In IoT, LCD is rarely required, but some times its useful to monitor errors and connection related issues. In this tutorial we are interfacing I2C LCD with ESP8266 or ESP32. Both code examples are given.
We have very few IOs on ESP8266 and ESP32. I2C based display interface uses only two IO lines.
In this tutorial we interface 16×2 LCD display with ESP8266 NodeMCU without using I2C and with minimum pins i.e. using only 3 pins. To interface LCD with ESP8266 we need at least 6 IO lines but ESP already have very few IO lines, to expand IO lines we use serial to parallel shift register IC 74HC595. Continue reading ESP8266 NodeMCU 16×2 LCD Interface→
Resistive touch screen displays are composed of multiple layers that are separated by thin spaces. Pressure applied to the surface of the display by a finger or stylus causes the layers to touch, which completes electrical circuits and tells the device where the user is touching.
We have seen parallel interface technique using Arduino library and we know that it requires 6 IO Lines, Now let’s see how we can reduce required IO’s using 74HC595. We know that we can reduce number IO required by using I2C based LCD interface circuit; It costs ten times more than 74HC595 Circuit.
To connect LCD display 16×2 or 20×4 to Arduino you know you’ll need at least 6 wires to connect, it means sacrificing some IO’s that could be used for connecting other components such as sensors or motors. another way is to use 74HC595 Shift register for interfacing. In this tutorial we will discuss on PCF8574 I2C LCD Display Interface.
A module that can be used to circumvent this problem is the I2C Module for LCD Display with PCF8574 (datasheet ):