ESP8266

esp8266 Documentation

• ESP8266 Datasheet EN v4.3
• ESP8266 Low Power Solutions EN 1.3
• ESP8266 Technical Reference EN
• ESP8266 RAM with PROGMEM
• API Reference
  • ESP8266 NON OS SDK API Reference
  • ESP8266 RTOS SDK API Reference v1.4.0_0

Wifi Relay Board

• Power supply: between 7 and 30V DC
• chipset: ESP8266MOD (ESP8266-12E)
• GPIOO4 is used as output and connected to relay
• GPIOO5 is used as input and connected to PC817 photocoupler
• Flash: Manufacturer 0xe0 Product 0x4016 --> BergMicro BG25Q32 32Mbit ?
• Schematic: wifi_relay.pdf (extracted by http://www.uctronics.com/download/U4648-datasheet.zip (path U4648-datasheet/U4648/sch))
• Source Code: WiFiRelayWebServer-20170225-2152.ino
• esptool usage

  ./esptool.py -p /dev/ttyUSB0 -b 115200 flash_id
  esptool.py v1.3-dev
  Connecting...
  Manufacturer: e0
  Device: 4016
  
  ./esptool.py -p /dev/ttyUSB0 -b 115200 write_flash 0x000000 firmware.bin
  	

• Original software uses yunshan123456789 wifi password and IP is 192.168.4.1

Wemos D1

• Changes between R1 and R2 versions
• Wemos d1 schematics (v2.0.0)

USB Serial Adapter

• DTR: Data Terminal Ready - an output used for flow control
• RX: Serial data Receive pin
• TX: Serial data Transmit pin
• VCC: Positive voltage output - this is controlled by the jumper. If the jumper is set to 5V, this will provide a 5V output. If the jumper is set to 3.3V, this will provide a 3.3V output.
• CTS: Clear To Send - an input used for flow control
• GND: Ground or 0V

The VCC pin is ideal for powering small devices such as homemade circuits. This pin should not be connected when a device has a separate power supply as this may damage both devices.

Please note that in 5V mode the maximum current draw on this pin is approximately 500mA. In 3.3V mode the maximum current draw on VCC is approximately 50mA.