Hidden bicycle media Play/Pause button (for 22.2mm handlebar)

I always wanted to make by bicycle smart, but unfortunately all the gadgets I could think of would only add clutter the handlebar and look not very nice. Therefore the idea of trying to hide it inside the handlebar.

This device combines following components:

• Seeed Studio XIAO nRF52840
• A generic 602030 300mAh battery
• A generic D2FC-F-7N microswitch

Printing:

• I used ABS, so some dimensions might need tweaked when printed in other materials.
• I recommend against PLA or similar, since handlebar might heat quite a lot under the sun.

This device can work as a:

• Play/Pause button, camera shutter button, or any kind of keyboard sequence (code)
• Openhaystack beacon, (ab)using Apple FindMy infrastrcture (use this firmware with target xiao-ble)
• Both? There are some issues preventing it from being easily done, but I'll try to make it work in the future.

Battery life: Theoretically speaking, this should be able to work from the battery for over a year without charging. In practice, I still need to make sure both firmware and hardware are configured to do that without an issue.

Assembly:

• Solder one switch pin to the board ground pin, another to the D1 pin (or any other GPIO), watch out for the switch connection diagram (basically connect either C/NO, or C/NC)
• Solder battery to the board (try to not short it out)
• Add a generous amount of hot glue (for the board and the switch but not around the battery), VHB (to secure the battery) and capton tape (around everything to insulate from moisture)
• Flash the firmware

Flashing the arduino firmware.

• See Getting started for the board and configuring Arduino environment
• Flash the following sketch: https://github.com/derlaft/blebikeremote/blob/main/blehid_remote.ino
• Power-cycle the device and press the button once. Now you should be able to pair your phone. I tested Android only, but it should work with other devices.
• Now you should be ready to go!