ESP8266 (ESP01, ESP01-S)
De ESP8266 is een goedkope microprocessor met Wi-Fi mogelijkheid en een volledige TCP/IP stack. De ESP8266 is ontwikkeld en wordt geproduceerd door de Chinese fabrikant Espressif Systems uit Shanghai.
ESP8266 Pin Configuration
| Pin Number | Pin Name | Alternate Name | Normally used for | Alternate purpose |
| 1 | Ground | – | Connected to the ground of the circuit | – |
| 2 | TX | GPIO – 1 | Connected to Rx pin of programmer/uC to upload program | Can act as a General purpose Input/output pin when not used as TX |
| 3 | GPIO-2 | – | General purpose Input/output pin | – |
| 4 | CH_EN | – | Chip Enable – Active high | – |
| 5 | GPIO – 0 | Flash | General purpose Input/output pin | Takes module into serial programming when held low during start up |
| 6 | Reset | – | Resets the module | – |
| 7 | RX | GPIO – 3 | General purpose Input/output pin | Can act as a General purpose Input/output pin when not used as RX |
| 8 | Vcc | – | Connect to +3.3V only |