rpi-button-box

Core program for a Raspberry Pi button box controller that uses the gpiozero Python library. This repo is a companion to my blog post about repurposing external HDD cases into button boxes. If you have any questions or want to share your opinions, use the Discussions option. If you have issues with the program, then open an issue.

Disclaimer

This is free and has no warranty whatsoever. Use it at your own risk. Misconfigured pins might damage your board.

Preview

Wiring

Requirements

• Raspberry Pi
  • 40 GPIO pins version (but you can easily adapt to any revision)
• Python3
  • gpiozero, rpi.gpio, (and other standard Python libraries)

Installation

The button box controller was developed for the Lite version of the Raspberry Pi OS but it should work with other similar systems for single board computers (e.g., Armbian).

The following instructions assume you're logged in with the pi user with sudo permission. (This is not a requirement but if different, make sure to change file permissions accordingly. This applies to systemd service file and logrotate/button-box config as well.)

1. Use apt to install required programs

sudo apt update
sudo apt install git python3 python3-pip

2. Clone the rpi-button-box repo in /opt

cd /opt
sudo git clone https://github.com/cgomesu/rpi-button-box.git
sudo chown -R pi rpi-button-box

3. Install Python libraries from requirements.txt

pip3 install -r /opt/rpi-button-box/requirements.txt

4. Test button-box.py

cd /opt/rpi-button-box
./button-box.py -h

5. (Optional.) Allow logrotate (enabled by default) to manage the button-box.log log files:

sudo cp /opt/rpi-button-box/logrotate.d/button-box /etc/logrotate.d/

Usage

./button-box.py -h

usage: button-box.py [-h] [--buzzer BUZZER] [--cmd {Popen,run}]
                     [--g1_pressed G1_PRESSED] [--g1_released G1_RELEASED]
                     [--s1_held S1_HELD] [--s1_released S1_RELEASED] [-i] [-d]

RPi button box controller. Repo: https://github.com/cgomesu/rpi-button-box

optional arguments:
  -h, --help            show this help message and exit
  --buzzer BUZZER       If installed, the buzzer's GPIO number.
  --cmd {Popen,run}     Popen: run external scripts in a NON-BLOCKING fashion.
                        run: run external scripts in a BLOCKING fashion.
                        Default=run
  --g1_pressed G1_PRESSED
                        /path/to/script to run when G1 is pressed. The
                        --btn_pressed arg is available to other PUSH buttons
                        as well.
  --g1_released G1_RELEASED
                        /path/to/script to run when G1 is released. The
                        --btn_released arg is available to other PUSH buttons
                        as well.
  --s1_held S1_HELD     /path/to/script to run when S1 is held. The
                        --btn_held arg is available to other SWITCHES as well.
  --s1_released S1_RELEASED
                        /path/to/script to run when S1 is released. The
                        --btn_released arg is available to other SWITCHES as
                        well.
  -i, --info            Show the board information.
  -d, --debug           Print additional messages to the terminal.

As mentioned, there are hidden arguments for passing external scripts to be executed upon a button event, such as pressing G2, or releasing S3. More specifically, in addition to --g1_* and --s1_* args shown in the help output, the program accepts args for any of the other seven buttons, as follows

• script for pressed and released events: the push buttons --g1_*, --b1_*, --r1_*, --g2_*, --b2_*, and --r2_*,
• script for held and released events: the switches --s1_*, --s2_*, and --s3_*.

The script generates a button-box.log log file to keep track of controller-related events.

Examples

• Output info about the board

./button-box.py -i

• Run the controller in debug mode (prints more messages to the terminal) and enable the buzzer (GPIO4)

./button-box.py -d --buzzer 4

• Run the controller with a buzzer and execute /opt/rpi-button-box/scripts/template.sh whenever the push button R2 is pressed:

./button-box.py --buzzer 4 \
--r2_pressed '/opt/rpi-button-box/scripts/template.sh'

• Same as before, but don't wait for the external script to finish running (non-blocking command execution):

./button-box.py --buzzer 4 --cmd Popen \
--r2_pressed '/opt/rpi-button-box/scripts/template.sh'

Run the controller as a service

If you're using options different than the default values, first edit the systemd/button-box.service file to include those options into the ExecStart= command execution. (Reminder: If you've installed Python3 libraries with a user different than pi and the rpi-button-box dir is owned by another user, you'll have to edit the systemd/button-box.service file to reflect such changes. Otherwise, you will run into errors related to permission.) Then, run button-box.py as a service, as follows:

1. Copy the systemd/button-box.service file to your systemd directory

sudo cp /opt/rpi-button-box/systemd/button-box.service /lib/systemd/system/

2. Enable the service and start it

sudo systemctl enable button-box.service
sudo systemctl start button-box.service

3. Check the service status to make sure it's running without issues

systemctl status button-box.service

Bash script template

I've included a template for bash scripts on scripts/template.sh that anyone can use to create their customized set of commands to run upon a button event. Just copy the template, rename it, edit it according to your needs, and when running the button-box.py controller, add the full path to the new script to one (or more) of the --btn_* arguments. For example:

./button-box.py --buzzer 4 \
--g1_pressed '/opt/rpi-button-box/scripts/notification.sh' \
--b1_pressed '/opt/rpi-button-box/scripts/switch_cameras.sh' \
--r1_pressed '/opt/rpi-button-box/scripts/lights_toggle.sh' \
--g2_pressed '/opt/rpi-button-box/scripts/test_connectivity.sh' \
--b2_pressed '/opt/rpi-button-box/scripts/shutdown.sh' \
--r2_pressed '/opt/rpi-button-box/scripts/reboot.sh' \
--s2_held '/opt/rpi-button-box/scripts/alarm_on.sh' \
--s2_released '/opt/rpi-button-box/scripts/alarm_off.sh' \
--s3_held '/opt/rpi-button-box/scripts/emergency.sh'