rpi-volume-control

Raspberry Pi volume control using rotary encoder KY040 and ZeroSeg 7 segment display

Hardware:

ZeroSeg 8 character 7 segment display
KY040 rotary encoder with push button function

Installation

1. Update dependencies

Open terminal

sudo apt-get update && apt-get upgrade

2. Setup ZeroSeg as descriped in the manual:

https://cdn.shopify.com/s/files/1/0176/3274/files/ZeroSeg_User_Guide_1.2.pdf

3. Preparing GPIO connection

To use the left GPIO pins which are unfortunately not accessible because ZeroSeg covers all 40 pins you have to different options.

3.1 Connect the used GPIO pins manually using the official pinout from ZeroSeg manual

Name	Description	Physical Pin	RPi Function
DIN	Data In 19	GPIO 10 (MOSI)
CS	Chip Select	24 GPIO 8 (SPI CE0)
CLK	Clock	23 GPIO	11 (SPI CLK)
SW1	Left Switch/Button	11	GPIO 17
SW2	Right Switch/Button	37	GPIO 26

Power supply:

The manual of ZeroSeg gives the following hint:

Power and GND lines have not been documented, however it's worth mentioning that the MAX7219CNG chip uses the 5V line, whilst the switches use 3.3V

For this I connected all of the 40 GPIO pins with male-female wires and simply did some trial and error to check which pins are used for power supply. The result is the following:

First 2 pins of the ZeroSeg are 3V and 5V

GND pin is the pin under the the second 5V pin

Schematic:

Pin	Pin	Description
3V	5V	<== VCC
IO2	5V
IO3	GND	<== GND (choose any if already in use)
IO4	IO14
...	...

Attention

You have to be careful when you connect the pins to the RPi. Do not miscalculate while counting the pins. Do not connect wrong pins, this could damage your RPi seriously. I am not responsible for any damage caused by wrong wiring or use of this tutorial.

OR

3.2 Easy but needs additional hardware:

Get a GPIO exander or multiplexer, google search delivers lots of results.

4. Check audio card

If you use want to use onboard audio enter:

amixer -c 0 controls

If you want to use an external usb sound card enter:

amixer -c 1 controls

Should output results like this:

numid=3,iface=MIXER,name='PCM Playback Switch' numid=4,iface=MIXER,name='PCM Playback Volume' <== Script default, change if necessary numid=2,iface=PCM,name='Capture Channel Map' numid=1,iface=PCM,name='Playback Channel Map'

Note the device descriped with "Playback Volume", here numid = 4

5. Clone and config

git clone https://github.com/Hotwheels93/rpi-volume-control cd rpi-volume-control

Edit volumectl.py:

To set the right sound card change the lines 25, 41 and 76 to with your card number and id:

sudo nano volumectl.py

Example: ['amixer','q', '-c', '1', 'cset', 'numid=4', str(volume)] (default)

Run:

python volumectl.py

6. Autostart (Additional)

To enable autostart open terminal and type

crontab -e

@reboot sudo python /home/pi/rpi-volume-control/volumectl.py