Using a special firmware image provided by Nordic Semiconductors and the open source network analysis tool Wireshark, the Bluefruit LE Sniffer can be used as a low cost Bluetooth Low Energy sniffer. Introducing the Adafruit Bluefruit LE Sniffer
Ubertooth
Ubertooth – Open-Source Bluetooth Sniffing Homepage
Libraries
Bleno
A Node.js module for implementing BLE (Bluetooth Low Energy) peripherals Npm Page