RPi-GPIO

A ROS node for managing GPIO pins on a Raspberry Pi

Disclaimer

This code was developed and tested under ROS Indigo on Ubuntu 14.04. This is research code, and any fitness for a particular purpose is disclaimed.

Installation

Create an overlay workspace and clone the code like:

mkdir -p /path/to/your/overlay/src
cd /path/to/your/overlay/src
git clone https://github.com/chrisspen/rpi_gpio.git
source /opt/ros/indigo/setup.bash
cd ..
catkin_make

Then, when initializing your shell environment for your main workspace, ensure you source this overlay like:

cd /path/to/your/main/workspace
source ./devel/setup.sh
source /path/to/your/overlay/devel/setup.bash
catkin_make

Usage

Run with:

rosrun rpi_gpio rpi_gpio_node.py

or:

roslaunch rpi_gpio rpi_gpio.launch

See config/example.yaml for an illustration of parameters accepted.

Three basic parameters are available:

1. directions: A hash listing which pins are inputs (in) or outputs (out). Any pin not listed here will be assumed not in use and will not be managed by the node.
2. states: A hash listing the initial state of each output pin.
3. shutdown_states: A hash listing the state to set output pins to before safely shutting down.

Once running, you can set pins states from the command line with:

rosservice call /rpi_gpio/set_pin 21 1
rosservice call /rpi_gpio/set_pin 21 0

Or by calling the service from Python like:

from rpi_gpio.srv import DigitalWrite
rpi_gpio = rospy.ServiceProxy('/rpi_gpio/set_pin', DigitalWrite)
pin = 21
state = 1
rpi_gpio(pin, state)