Frederik Lindenaar
89436aa586
- added systemd service descriptors - new features in gpio_trigger.py: - support waiting for a hold period (-H) - added option to ignore command's result code (-i) - added variable subtitution in the arguments (%PIN% and %STATE%)
110 lines
4.5 KiB
Markdown
110 lines
4.5 KiB
Markdown
Raspberry Pi Scripts
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====================
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This repository contains my collection of scripts and other snippets for the
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[Raspberry Pi](https://www.raspberrypi.org). I am publishing these in case they
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are of any benefit to other enthusiasts. Use them freely and please let me know
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in case you encounter any issues or require changes.
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The latest versions, documentation and bugtracker available on my
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[GitLab instance](https://gitlab.lindenaar.net/scripts/raspberrypi)
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Copyright (c) 2019 Frederik Lindenaar. free for distribution under
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the GNU General Public License, see [below](#license)
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Contents
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========
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This repository contains the following scripts:
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* [gpio_trigger.py](#gpio_trigger)
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is s script to execute a command when a GPIO input pin changes
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* [rpi_no_hdmi.service](#services)
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is a systemd service to disable the Raspberry Pi's HDMI port at boot
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* [rpi_no_usb.service](#services)
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is a systemd service to disable the Raspberry Pi's USB bus at boot
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* [rpi_no_wifi.service](#services)
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is a systemd service to disable on-board WiFi on Raspberry Pi at boot
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* [rpi_poweroff_button.service](#services)
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is a systemd service to support a power-off button using [gpio_trigger.py](#gpio_trigger)
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<a name=gpio_trigger>gpio_trigger.py</a>
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----------------------------------------
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This script was initially written to add a power-off button to a Raspberry Pi,
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[see this blog post](https://frederik.lindenaar.nl/2019/10/23/raspberry-pi-power-off-button.html)
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for the rationale behind it and how to construct and connect a physical button.
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The script itself is a generic solution to monitor a GPIO pin and executes a
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command when the input signal on a pin changes. It can run as interactively as
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well as in the background and executes a command once or continuously upon any
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change or specific transition (e.g. HIGH to LOW).
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The script is written in Python 2 and uses the `RPi.GPIO` library as both are
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installed by default on most distributions so should just work. Please note that
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by default the script should be started as root to gain access to the GPIO port.
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To implement a simple power-off button, install the script in `/usr/local/sbin`,
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connect an NC switch (i.e. one that connects when pressed) between pin 39 (GND)
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and pin 40 of the Raspberry Pi and add:
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~~~
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if [ -x /usr/local/sbin/gpio_trigger.py ]; then
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/usr/local/sbin/gpio_trigger.py -D -H 5000 poweroff
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fi
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~~~
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to the file `/etc/rc.local`. This will start the script in the background (`-D`)
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to wait for pin 40 (default pin) to be connected to ground for 5000ms (`-H`) and
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then run the command `poweroff` to shutdown the Raspberry Pi.
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Please refer to the output of `gpio_trigger.py -h` for the options supported and
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defaults used when no option is specified.
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<a name=services>Systemd services</a>
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-------------------------------------
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The repository contains a number of `.service` files, which are systemd service
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descriptions to control specific on-board features of the Raspberry Pi (e.g. to
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disable unused ports). Their purpose should be pretty clear from their name (and
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comments they contain). The rationale of the initial scripts is covered in this
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[blog post](https://frederik.lindenaar.nl/2018/05/11/raspberry-pi-power-saving-disable-hdmi-port-and-others-the-systemd-way.html).
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In general, to install these copy them to the directory `/etc/systemd/system/`
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To manually disable the port, 'start' the 'service' with:
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~~~
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service <<filename without .service>> start
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~~~
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To manually enable the port again, 'stop' the 'service' with:
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~~~
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service <<filename without .service>> stop
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~~~
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To enable starting during system boot (to disable the port) run:
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~~~
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systemctl enable service <<filename without .service>>
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~~~
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To disable starting during system boot (to no longer disable the port) run:
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~~~
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systemctl disable service <<filename without .service>>
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~~~
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<a name="license">License</a>
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-----------------------------
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These scripts, documentation & configration examples are free software: you can
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redistribute and/or modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation, either version 3 of the License,
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or (at your option) any later version.
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This script, documenatation and configuration examples are distributed in the
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hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
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warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, download it from <http://www.gnu.org/licenses/>. |