ESP8266 Relay board

This page describes the first version of the ESP8266 relay board. For the newer version which includes a usb-serial converter click here.

Features

  • 2 relays
  • DHT22 temperature and humidity sensor
  • GPIO and programming header
  • On board LM1117 linear voltage regulator (3.3v)

Schematic

esp8266relayboard_schematic-1024x725

Note: R2 and R5 should be left unpopulated. These two resistors can be used as pulldown resistor for the gpio pins if the output indication leds are not installed.

Firmware

The firmware that I originally made for this project has become outdated. You can still try to use it but I reccomend programming your own firmware for the board using the Espressif SDK or Arduino.

Programming the board

To program the firmware into the ESP8266 an external usb-serial adapter is needed.

Connect the ground, RX and TX of your usb-serial converter to the correct pins on the board (see schematic).
Remove power from the board and press button 2 (see picture). Now switch the power on again while holding button 2. The ESP8266 has now started in firmware downloading mode.

For Windows a tool like nodemcu-flasher can be used to flash the firmware. For linux I suggest esptool, which is included with the example firmware that you can find on this page.

button2

Pictures

img_20150415_133306

pcb

img_20150302_001806

kit

Github links

https://github.com/rnplus/ESP8266-relay-board-hardware

https://github.com/rnplus/ESP8266-relay-board-firmware