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--- i2c_lcd_display [2016/08/01 19:56] – created walkeradmin
+++ i2c_lcd_display [2023/03/09 22:35] (current) – external edit 127.0.0.1
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-LCDs are a great way to display simple information (like an IP address) without going to the expense of a full LCD panel, or connecting a monitor.
+LCDs are a great way to display simple information (like an IP address) without going to the expense of a full LCD panel, or connecting a monitor. For my previous LCD I used a 2 line LCD in 4 bit mode, this is a very simple implementation, but it uses lots of GPIO pins.\\
+\\
+Another way to connect an LCD is to use the I2C interface. This only requires a total of 4 wires, two for the data, 2 for power. You can buy LCDs with built in I2C adaptors, I got mine from eBay, I can't really link it because the links to eBay items seem to die fairly quicly.\\
+\\
+If you do a search for something like this:
+    Yellow Green Serial IIC/I2C/TWI 2004 20X4 Character LCD Module For Arduino
+\\
+Then you should find what you are looking for.\\
+\\
+Here is the description for what I purchased (obviously you can ignore the Arduino references)\\
+\\
+Yellow Green Serial IIC/I2C/TWI 2004 20X4 Character LCD Module For Arduino
+\\
+    Dedicated IIC control for Arduino, it only takes two IO
+    Adjustable contrast, the backlight control to provide library
+    High quality LCD screen, Yellow Green, clear display
+    IIC bus control, it only takes two IO ports
+    Backlight control, you can control via a jumper, you can also program control
+    Adjustable display contrast
+V power supply, the device address 0x27
+    Compatible to Arduino
+\\
+There are many of these available on eBay in 2016, and they average around £3.50-£4.00\\
+\\
+Here is one connected to a Pi Zero (1.3)\\
+\\
+{{:lcd_i2c_003b.jpg?200|}}{{:lcd_i2c_002s.jpg?200|}}\\
+\\
+The most tricky part of getting any LCD to run is finding a driver/library for it. I have followed a tutorial from a chap called **TheRaspberryPiGuy** who you can look up on YouTube.\\
+\\
+This guide assumes that you have installed Raspbian (or equivalent) and updated everything with the following commands:
+\\
+    sudo apt-get update
+    sudo apt-get upgrade
+\\
+On the LCD the four connections will be labelled something like:
+\\
+    LCD          R-Pi
+    GND (Ov)     Pin 6
+    VCC (5v)     Pin 2
+    SDA          Pin 3 (GPIO2)
+    SCL          Pin 5 (GPIO3)
+\\
+You need to ensure that the I2C pins are active:
+\\
+    sudo raspi-config
+    Advanced Options
+    I2C
+    Where you see the message -  Would you like the ARM I2C interface to be enabled?
+    Select Yes, then exit this menu system
+    Reboot for the changes to take effect
+\\
+Once the OS is installed and the LCD is connected, the libraries can be installed:
+\\
+Ensure you are in  your home folder (probably /home/pi)\\
+\\
+From the command line:
+\\
+    git clone https://github.com/the-raspberry-pi-guy/lcd
+    cd lcd
+    sudo sh install.sh (RPi will auto reboot)
+\\
+Once the Pi has rebooted:
+\\
+    Navigate to your home folder (probably /home/pi)
+    cd lcd
+    edit lcddriver.py to ensure the ADDRESS = 0x27 is the correct address (some are 0x20)
+\\
+I found this guide by doing this YouTube search:
+\\
+    Raspberry Pi - Mini LCD Display Tutorial by TheRaspberryPiGuy
+\\
+To start the demo LCD code:
+\\
+    sudo python lcd_lcd.py
+\\
+You should now have some text on the LCD\\
+\\