rpi-backlight 2.0.0b2

A Python module for controlling power and brightness of the official Raspberry Pi 7" touch display.

rpi-backlight

A Python module for controlling power and brightness of the official Raspberry Pi 7" touch display.

Note: This GIF was created using the old v1 API, so please don't use it as API reference 🙂

Features

• Change the display brightness smoothly or abrupt
• Set the display power on or off
• Get the current brightness
• Get the maximum brightness
• Get the display power state (on/off)
• Command line interface
• Graphical user interface

Requirements

• A Raspberry Pi including a correctly assembled 7" touch display v1.1 or higher running a Linux-based OS
• Python 3.5+
• Optional: pygobject for the GUI, already installed on a recent Raspbian

Installation

Install from PyPI:

$ pip3 install rpi-backlight

Note: You may need to change the backlight rules file in order to run the code:

$ echo 'SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power"' | sudo tee -a /etc/udev/rules.d/backlight-permissions.rules

Emulator

For testing without a physical display (e.g. on your main Linux/macOS/Windows machine) you can use linusg/rpi-backlight-emulator.

Usage

API

Example in a Python shell:

>>> from rpi_backlight import Backlight
>>>
>>> backlight = Backlight()
>>> backlight.brightness
100
>>> backlight.brightness = 50
>>> backlight.brightness
50
>>>
>>> with backlight.fade(duration=1):
...     backlight.brightness = 0
...
>>> backlight.fade_duration = 0.5
>>> # subsequent `backlight.brightness = x` will fade 500ms
>>>
>>> backlight.power
True
>>> backlight.power = False
>>> backlight.power
False
>>>

NOTE: Code using set_ functions of this library has to be run as root, e.g. sudo python3 file.py, if the permissions for changing the backlight were not changed as described in the installation section!

CLI

Open a terminal and run rpi-backlight:

$ rpi-backlight -b 100
$ rpi-backlight -b 20 -d 1
$ rpi-backlight --brightness
20
$ rpi-backlight --power
on
$ rpi-backlight --power off
$ rpi-backlight --power
off

Available flags:

• -b / --brightness - get/set brightness
• -p / --power - get/set power on/off
• -d / --duration - use in combination with -b / --brightness to fade the brightness

GUI

Open a terminal and run rpi-backlight-gui.

Adding a shortcut to the LXDE panel

First, create a .desktop file for rpi-backlight (e.g. /home/pi/.local/share/applications/rpi-backlight.desktop) with the following content:

[Desktop Entry]
Version=1.0
Type=Application
Terminal=false
Name=rpi-backlight GUI
Exec=/home/pi/.local/bin/rpi-backlight-gui
Icon=/usr/share/icons/HighContrast/256x256/status/display-brightness.png
Categories=Utility;

The absolute path to rpi-backlight-gui might differ if you did not follow the installation instructions above, e.g. installed as root.

Make it executable:

$ chmod +x /home/pi/.local/share/applications/rpi-backlight.desktop

You should now be able to start the rpi-backlight GUI from the menu: (Raspberry pi Logo) → Accessoires → rpi-backlight GUI.

Next, right-click on the panel and choose Add / Remove panel items. Select Application Launch Bar and click Preferences:

Select rpi-backlight GUI on the right and click Add:

You're done! The result should look like this:

Tests

Tests use pytest, install with pip3 install pytest.

Now, run from the repository root directory:

$ python3 -m pytest

Todo

I'm currently finalizing the 2.0.0 API and rebuilding the CLI - feel free to open an issue for bug reports and to discuss new features!

External Links

• rpi-backlight-emulator
• Travis CI: Build tests
• readthedocs.org: Documentation

License

The source code and all other files in this repository are licensed under the MIT license, so you can easily use it in your own projects. See LICENSE for more information.