Access joysticks/game controllers from Python in Linux via the joystick driver. See https://discourse.panda3d.org/t/game-controllers-on-linux-without-pygame/14128

js_linux.py

# Released by rdb under the Unlicense (unlicense.org)
# Based on information from:
# https://www.kernel.org/doc/Documentation/input/joystick-api.txt

import os, struct, array
from fcntl import ioctl

# Iterate over the joystick devices.
print('Available devices:')

for fn in os.listdir('/dev/input'):
    if fn.startswith('js'):
        print('  /dev/input/%s' % (fn))

# We'll store the states here.
axis_states = {}
button_states = {}

# These constants were borrowed from linux/input.h
axis_names = {
    0x00 : 'x',
    0x01 : 'y',
    0x02 : 'z',
    0x03 : 'rx',
    0x04 : 'ry',
    0x05 : 'rz',
    0x06 : 'throttle',
    0x07 : 'rudder',
    0x08 : 'wheel',
    0x09 : 'gas',
    0x0a : 'brake',
    0x10 : 'hat0x',
    0x11 : 'hat0y',
    0x12 : 'hat1x',
    0x13 : 'hat1y',
    0x14 : 'hat2x',
    0x15 : 'hat2y',
    0x16 : 'hat3x',
    0x17 : 'hat3y',
    0x18 : 'pressure',
    0x19 : 'distance',
    0x1a : 'tilt_x',
    0x1b : 'tilt_y',
    0x1c : 'tool_width',
    0x20 : 'volume',
    0x28 : 'misc',
}

button_names = {
    0x120 : 'trigger',
    0x121 : 'thumb',
    0x122 : 'thumb2',
    0x123 : 'top',
    0x124 : 'top2',
    0x125 : 'pinkie',
    0x126 : 'base',
    0x127 : 'base2',
    0x128 : 'base3',
    0x129 : 'base4',
    0x12a : 'base5',
    0x12b : 'base6',
    0x12f : 'dead',
    0x130 : 'a',
    0x131 : 'b',
    0x132 : 'c',
    0x133 : 'x',
    0x134 : 'y',
    0x135 : 'z',
    0x136 : 'tl',
    0x137 : 'tr',
    0x138 : 'tl2',
    0x139 : 'tr2',
    0x13a : 'select',
    0x13b : 'start',
    0x13c : 'mode',
    0x13d : 'thumbl',
    0x13e : 'thumbr',

    0x220 : 'dpad_up',
    0x221 : 'dpad_down',
    0x222 : 'dpad_left',
    0x223 : 'dpad_right',

    # XBox 360 controller uses these codes.
    0x2c0 : 'dpad_left',
    0x2c1 : 'dpad_right',
    0x2c2 : 'dpad_up',
    0x2c3 : 'dpad_down',
}

axis_map = []
button_map = []

# Open the joystick device.
fn = '/dev/input/js0'
print('Opening %s...' % fn)
jsdev = open(fn, 'rb')

# Get the device name.
#buf = bytearray(63)
buf = array.array('B', [0] * 64)
ioctl(jsdev, 0x80006a13 + (0x10000 * len(buf)), buf) # JSIOCGNAME(len)
js_name = buf.tobytes().rstrip(b'\x00').decode('utf-8')
print('Device name: %s' % js_name)

# Get number of axes and buttons.
buf = array.array('B', [0])
ioctl(jsdev, 0x80016a11, buf) # JSIOCGAXES
num_axes = buf[0]

buf = array.array('B', [0])
ioctl(jsdev, 0x80016a12, buf) # JSIOCGBUTTONS
num_buttons = buf[0]

# Get the axis map.
buf = array.array('B', [0] * 0x40)
ioctl(jsdev, 0x80406a32, buf) # JSIOCGAXMAP

for axis in buf[:num_axes]:
    axis_name = axis_names.get(axis, 'unknown(0x%02x)' % axis)
    axis_map.append(axis_name)
    axis_states[axis_name] = 0.0

# Get the button map.
buf = array.array('H', [0] * 200)
ioctl(jsdev, 0x80406a34, buf) # JSIOCGBTNMAP

for btn in buf[:num_buttons]:
    btn_name = button_names.get(btn, 'unknown(0x%03x)' % btn)
    button_map.append(btn_name)
    button_states[btn_name] = 0

print('%d axes found: %s' % (num_axes, ', '.join(axis_map)))
print('%d buttons found: %s' % (num_buttons, ', '.join(button_map)))

# Main event loop
while True:
    evbuf = jsdev.read(8)
    if evbuf:
        time, value, type, number = struct.unpack('IhBB', evbuf)

        if type & 0x80:
             print("(initial)", end="")

        if type & 0x01:
            button = button_map[number]
            if button:
                button_states[button] = value
                if value:
                    print("%s pressed" % (button))
                else:
                    print("%s released" % (button))

        if type & 0x02:
            axis = axis_map[number]
            if axis:
                fvalue = value / 32767.0
                axis_states[axis] = fvalue
                print("%s: %.3f" % (axis, fvalue))

Sorry, it seems GitHub does not notify me of comments on my own gist.

