Cattmate

A WiFi enabled physical volume knob for Chromecasts via a mash up of Griffin's no longer made USB device the PowerMate and the awesome python Chromecast controlling library catt using the equally awesome powermate python library. You can optionally show the volume on a screen.

Here's the current demo in an animated gif. Behind the PowerMate is a Chromebook running the Google Home app. When the Cattmate sets the volume you can kinda make out Google Home reflect the volume change as well:

Status

This is my first real Python project! That means while the code is super stable (my desktop version has an uptime of weeks now), I'm guessing not everything follows the Pythonic way just so.

Hardware

• Raspbery Pi - I used a Raspberry Pi Model 3B Rev 1.2
• PowerMate - Hopefully you can find one used on eBay if you don't already have one
• 0.96" SSD1336 OLED Screen (optional) - I use these from MakerFocus
• Chromecast - any sort will do, original, audio or ultra

If the PowerMate is too escoteric, consider checking out cattrotar! Cattrotar is another Chromecast volume control project, but it uses a cheap, comodity Rotary Encoder instead (<$2/ea).

Use

Cattmate supports:

• Increase volume - rotate clockwise
• Decrease volume - rotate counter-clockwise
• Mute - push down - the light will strobe to denote muted status
• Unmute - push down again
• Pause - push down and hold 1+ second
• Play - push down and hold 1+ second again
• Fast Forward - push down and rotate clockwise
• Rewind - push down and rotate counter-clockwise

Install

These steps assume you have your Pi set up with Raspbian, that it's booted up, connected to the same WiFi as your Chromecast. If your Chromecast is on a different network, but you can get to it by IP, the config supports IPs instead of Chromecast names. It also assumes you're using the pi default user with a home directory of /home/pi and that you have both pip3 and optionally virtualenv installed:

1. Clone this repo and cd into it: git clone https://github.com/Ths2-9Y-LqJt6/cattmate.git /home/pi/cattmate; cd /home/pi/cattmate
2. Create your own virtualenv and activate it python3 -m venv venv;. venv/bin/activate (optional)
3. Install all the python prerequisites with pip3 install -r requirements.txt
4. Create your own config file cp config.dist.py config.py and edit config.py with the names or IPs of the chromecasts you want to use (only first one supported right now ;) and whether you want to use an external I2C screen or not
5. Copy the systemd file into place, reload systemd, start and enable it:

   sudo cp cattmate.service /etc/systemd/system/
   sudo systemctl daemon-reload
   sudo systemctl enable cattmate
   sudo systemctl start cattmate

6. Add the udev rule with sudo cp 60-powermate.rules /etc/udev/rules.d/ and plug your powermate into an open USB port.

You should be good to go! The system is very resilient in that you can not have screen plugged in when you start and the plug it in and systemd will notice and start things up. Same for the powermatte - you can unplug and plug and unplug all day and it satisfyingly just works!

Troubleshooting

You can debug the system in syslog with sudo tail -f /var/log/syslog. I try to do a lot of testing and explicit have except errors that explicitly tell you what went wrong and how to fix it.

Note that on slower devices, like the Pi 1 that I tested on, startup can take >60sec, so be patient ;)

If all else fails, open an issue and I'l try and help ya!

Releases

• 14 Jan 2020 v0.5 - Rewrite readme, add both cattmate.service and 60-powermate.rules for systemd and udev rules respectively.
• 16 Dec 2019 v0.13 - Complete refactor to use native python driver per #8 and add pause, ff & rrwnd per #10
• 13 Dec 2019 v0.12 - Add MIN/MAX alerts per #2, fix #1
• 10 Dec 2019 v0.11 - refactor ssd1306 lib to Csd1306 class, simplify calls to same, refactor for cleaner code
• 10 Dec 2019 v0.10 - first decently functional code, known issue in #1 though.