ESP8266 Community Forum

Hi,

I have troubles with my project and I need your help!

Setup:
- ESP8266 NodeMCU DevBoard
- 8 channel relay module 5V
- 16/2 LCD with IC adapter (SDA/SCL)

I want to use the ESP8266 to control the relay and I also need to show static information on the LCD.

- What is the best pin setup for this project?
I currently use the following:

RELAY1 = GPIO16; // D0
RELAY2 = GPIO10; // SD3
RELAY3 = GPIO0; // D3
RELAY4 = GPIO2; // D4
RELAY5 = GPIO14; // D5
RELAY6 = GPIO12; // D6
RELAY7 = GPIO13; // D7
RELAY8 = GPIO15; // D8

LCD SCL = GPIO5; // D1
LCD SDA = GPIO4; // D2

ESP8266 VIN -> 8CHANRELAY VCC

This works as expected when I do not connect VIN to VCC when the ESP is booting but not if it is.

In this thread: viewtopic.php?f=32&t=11614 @martinayotte says that GPIO15 needs to be pulled down while booting...
I also tried to change GPIO15 to GPIO9 - boot fails also. I also want to use GPIO3 and GPIO1 in the future for SERIAL communication so I don't know what to do..

Thanks!

Anyone?

use an i/o-expander for your relay-card.

Some of the inputs might behave different when power is connected to your relay-card.
There might be pull-ups on pins that need to be low during boot.

Especially gpio10 may not be used as it is internally used for the flash memory.

A while ago I was looking also for a reliable and stable solution to driver a large numer of relays (8,16,32,64,etc) and some extras (temp/hum sensors, RTC, etc).

After trying a lot of different configurations I ended up with the result from below, based on a previously designed industrial relay board:


Related Article with hardware details, etc: http://www.esp8266-projects.com/2016/11/wifi-mains-8x-relay-board-for-home.html

It's fully stackable (use one ESP8266 to drive more than one MPRSx8 board thru the onboard nEXT Bus connector) and it is fully compatible with Arduino IDE, ESPBasic, ESPEasy, Raspberry PI, Domoticz,etc. You can find a lot of related youtube videos and software examples for each.