Control Raspberry Pi GPIO pins with node.js
Please note that this project is not actively supported at present, due to real-life priorities and a lack of hardware to reliably test. It is unlikely that issues or pull requests will be dealt with for the forseeable future. This project was created in the early days of the Raspberry Pi and since then many others have sprung up, which you may have better luck with. Alternatively, as an open source project, please feel free to fork the project if it doesn't meet your needs.
rpi-gpio 1.x is no longer supported. Please use 2.x unless you need to run with an old version of node.
node version | rpi-gpio 1.x | rpi-gpio 2.x + |
---|---|---|
0.10 | Yes | No |
0.12 | Yes | No |
4 | Yes | Yes |
6 | Yes | Yes |
8 | Yes | Yes |
10 | No | Yes |
12 | No | Yes |
See this guide on how to get node.js running on Raspberry Pi.
This module can then be installed with npm:
npm install rpi-gpio
Please note that this module has a dependency on epoll and that currently it is only possible to build and develop the module on Linux systems.
If you are having trouble installing this module make sure you are running gcc/g++ -v 4.8
or higher. Here is an installation guide.
If you wish to use this module with Typescript, install the definitions from Definitely Typed:
npm install --save @types/rpi-gpio
Please note that this is not a Typescript project and the definitions are independently maintained by the community. Thanks to Roaders for providing these.
Before you can read or write, you must use setup()
to open a channel, and must specify whether it will be used for input or output. Having done this, you can then read in the state of the channel or write a value to it using read()
or write()
.
All of the functions relating to the pin state within this module are asynchronous, so where necessary - for example in reading the value of a channel - a callback must be provided. This module inherits the standard EventEmitter, so you may use its functions to listen to events.
Please be aware that there are multiple ways of referring to the pins on the Raspberry Pi. The simplest and default way to use the module is refer to them by physical position, using the diagrams on this page. So holding the Raspberry Pi such that the GPIO header runs down the upper-right side of the board, if you wished to address GPIO4 (which is in column 1 and row 4), you would setup pin 7. If you wish instead to refer to the pins by their GPIO names (known as BCM naming), you can use the setMode
command described in the API documentation below.
This module will work without use of the sudo
command, as long as the user running the node process belongs to the gpio
group. You can check the current user's groups by running the command groups
, or groups <user>
for another user. If you are not already a member of the gpio
group, you can add yourself or another user by running sudo adduser <user> gpio
.
The default API uses the node-style error-first callbacks to perform asynchronous functions. Most of these methods take a callback, and that callback should check for an error in its first argument. It is important to check for an error after each command, else your code will continue to run and will likely fail in hard to understand ways.
Sets up a channel for read or write. Must be done before the channel can be used.
Reads the value of a channel.
Writes the value of a channel.
Sets the channel addressing schema.
Alias of read().
Alias of write().
Tears down any previously set up channels. Should be run when your program stops, or needs to reset the state of the pins.
Tears down the module state - used for testing.
See Node EventEmitter for documentation on listening to events.
Emitted when the value of a channel changed
This API exposes a Promises interface to the module. All of the same functions are available, but do not take callbacks and instead return a Promise.
The Promises interface is available in the promise
namespace, e.g.:
var gpiop = require('rpi-gpio').promise;
gpiop.setup(7, gpiop.DIR_OUT)
.then(() => {
return gpiop.write(7, true)
})
.catch((err) => {
console.log('Error: ', err.toString())
})
See the examples
directory included in this project.
Please note that all examples are intended to be directly runnable from the code repository, so they always require the module in at the top using var gpio = require(../rpi-gpio)
. In reality, you will want to include the module using var gpio = require('rpi-gpio')
Contributions are always appreciated, whether that's in the form of bug reports, pull requests or helping to diagnose bugs and help other users on the issues page.
Due to the nature of this project it can be quite time-consuming to test against real hardware, so the automated test suite is all the more important. I will not accept any pull requests that cause the build to fail, and probably will not accept any that do not have corresponding test coverage.
You can run the tests with npm:
npm test
and create a coverage report with:
npm run coverage
There is also an integration test that you can run on Raspberry Pi hardware, having connected two GPIO pins across a resistor. The command to run the test will provide further instructions on how to set up the hardware:
npm run int
The tests use mochajs as the test framework, and Sinon.JS to stub and mock out file system calls.