What Are Custom LCD Characters? (A Simple Guide)

If you've ever tinkered with an Arduino or Raspberry Pi, you've probably seen the classic blue and white character LCD screens. They're a fantastic way to display text and data, but did you know you're not stuck with just the standard letters and numbers? These little screens have a secret power: a small, special part of their memory called **CGRAM** where you can store up to **eight of your very own custom characters!** Think of it like having eight blank pixel art canvases, each 5 pixels wide and 8 pixels tall. You can draw anything you want in them—a heart icon, a battery level indicator, a little alien, or even different frames for a simple animation. This is the key to making your electronics project feel truly unique and professional.

But how do you tell the screen what to draw? You have to create a "byte array," which is a special list of numbers for the controller. Each number in the list represents a single row of your 5x8 grid, telling the screen exactly which pixels to turn on or off. Doing this by hand involves a lot of tedious binary math and is very easy to get wrong. That's where this tool comes in. It's designed to be your personal pixel art studio and code generator all in one. You can simply click on the grid to draw your character visually, and the tool instantly does all the complicated math for you in the background. It generates the exact, ready-to-use code that you can copy and paste directly into your project. It's about taking the most frustrating part of the process and making it fun, creative, and easy.

How to Use the Generator

Creating a full set of custom characters for your project is a simple, visual process:

1. Select a Character Slot:** Your LCD can store up to 8 custom characters. Click on one of the eight small boxes in the "Character Slots" area to choose which one you want to edit. The active slot will be highlighted.
2. Draw Your Character:** Click on the squares in the main 5x8 pixel grid to turn them on or off. The "on" pixels (the dark ones) will form your final character. For a quick start, try loading a design from the "Load a Preset" dropdown!
3. Customize Your Code:** Give your character set a custom **Variable Name** and choose the **Code Format** you prefer (most Arduino users will want Binary).
4. See the Code Update Instantly:** As you draw and change settings, the Arduino/C code in the output box will update in real-time. It will automatically generate the code for all the characters you've designed.
5. Copy and Paste:** Once you're happy with your full set of characters, click the "Copy" button. You can then paste this complete code block directly into your Arduino sketch or C program.