I’ll also show you how to program the LCD using Python, and provide examples for how to print and position the text, clear the screen, scroll text, print data from a sensor, print the date and time, and print the IP address of your Pi. I’ll explain how to connect it both ways in a minute. The PCF8574 converts the I2C signal sent from the Pi into a parallel signal that can be used by the LCD.
But the hardcore DIY way is to use a standard HD44780 LCD and connect it to the Pi via a chip called the PCF8574. The simplest is to get an LCD with an I2C backpack.
There are a couple ways to use I2C to connect an LCD to the Raspberry Pi. It covers all of the steps, diagrams, and code you need to get started. BONUS: I made a quick start guide for this tutorial that you can download and go back to later if you can’t set this up right now.