The D1 Mini includes WiFi, but it doesn’t have Bluetooth so this shield allows you to add an HC-05 (or pin-compatible) Bluetooth serial module.
The Bluetooth module uses a serial connection, so the D1 Mini can simply open a serial port using pins D0 and D5 to talk to the module. The shield also brings out pads for RESET and COMMAND jumpers. The RESET jumper links the Bluetooth reset to the D1 Mini reset, so that the Bluetooth module is forced to reset every time the D1 Mini does. The COMMAND jumper forces the HC-05 Bluetooth module into command mode, which can be used by the D1 Mini to send new configuration commands to the module. You can also link this across to one of the digital pins if you like, so that the D1 Mini can put the Bluetooth module into command mode under software control.
PCBs for these haven’t arrived yet. I’ll update this page when they are available.
Source files: github.com/SuperHouse/D1MBLUE