Crawler Robot with a 16x16 LED Dot-Matrix Display

Overview

It all began with a simple question:
“What if a robot could show what it’s thinking while it moves?”

Crawler robots are excellent at overcoming obstacles, but they often feel silent and purely mechanical. I wanted to give mine something more—a way to express its intentions. To achieve this, I added a 16×16 WS2812B LED matrix to the front of the robot. Rather than serving as a static decoration, the display became the robot’s “face.”

When the robot moves forward, a bold arrow appears. When it turns, the arrow shifts to match its direction. These small visual cues transform the robot from a cold machine into something that feels more like a tiny creature with purpose and awareness.

The robot receives its movement commands wirelessly using the ESP-NOW protocol. At the heart of the system is a Seeed Studio XIAO ESP32-C6 microcontroller, which manages both motion control and display logic. A Toshiba TB6612FNG dual motor driver powers the crawler’s motors, while the 16×16 WS2812B LED dot-matrix panel brings its actions to life with bright, crisp arrow animations.

Hardware Requirements

Crawler Components

• Microcontroller: Seeed Studio XIAO ESP32-C6
• Motor Driver: Toshiba TB6612FNG dual motor driver
• Crawler Kit: SZDOIT TP101 Robot Tank Car Kit
• Dot-Matrix Display: 16x16 WS2812B LED dot-matrix panel
• Rechargeable Ni-MH AA Battery x 4 (4.8V)

Joystick Components

• Microcontroller: Seeed Studio XIAO ESP32-C3
• Joystick: KY-023
• Rechargeable Ni-MH AA Battery x 4 (4.8V)

Crawler Pin Connections

| XIAO ESP32-C6 Pin | TB6612FNG Pin  | Dot-matrix display Pin  | Battery Pin |
| ----------------- | -------------- | ----------------------- | ----------- |
| D0                | PWMA           | -                       | -           |
| D1                | AIN2           | -                       | -           |
| D2                | AIN1           | -                       | -           |
| D3                | BIN1           | -                       | -           |
| D4                | BIN2           | -                       | -           |
| D5                | PWMB           | -                       | -           |
| D7                | -              | DIN                     | -           |
| D8                | -              | -                       | -           |
| D9                | -              | -                       | -           |
| D10               | STBY           | -                       | -           |
| 3V3               | VCC            | -                       | -           |
| GND               | GND            | GND                     | GND         |
| VBUS              | -              | -                       | VBAT        |
| -                 | VM             | -                       | VBAT        |
| -                 | -              | 5V                      | VBAT        |

Joystick Pin Connections

| XIAO ESP32-C3 Pin | Joystick Pin | Battery Pin |
| ----------------- | ------------ | ----------- |
| A0                | VRX          |             |
| A1                | VRY          |             |
| GND               | GND          | GND         |
| VBUS              | +5V          | VBAT        |

Software Requirements

Crawler Source Code

GitHub

Project Structure

dotmatrix_crawler_robot/
├── src/
│   └── main.cpp                    # Main program logic
├── include/
│   ├── constants.h                 # Pin definitions and configuration
│   ├── motor_controller.hpp        # Motor control interface
│   ├── led_display.hpp             # LED dot-matrix display interface
│   ├── animation_controller.hpp    # Animation manager
│   └── arrow_images.h              # Pregenerated arrow image data
├── platformio.ini                  # PlatformIO configuration
└── README.md                       # Document

Dependencies

• FastLED - LED dot-matrix control
• LovyanGFX - Graphics rendering

Joystick Source Code

GitHub

Project Structure

dotmatrix_crawler_joystick/
├── src/
│   └── main.cpp              # Main program logic
├── include/
│   └── constants.h           # Configuration constants and pin definitions
├── platformio.ini            # PlatformIO configuration
└── README.md                 # Document

How to Change the Images

• Open the image with GIMP.
• Click [File] > [Export As...].
• Click [Select File Type (By Extension)].
• Select [C source code].
• Click the [Export] button.
• Open the exported file.
• Copy the data section enclosed in double quotation marks and replace the corresponding element in the "arrowImg" array within "include/arrow_images.h".