It is a wifi remote controller built with arduino uno and HC05 wifi module. It is powered by 2 pieces of lipo batteries. Construction Pin Assignment Pin Function remarks PB0 key drive SW20, SW30 PB1 key drive SW21, SW31 PB2 key drive SW22, SW32 PB3 LED PB5 LED UNO PD0 RX UART PD1 TX UART PD2 key sense SW2, SW20, SW21, SW22 PD3 key sense SW3, SW30, SW31, SW32 AREF ADC battery PB1 ^ PB0 < PD2 > PB2