@kharlashkin: I haven't attempted to use force-feedback features yet, so I cannot advise you on the matter, sorry.

@zdavidmm: When you first connect with open(), the API will give you the current state of all the buttons. You can use this to your advantage by opening the device, reading out all "initial state" events, and then closing it again.

Thanks for your work, but I would like to go thru the
evbuf = jsdev.read(8)
not necessarily to wait in this instruction until joystick has an event , not sure if possible or if I'm correct in my view.
In other words I would like to read the current state and continue not to wait for an event. (Something similar with pygame joystick)
Thanks ,CR

OK I see a response above, I will try,, thanks.

Hi!
I use the script for a rc car, controlled by a ps4 controller. How can I use key combinations?

0x3b - 0x3e are for ps3 sixaxis but im not sure which is which

This code gives me a lot of syntax errors, specifically on the print statements. I'm new to python and Raspberry pi. Is there something I'm doing wrong? I'm using Pi4 and python 3.7.3.

This code gives me a lot of syntax errors, specifically on the print statements. I'm new to python and Raspberry pi. Is there something I'm doing wrong? I'm using Pi4 and python 3.7.3.

@jwells4 I have just updated the gist to use Python 3 print functions instead of Python 2 print statements.

Thanks so much for making the changes! I was actually doing those myself, but it's nice when it's done by someone more familiar with the language than me lol. I'm still getting errors, but not with the prints. Now I'm getting the following output when running the code:

Available devices:
/dev/input/js0
Opening /dev/input/js0...
Traceback (most recent call last):
File "controllerTest.py", line 101, in
buf = array.array('c', ['\0'] * 64)
ValueError: bad typecode (must be b, B, u, h, H, i, I, l, L, q, Q, f or d)

From what I've been able to find online, this is because 'c' is not a valid type as of 3.5? Based on some reading, I replaced the 'c' with 'u' (for unicode) and the code now seems to work. There may be a more-correct or more elegant way of doing this, but I wanted to point it out anyway. Thanks for the response and the code update!

@jwells4 I think that is not correct; I have just updated the code to what I think should be right, though I have not tested it with Python 3 yet.

I just tested it on my setup and it works well. The difference between your update and my noob solution was that the device name now properly displays. Again, thanks so much for updating this. It's been super helpful.

Got this to work on python3 here:

https://gist.github.com/emdeex/97b771b264bebbd1e18dd897404040be

Got this to work on python3 here:

https://gist.github.com/emdeex/97b771b264bebbd1e18dd897404040be

Thanks!

Works right out of the box with an xbox one controller on my raspberry pi. Thanks man. Saved me a headache.

I think the JSIOCGBTNMAP IOCTL call has the wrong magic number.

If I'm reading the kernel source correctly, buf should be 0x200 unsigned shorts ((KEY_MAX - BTN_MISC) + 1), not decimal 200.

Also, len(buf) gives the number of elements in buf (0x200). (buf.buffer_info()[1] * buf.itemsize) returns the size in bytes (0x400).

If both assumptions are correct, the magic number should be 0x84006a34, not 0x80406a34.

Also, "throttle" is misspelled as "trottle".

@d-wiles that really depends on which version of the headers you have; I just tried in CentOS 5 and it's even 0x82006a34. Linux is flexible about this, masking out the size bits:
https://github.com/torvalds/linux/blob/6417f03132a6952cd17ddd8eaddbac92b61b17e0/drivers/input/joydev.c#L578

KEY_MAX also used to have a lower value.

Thank you for your work, but you don't have to wait for this command until there's an event on the joystick
I would like to proceed
evbuf = jsdev.read(8).
I want to look at the camera while controlling the RC car. However, there must be an event for the camera to work.

You can probably make it non-blocking by using the lower-level os.open() instead of open() with the os.O_RDONLY | os.O_NONBLOCK flags.

Another way is to use a thread. It will be woken up when there is data available.

Thank you for your feed pack. But I get an error.
(AttributeError: 'int' object has no attribute 'read')
I'm sorry I'm a Python beginner.

It's not that trivial: the os.open() call is different than built-in open(), it returns a fd, you have to use it with the other functions from the os module, change all the calls to those instead.

Thank you for answer. But I'm a Python beginner, sorry. I'm not sure exactly which part I need to change. Can you give more detailed feedback?

I checked and instead of os.open there may be an easier alternative, by calling this on the file after the open call:

os.set_blocking(jsdev.fileno(), False)

Of course you'll need to deal with the exception you will probably get when calling read() without data being available.

Hi, i want to control servo with a joystick by using a Raspberry Pi How can I take input from the joystick and give it to Servo?
basically controlling th servo through the joystick.