Read raw mouse data on linux

Question

I want to use an optical mouse with the Raspberry PI for indoor positioning for which I want to capture raw mouse data and calculate position from it. This is what I have right now (in Ruby)

File.open("/dev/input/by-id/usb-15d9_USB_OPTICAL_MOUSE-mouse") do |f|
  loop do
    p f.read(16)
  end
end

I can't make sense of the output. It would be of great help if any of you pointed me to a resource explaining how this file is supposed to be interpreted and/or how I can calculate position or displacement from it.

I cannot use xdotool or Xlib because the Raspberry PI won't be running any windowing system.

here is the python based decoder http://stackoverflow.com/questions/4855823/get-mouse-deltas-using-python-in-linux — VivekD, Apr 29 '17 at 18:53
Please read "[ask]" and "[mcve]". We need more information. What does the minimum "output" look like? Asking us to point you to a resource is off-topic. — the Tin Man, Apr 29 '17 at 21:28

score 0 · Answer 1 · answered Apr 30 '17 at 03:14

0

DPI = 1000.0
MOUSE_FILE = ""

# Read mouse device file
File.open(MOUSE_FILE) do |f|
  loop do
    _button, dx, dy =  f.read(3).unpack('Ccc')

    x += dx
    y += dy

    puts "#{x * 2.5 / DPI}, #{y * 2.5 / DPI}"
  end
end

answered Apr 30 '17 at 03:14

prajwaldp

178
1
14

Read raw mouse data on linux

1 Answers1