Wi-PWN
ESP8266 firmware for performing deauthentication attacks
...A deauthentication attack is often confused with Wi-Fi jamming, as they both block users from accessing Wi-Fi networks. The 802.11 Wi-Fi protocol contains a so-called deauthentication frame. It is used to disconnect clients safely from a wireless network. Because these management packets are unencrypted, you just need the MAC to address of the Wi-Fi router and of the client device which you want to disconnect from the network. You don’t need to be in the network or know the password, it’s enough to be in its range. With the 802.11w-2009 updated standards, management frames are encrypted by default.