====== I²C LCD Display ======
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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. 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.\\ 
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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 adapters, I got mine from eBay, I can't really link it because the links to eBay items seem to die fairly quickly.\\ 
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If you do a search for something like this:
    Yellow Green Serial IIC/I2C/TWI 2004 20X4 Character LCD Module For Arduino
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Then you should find what you are looking for.\\ 
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Here is the description for what I purchased (obviously you can ignore the Arduino references)\\ 
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Yellow Green Serial IIC/I2C/TWI 2004 20X4 Character LCD Module For Arduino  
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    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
    
    5V power supply, the device address 0x27
    
    Compatible to Arduino
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There are many of these available on eBay in 2016, and they average around £3.50-£4.00\\ 
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Here is one connected to a Pi Zero (1.3)\\ 
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{{:lcd_i2c_003b.jpg?200|}}{{:lcd_i2c_002s.jpg?200|}}\\ 
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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.\\ 
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    https://www.youtube.com/watch?v=fR5XhHYzUK0
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This guide assumes that you have installed Raspbian (or equivalent) and updated everything with the following commands:
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    sudo apt-get update
    sudo apt-get upgrade
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On the LCD the four connections will be labelled something like:
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    LCD          R-Pi
    
    GND (Ov)     Pin 6
    VCC (5v)     Pin 2
    SDA          Pin 3 (GPIO2)
    SCL          Pin 5 (GPIO3)
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You need to ensure that the I2C pins are active:
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    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
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Once the OS is installed and the LCD is connected, the libraries can be installed:\\ 
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Ensure you are in  your home folder (probably /home/pi)\\ 
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From the command line:
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    git clone https://github.com/the-raspberry-pi-guy/lcd
    
    cd lcd
    
    sudo sh install.sh (RPi will auto reboot)
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If you can't find the repository - these files may help - {{ :i2c_lcd.zip |}}
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Once the Pi has rebooted: 
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    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)
    
    You can find the LCD address by using a tool called i2cdetect
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I found this guide by doing this YouTube search:
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    Raspberry Pi - Mini LCD Display Tutorial by TheRaspberryPiGuy
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To start the demo LCD code:
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    sudo python lcd_lcd.py
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You should now have some text on the LCD\\ 
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