Integrate keypads and gamepads into your next project
In Control
The Python evdev library offers a simple way to connect input devices, even if you don't know the key bindings.
Keypads and gamepads can be good solutions for projects that have requirements for simplicity, small form factor, or more rugged operation. Companies like Sony (PS2/PS3) and Logitech, and even makers of generic clones, offer a number of keypads and gamepads for USB wired or wireless products (Figure 1).
Although the Python Pygame library offers a generic keyboard and joystick interface, I found the python-evdev library to be a little simpler and more straightforward.
python-evdev
The python-evdev library [1] provides bindings to the generic input event interface in Linux. The evdev interface passes events generated in the kernel, typically located in /dev/input/
.
To install python-evdev on a Debian-compatible operating system, enter:
sudo apt-get install python-evdev
Not all keypad and gamepad buttons are mapped consistently, so a simple test program is needed to find the keycodes (Listing 1) [2]. For most small systems, the controller's USB connection will be on /dev/input/event0
; on larger systems, event1
or event2
might be the input device. When a key is pressed, the test program outputs the time, keycode, and an alias for the key binding (Listing 2).
Listing 1
keys_evdev.py
Listing 2
Test Program Output
At a minimum, most keypads or gamepads will have the buttons: A, B, X, Y, Start, Select, Left Shoulder, and Right Shoulder. The code in Listing 3 captures these buttons.
Listing 3
gamepad_evdev.py
Summary
With the sample code provided here, you have a starting point for your next kiosk, robotics, or game project; for example, my daughter and I used the evdev interface with a Raspberry Pi to control a two-axis crane (Figure 2).
Infos
- python-evdev: http://python-evdev.readthedocs.io/en/latest/#
- Listings for this article: ftp://ftp.linux-magazine.com/pub/listings/linux-magazine.com/207
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.
-
DebConf24 to be Held in South Korea
Busan will be the location of the latest DebConf running July 28 through August 4