keychron_qmk_firmware/keyboards/converter/usb_usb/ble/readme.md

QMK BLE Adapter

A small device that reads USB keyboard input and passes it on over Bluetooth LE HID.

Hardware

The hardware is relatively easy to assemble. Just follow the schematic and don't forget to cut the VBUS jumper.

Schematic:

Part list:

• Adafruit Feather 32u4 Bluefruit LE
• USB Host Mini
• Pololu 5V Step-Up Voltage Regulator U3V12F5
• Lithium Ion Battery - 3.7v 2000mAh
• Some sort of switch to be able to turn it off