DIY Bluetooth MicroPCI Express From Cheap £1 USB Adapter. : 7 Steps - Instructables
DIY Wireless Serial Adapter Speaks (True) RS-232 | Hackaday
My parents found this weird cable in their house. It's micro usb that splits out into two other cables, one with a regular usb end, the other with a unknown plastic box
Miniature WiFi (802.11b/g/n) Module: For Raspberry Pi and more : ID 814 : $11.95 : Adafruit Industries, Unique & fun DIY electronics and kits