Publishes digital input state on ~/inputs/<name>/state (std_msgs/Bool)
• Publishes smoothed input value on ~/smoothed_inputs/<name>/value (std_msgs/Float32)
• Provides digital output service ~/outputs/<name>/set (std_srvs/SetBool)
• Provides PWM output service ~/pwm_outputs/<name>/set (ros_common_srvs/SetFloat32)
• Provides servo output service ~/servo_outputs/<name>/set (ros_common_srvs/SetFloat32)

Build

cd /path/to/workspace
colcon build --packages-select rpi_gpiozero_ros

Run

source install/setup.bash
ros2 launch rpi_gpiozero_ros gpiozero_node.launch.py

Parameter file

Parameters live under the node name (for example gpiozero_node) in ros__parameters:. See config/gpiozero_params.yaml.

Device parameters

Declare each device under gpio.<logical_name>.<field>. In YAML this is normally a nested map gpio: with one key per <logical_name>. ROS stores these as flat dotted parameters (for example gpio.button.pin).

There must be at least one configured device (type + pin per logical name).

Global parameters

Parameter	Type	Default	Description
pin_factory	string	auto	auto: use gpiozero’s default backend. mock: MockFactory with PWM-capable mock pins so pwm_output can run without a Pi.
pin_numbering	string	bcm	How each integer pin is turned into a gpiozero pin specification. See next subsection.
publish_rate_hz	float	20.0	Period for publishing all digital and smoothed input topics (1.0 / publish_rate_hz). Must be > 0.

If a device entry defines publish_rate_hz, it is validated (must be > 0) but publishing still uses the global publish_rate_hz timer only.

pin_numbering

Value	Example YAML pin	Passed to gpiozero
bcm	17	17 (integer BCM number)
gpio	17	"GPIO17"
board	11	"BOARD11" (header pin numbering)
wpi	0	"WPI0" (WiringPi style index; availability depends on backend)

gpio.<logical_name>.* — per-device fields

The map key <logical_name> becomes the device name in topics and services. Required for every entry: type and pin.

type	Extra fields	Notes
digital_input	pull_up (bool, optional) bounce_time (float, optional) active_state (bool, optional) publish_rate_hz (float, optional)	If pull_up is omitted and active_state is omitted, behaviour matches gpiozero pull-up default (pull_up=true). If you set active_state, you must omit pull_up; gpiozero does not allow both pull_up=true/false and a custom active_state. See also.
smoothed_input	queue_len (int, default 5) sample_wait (float, default 0.0) threshold (float, default 0.5) partial (bool, default false) publish_rate_hz (float, optional)	queue_len must be > 0; threshold in [0.0, 1.0].
digital_output	active_high (bool, default true) initial_value (bool, default false)
pwm_output	active_high (bool, default true) initial_value (float, default 0.0) frequency (float, default 100.0)	initial_value in [0.0, 1.0]; frequency must be > 0. On real Pi hardware, BCM PWM-capable pins restrictions still apply (same as gpiozero).
servo	initial_value (float, default 0.0) min_pulse_width (float, default 0.001) max_pulse_width (float, default 0.002) frame_width (float, default 0.02)	initial_value and service setpoint in [0.0, 1.0]; min_pulse_width > 0; max_pulse_width > min_pulse_width; frame_width > max_pulse_width. See gpiozero Servo.