Arduino IO Expansion Shield - Waveshare

Features : - 3-pin 4-pin sensor interfaces, supports connecting sensors directly without complicate custom connection - XBee module connector - WIFI-LPT100 wireless module connector 1. XBee module connector 2. IIC interface 3. SPI interface 4. 3-pin sensor interface VCC : power positive GND : ground D : digital pin, correspond to the Arduino board 5. WIFI-LPT100 connector 6. 4-pin sensor interface VCC : power positive GND : ground A : analog pin, correspond to the Arduino board D : digital pin, correspond to the Arduino board 7. VCC configuration : for selecting sensor interfaces power voltage 8. Debugging/Communication selection jumper when connecting TXD and TX, RXD and RX respectively, the Arduino board may debug/config the 9 XBee module or WIFI-LPT100 through serial port when connecting TXD and RX, RXD and TX respectively, the Arduino board may communicate with the XBee module or WIFI-LPT100 through serial port 9. Power indicator 10. WIFI-LPT100 state indicator 11. XBee module state indicator 12. WIFI-LPT100 RELOAD button : for restoring to factory setting 14. XBee module and WIFI-LPT100 RESET button 15. XBee module EASYLINK button Sources: https://www.waveshare.com/io-expansion-shield.htm