Knob - Volume - mouse scroll hack

[Wiredcharlie]

Here is a shell script that takes input from the mouse scroll wheel to change the volume of the named local player. I wrote it with a view to hacking a Poundland mouse plus rotary encoder to put a real volume knob on my LMS / Squeezebox computer. I would welcome any comments or suggestions.

#!/bin/bash

#use command - xinput - to find id of mouse who's scroll wheel you want to use
mouseID=10 
player='Dining Room'
IP="127.0.0.1 9090"




  #Need to convert player name to mac address
  #find number of players
 
  nplayers=$(echo "player count ?" | nc -q1 $IP | tail -c 2 )


  n=0
	#loop through players to determine mac address of player

	while [ $n -lt $nplayers ]
	do
		pmac=$(echo "player id $n ?" | nc -q1 $IP | tail -c 28 | sed -r 's/%3A/:/g' )
		pname=$(echo "player name $n ?" | nc -q1 $IP | cut -c 15- | sed -r 's/%20/ /g')
			if [ "$pname" = "$player" ]; then
				playerID=$pmac
				echo
				echo "$pname"   "$pmac"
			fi
		n=$(($n + 1))
	done

echo
OldScroll=$(xinput --query-state $mouseID | grep 'valuator\[2\]\=' | cut -c 14-)
echo "Initial wheel position: $OldScroll"
playerVOL=$(printf "$playerID mixer volume ?\nexit\n" | nc $IP | tail -c 3 | tr -dc '0-9')
echo "Initial Volume: $playerVOL"
echo

# Infinite loop checks to see if mouse scroll wheel has turned and in which direction - Ctrl C to quit

while :
do

scroll=$(xinput --query-state $mouseID | grep 'valuator\[2\]\=' | cut -c 14-)

if [ $OldScroll -gt $scroll ]; then
	playerVOL=$(printf "$playerID mixer volume ?\nexit\n" | nc $IP | tail -c 3 | tr -dc '0-9')
	setVOL=`expr $playerVOL + 5`
	printf "$playerID mixer volume $setVOL\nexit\n" | nc $IP
fi

if [ $scroll -gt $OldScroll ]; then
	playerVOL=$(printf "$playerID mixer volume ?\nexit\n" | nc $IP | tail -c 3 | tr -dc '0-9')
	setVOL=`expr $playerVOL - 5`
	printf  "$playerID mixer volume $setVOL\nexit\n" | nc $IP
fi
  
OldScroll=$scroll  
sleep 0.2

done

[Roland0]

Here is a shell script that takes input from the mouse scroll wheel to change the volume of the named local player. I wrote it with a view to hacking a Poundland mouse plus rotary encoder to put a real volume knob on my LMS / Squeezebox computer. I would welcome any comments or suggestions.

This might be of interest.

[Wiredcharlie]

This might be of interest.

From what I can see that is button/keypress only. The point (for me) is to have the rotation of a traditional volume knob that properly interfaces with the LMS volume setting. Most of the Human Interface Device implementations I could find used a programmed microcontroller to provide a USB interface. I figured that looked like hard work when a mouse scroll wheel already does that! Then I stumbled across this https://19max63.wordpress.com/2016/0...-knob-for-sdr/
where someone had connected a standard rotary encoder to a mouse PCB.

My server is a headless MiniATX box which also provides a local player output, so I figured if I added a volume knob on the front it would look like a piece of HiFi!

Tony

[Roland0]

From what I can see that is button/keypress only.

It uses python-evdev, which is a interface to evdev and reports all device events (X uses evdev as well btw). Haven't tested it with inputexec, but this works:

#!/usr/bin/env python3
import evdev
device = evdev.InputDevice('/dev/input/event10')
print(device)
for event in device.read_loop():
	if event.code == evdev.ecodes.REL_WHEEL:
		print("Event: {} value: {}".format( evdev.categorize(event), event.value))

device /dev/input/event10, name "Logitech USB Laser Mouse", phys "usb-0000:00:1d.0-1.6/input0"
Event: relative axis event at 1574017671.107975, REL_WHEEL  value: -1
Event: relative axis event at 1574017672.227968, REL_WHEEL  value: 1

so you could just add a line to send something (e.g. with requests) to LMS in that if clause

Anyway, I've switched to triggerhappy in the meantime, which will also work with the wheel:

$  cat ../THD.conf
REL_WHEEL	1	echo "wheel up" >> /tmp/thd.log
REL_WHEEL	-1	echo "wheel down" >> /tmp/thd.log

./thd --triggers ../THD.conf /dev/input/event10
Executing trigger action: echo "wheel down" >> /tmp/thd.log
Executing trigger action: echo "wheel up" >> /tmp/thd.log