I. Overview
The ESP8266 eight-way relay development board is equipped with ESP-12F WiFi module and supports DC7-28V/5V power supply. Provide Arduino development environment reference code, suitable for ESP8266 secondary development learning, smart home wireless control and other occasions.
 
II. Features
1. On-board mature and stable ESP-12F WiFi module, large capacity 4M Byte Flash;
2. The power supply mode supports DC7-28V/5V;
3. The onboard WiFi module RST reset button;
4. ESP-12F supports the use of Eclipse/Arduino IDE and other development tools, and provides reference programs under the Arduino development environment;
5. There are 8 5V relays on board, outputting switch signals, suitable for controlling loads whose working voltage is within AC 250V/DC30V;
6. Onboard power indicator and relay indicator.
 
III. Hardware introduction and description:
1. Board size: 148*79.8mm
Weight: 140g
 
Programming port: ESP8266's GND, RX, TX, 5V are respectively connected to the GND, TX, RX, 5V of the external TTL serial port module. IO0 needs to be connected to GND when downloading, and then disconnect the connection between IO0 and GND after the download is complete;
Relay output:
NC: Normally closed, the relay is short-connected with COM before the pull-in, and hangs in the air after pull-in;
COM: public end;
NO: Normally open end, the relay is suspended before being closed, and shorted to COM after being closed
3. Introduction to GPIO port
1	ADC	A/D conversion result. Input voltage range: 0～1V, value range: 0～1024
2	IO2	GPIO2; UART1_TXD
	TXD	UART0_TXD; GPIO1
3	RXD	UART0_RXD; GPIO3
4	GND	GND
5	5V	5V Power
Package Include:
1x DC 5V DC 7-28V ESP8266 WIFI 8 Channel Relay Module ESP-12F Development Board

Package includes:

DC 5V DC 7-28V ESP8266 WIFI 8 Channel Relay Module ESP-12F Development Board