OK, we have to be truthful with this one: it is a spy tool. We do not recommend building or using it and w do not take any responsibility if you do so. So what is this? It is called KeySweeper and is Arduino-based device that is capable of capturing every single keystroke typed on Microsoft wireless keyboards. It will even send you SMS when someone starts typing and upload the logs to online server and also keep them stored on the device. Luckily it is not for sale but those of you who want to have it can build it, it will cost you from $10-$80, depending on desired functionality. Scary ,isn’t it? From now on,you will not trust nay charger looking gadget plugged into a wall.