Quantity   Component name
1 × Raspberry PiZero to bring from your home
1 × I2C Character display (8 x 2) to display "hello" or some messages to the user [ http://akizukidenshi.com/download/ds/xiamen/AQM0802.pdf ]
1 × ESP-WROOM-02 ( ESP8266 ) to control I2C Character display and communicate with PiZero / store and recover message [ http://akizukidenshi.com/download/ds/espressifsystems/0C-ESP8266__WROOM_WiFi_Module_Datasheet__EN_v0.4.pdf ]
1 × Voltage converter (5V to 3.3V) using three terminal regulator such as those used in https://upverter.com/7of9/176ba6a2f9665138/SNS-MQ135_160209/ to supply power to ESP8266
1 × USB Hub