samyk/keysweeper
KeySweeper is a stealthy Arduino-based device, camouflaged as a functioning USB wall charger, that wirelessly and passively sniffs, decrypts, logs and reports back (over GSM) all keystrokes from any Microsoft wireless keyboard in the vicinity.
License & maintenance
No license stated: by default nobody may reuse the code. Ask the authors before using it in a product.
Last code push 9 years ago.