How to Use Adafruit 16x8 LED Matrix Backpack Yellow-Green: Examples, Pinouts, and Specs

The Adafruit 16x8 LED Matrix Backpack Yellow-Green is a compact and versatile display module that allows users to add a bright, eye-catching display to their projects. This LED matrix has 16 columns and 8 rows, providing a total of 128 LEDs in a yellow-green color. It is designed for ease of use and can be controlled via I2C, making it an excellent choice for displaying numbers, letters, and simple graphics. Common applications include wearable electronics, status indicators, message boards, and time displays.

• Display Color: Yellow-Green
• Matrix Size: 16 columns x 8 rows (128 LEDs)
• Operating Voltage: 4.5V - 5.5V
• Max Current (with all LEDs on): 320mA
• Communication: I2C interface
• I2C Addresses: 0x70 (default) - 0x77 (selectable with solder jumpers)
• Dimensions: 1.2" x 2.7" x 0.1" (31mm x 70mm x 2.5mm)

1. Power Connections:

   • Connect the VCC pin to the 5V output on the Arduino.
   • Connect the GND pin to one of the GND pins on the Arduino.

2. I2C Connections:

   • Connect the SDA pin to the A4 pin on the Arduino (SDA).
   • Connect the SCL pin to the A5 pin on the Arduino (SCL).

3. Address Selection:

   • The ADDR pin can be connected to GND or VCC to change the I2C address if multiple displays are used.

To control the LED matrix, you can use the Adafruit LED Backpack library available through the Arduino Library Manager. Here is a simple example code to get started:

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_LEDBackpack.h>

Adafruit_8x16matrix matrix = Adafruit_8x16matrix();

void setup() {
  matrix.begin(0x70); // Start the display at I2C address 0x70
  matrix.setBrightness(15); // Set brightness to a medium level (0-15)
}

void loop() {
  matrix.clear(); // Clear the display buffer
  matrix.setCursor(0, 0); // Set cursor at top-left corner
  matrix.print("Hello"); // Print "Hello" to the buffer
  matrix.writeDisplay(); // Write the buffer to the display
  delay(2000); // Wait for 2 seconds
  matrix.clear(); // Clear the display for the next message
  matrix.setCursor(0, 0); // Reset cursor position
  matrix.print("World"); // Print "World" to the buffer
  matrix.writeDisplay(); // Update the display
  delay(2000); // Wait for 2 seconds
}

• Power Requirements: Ensure that your power supply can handle the maximum current draw when all LEDs are on.
• Brightness Control: Adjust the brightness to suit your application and to prevent excessive power consumption.
• I2C Addressing: Use the ADDR pin to set different addresses if using multiple LED matrices on the same I2C bus.

• Display Not Lighting Up: Check the power connections and ensure the correct I2C address is used in the code.
• Garbled Display: Ensure there are no loose connections and that the I2C lines are connected properly.
• Dim Display: Increase the brightness setting in the code or check the power supply voltage.

• Check Connections: Verify all connections are secure and correct.
• Use External Power: If using multiple LED matrices, consider using an external power supply.
• I2C Scanning: Use an I2C scanner sketch to confirm the address of the LED matrix.

Q: Can I daisy-chain multiple LED matrices? A: Yes, you can connect multiple matrices by setting unique I2C addresses for each and wiring them in parallel.

Q: How do I change the I2C address? A: Solder or otherwise connect the ADDR pin to GND or VCC and modify the address in your code accordingly.

Q: Can I display images on the matrix? A: The matrix is best suited for displaying text and simple graphics due to its resolution.

For further assistance, consult the Adafruit support forums or the detailed product guides available on the Adafruit website.