This is the HC-21 an embedded Wi-Fi UART module built IEEE802.11 wireless network protocol stacks and TCP/IP protocol to achieve conversation between serial data to wireless network communication. The HC21 can be connected via wireless to wireless without any support
Wiring the PCF8574AP 8bit Bidirectional IO Expander Driven i2C Communication Bus / SPI
This is the PCF8574AP consists of an 8-bit quasi-bidirectional port and an i2C Serial Bus Interface. The PCF8574AP has a low current consumption and includes latched output with HIGH consumption and include latched output with high current drive capability for