Powercycle JS

A Gnome/libadwaita/gtk4 app that allows you to control your indoor bike's smart trainer's power with a very simple interface and an ANT+ USB stick.

Leverages the gjs runtime for the GUI.

Screenshot

Setup

Built with Node 20, but may work with other versions.

sudo pacman -S gjs gtk4 libadwaita libusb libgusb
pnpm install

# finding your ANT+ device ID requires uncommenting "await fes.scan();" in event.ts.
# sorry this is awkward right now, but i hope to improve it later, if i can find the time
export POWERCYCLE_ANT_CHANNEL_ID=0
export POWERCYCLE_ANT_DEVICE_ID=5555

pnpm run start

You also need to set up the udev rules for your ant+ USB stick:

Edit /etc/udev/rules.d/99-ant.rules

SUBSYSTEM=="usb", ATTR{idVendor}=="0fcf", ATTR{idProduct}=="1008", MODE="0666"
SUBSYSTEM=="usb", ATTR{idVendor}=="0fcf", ATTR{idProduct}=="1009", MODE="0666"

Then run:

sudo udevadm control --reload-rules
sudo udevadm trigger

You also may need to be a part of the dialout group (unverified).

Reference

• https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/style-classes.html
• /usr/share/icons/Adwaita/symbolic/ for icons

Comments

• This application is unpolished, unfinished, and may be unstable. Despite this fact, I use it regularly and find it to be good enough for daily use.
• I wrote this as an example of leveraging gjs for libadwaita/gtk4 and it's mostly for fun/personal gain
• If you make improvements, please contribute them back in accordance with the license
• This application consists of two components:
  • GUI: A libadwaita app that has a very minimal interface inspired by a commonly used app for smart trainers.
  • Server: A headless Node program that connects to the ANT+ USB stick and writes device data to a file.
  • Why does it have two components? The gjs runtime is limited and doesn't seem to support the ANT+ libusb interactions that are required. We have to use Node.
• Instead of using websockets for IPC, the GUI watches for changes to files called .control, .stats, and .quit, which are written to by the server.
• I need to refactor and clean up lots of this code, don't judge me, this is something I do in my limited spare time
• Doesn't support heart rate yet, but I'd like to do that soon

Troubleshooting

If you run into problems, it might be caused by a few things:

• Put your ANT+ USB stick closer to your trainer with a USB extension cord
• Unplug your ANT+ USB stick, kill this application (server and ui), plug in the stick, then restart the application
• Make sure you followed the udev rules steps above, and make sure you have permissions to talk to the device (restart/full log out may be necessary)