Whether you’re a veteran STEM teacher or just beginning to integrate electronics into your curriculum, teaching students how microcontrollers and LCDs work together is a great gateway into the world of embedded systems. In this lesson, we’ll walk through a beginner-friendly project that brings characters to life on a 16×2 character LCD using an Arduino-compatible Seeeduino microcontroller.
Lesson Overview
- Grade Level: High school (grades 10-12) or early college
- Subject: STEM / Electronics / Computer Science
- Length: 1-2 class periods (45–90 minutes)
- Objective: Students will connect a character LCD to a microcontroller and write code to display a message.
- Skills Developed:
- Circuit building and troubleshooting
- Understanding LCDs and microcontroller interfacing
- Introductory embedded programming using Arduino IDE
Materials Needed
| Item | Quantity | Link |
|---|---|---|
| CFAH1602B-NYG-JT 16×2 Character LCD | 1 per student/team | LCD product page |
| Seeeduino Microcontroller (Arduino-compatible) | 1 per student/team | Microcontroller product page |
| Breadboard & Jumper Wires | 1 set per student/team | Dev Kit with Potentiometer |
| 10kΩ Potentiometer | 1 per LCD (for contrast control) | — |
| USB Cable for Seeeduino | 1 per student/team | 6′ USB-C to MicroUSB |
| Computer with Arduino IDE installed | 1 per student/team | Download Arduino IDE |
| (Optional) 220Ω resistor and LED for power testing | 1 set |
Teacher Preparation
Before class:
- Familiarize yourself with wiring a character LCD using 4-bit parallel mode.
- Pre-test the circuit and code to verify the LCD works with the Seeeduino.
- Print or display a pinout diagram of the CFAH1602B for students.
Step-by-Step Instructions
🛠 Part 1: Wiring the LCD to the Microcontroller
Use the 4-bit mode for simplicity (fewer wires). Here’s the basic wiring chart:
| LCD Pin | Function | Connect To |
|---|---|---|
| 1 (VSS) | Ground | GND on Seeeduino |
| 2 (VDD) | +5V Power | 5V on Seeeduino |
| 3 (VO) | Contrast | Center of 10k pot |
| 4 (RS) | Register Select | Pin 12 |
| 5 (RW) | Read/Write | GND (write only) |
| 6 (E) | Enable | Pin 11 |
| 11-14 | Data Pins D4–D7 | Pins 5, 4, 3, 2 |
| 15, 16 | Backlight | 5V and GND (optional) |
🧠 Tip for students: Always double-check connections before powering the board. Reverse polarity can damage the display!
💻 Part 2: Writing the Code
cppCopyEdit#include <LiquidCrystal.h>
// Pin setup: RS, E, D4, D5, D6, D7
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
void setup() {
lcd.begin(16, 2); // 16 columns, 2 rows
lcd.print("Hello, world!"); // Print a message to the LCD
}
void loop() {
// Nothing to do here
}
➡️ Upload this code using the Arduino IDE and watch the magic happen.
Teaching Tips
- Explain the pin roles: Use the opportunity to talk about digital vs. analog pins, control vs. data signals, and binary communication.
- Explore VO contrast: Turn the potentiometer knob to show how contrast changes the visibility of characters.
- Ask questions: For example, what happens if you swap data lines D4 and D5? What if RW isn’t grounded?
- Encourage modifications: Challenge students to display their name or animate characters across the screen.
Troubleshooting Common Issues
| Problem | Solution |
|---|---|
| LCD lights up but shows no text | Adjust the contrast potentiometer |
| Display is garbled | Check if data pins are correctly wired |
| Nothing happens at all | Ensure power/ground connections are secure |
| Compiler errors | Verify LiquidCrystal library is included correctly |
Extension Activities
- Display sensor data (e.g., temperature using a TMP36).
- Create a simple menu system with push buttons.
- Design an interactive quiz or game interface.
Learning Outcomes
By the end of this lesson, students should be able to:
- Identify the function of each pin on a character LCD.
- Wire a basic embedded system using a microcontroller and display.
- Write and modify Arduino code to control the LCD.
- Understand how microcontrollers interact with hardware peripherals.
Closing Thought
LCDs are more than old-school calculator screens—they’re a perfect bridge between code and real-world electronics. Once your students can display “Hello, World,” they’re well on their way to building interactive devices, custom dashboards, and even their own handheld gadgets.
Ready to level up your classroom tech? This simple lesson might just light up more than a display—it could spark a passion for hardware and coding that sticks for life.
Jeffrey Nystrom is an engineering technician at Crystalfontz. He graduated from ITT Technical Institute of Technology with his B.S. in Electronics Engineering. In his position, Jeff engages in customer technical support, works on engineering projects, and supports Crystalfontz’s manufacturing operations. Outside of the office, Jeff enjoys working in his shop, tinkering with his 3D printer, and going on new adventures with his family.