1.on-board STC15L204EA single-chip microcomputer, the single chip microcomputer as 3.3 V power supply
2.on-board for NRF24L01 wireless module 2 * 4 parent interface
3.on-board UART interface, used to implement the serial communication
4.on-board 5 V to 3.3 V AMS1117-3.3 chip
5.all the I/O derivation, and mark the I/O name
6.PCB size: 39 (mm) x26 (mm)