Changes between Version 2 and Version 3 of mycroft_mark-2_sound

Timestamp:

05/01/20 17:37:04 (5 years ago)

Author:

admin

Comment:

--

mycroft_mark-2_sound

@@ -1 +1 @@
 === Adafruit Volume control ===
-I am controlling the volume of the MAX9744 using the CircuitPython Libraries (see [https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi] ).
+
+UPDATE: Based on a posting of user j1nx on the mycroft forum (thanks a lot!) the better way to control the initial value of the Adafruit using i2cset and an udev-rule
+==== Enable I2C ====
+I2C is not enabled by default so run and enable I2C in the Interfacing Options
+==== Volume control with i2cset (preferred) ====
+Install the i2c-tools:
+* sudo apt-get install i2c-tools
+The command to set the volume (30) is:
+* i2cset -y 1 0x4b 30
+Create the udev-rule:
+* sudo nano /etc/udev/rules.d/10-i2c-sound.rules
+with the content:
+{{{
+SUBSYSTEM=="i2c", ATTR{name}=="bcm2835 I2C adapter", RUN+="/usr/sbin/i2cset -y 1 0x4b 30"
+}}}
+This blindly sets the volume as soon as the i2c adapter is seen by udev.
+===== How to find the value for the udev rule =====
+Use the command:
+* udevadm info -a -p /sys/bus/i2c/devices/i2c-1
+to get the values for SUBSYSTEM and ATTR
+==== Volume control with the Adafruit python library (alternative) ====
+Control the volume of the MAX9744 using the CircuitPython Libraries (see [https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi] ).
 The things that I had to do: 
-==== Install the library ====
+===== Install the library =====
 while in (.venv)
 * pip3 install RPI.GPIO
 * pip3 install adafruit-blinka
 * pip3 install adafruit-circuitpython-max9744
-==== Enable I2C ===
-I2C is not enabled by default so run and enable I2C in the Interfacing Options
-==== Python script ====
+===== Python script =====
 Use this script to set the initial volume to about the half (the range is 0 to 63). Create ~/bin/ada_volume.py with the following content
 * nano ~/bin/ada_volume.py
@@ -20 +39 @@
 amp.volume = 30
 }}}
-==== Start using systemd ====
+===== Start using systemd =====
 Place a service file in the user directory:
 * nano ~/.config/systemd/user/myadavolume.service