How to Use Adafruit NeoKey FeatherWing: Examples, Pinouts, and Specs

The Adafruit NeoKey FeatherWing (Part ID: 4979) is a versatile input device designed to integrate seamlessly with Adafruit Feather boards. It features two mechanical key switches with customizable RGB LED backlighting, making it ideal for creating compact keyboards, control interfaces, or interactive projects. The NeoKey FeatherWing simplifies the process of adding tactile input and vibrant lighting to your Feather-based designs.

• Custom mechanical keyboards
• MIDI controllers and music interfaces
• Gaming keypads
• Control panels for IoT devices
• Interactive art installations

The Adafruit NeoKey FeatherWing is designed to be user-friendly and compatible with a wide range of Feather boards. Below are its key technical details:

• Number of Keys: 2 mechanical key switches (Kailh-compatible sockets)
• LED Backlighting: Individually addressable RGB LEDs (NeoPixel-compatible)
• Communication Protocol: I2C
• Default I2C Address: 0x30 (configurable via solder jumpers)
• Operating Voltage: 3.3V (logic level)
• Dimensions: 51mm x 23mm x 8mm (excluding keycaps)

The NeoKey FeatherWing connects directly to Feather boards via its headers. Below is the pinout:

1. Attach the FeatherWing: Plug the NeoKey FeatherWing into the headers of your Feather board. Ensure proper alignment of the pins.
2. Install Key Switches: Insert two mechanical key switches into the Kailh-compatible sockets. Add keycaps if desired.
3. Connect Power: The Feather board will supply 3.3V power to the FeatherWing.
4. I2C Communication: The FeatherWing communicates with the Feather board via the I2C protocol. Ensure no address conflicts with other I2C devices.
5. Install Libraries: Use the Adafruit NeoPixel and Adafruit Seesaw libraries to control the RGB LEDs and read key presses.

• I2C Address Configuration: If you need to use multiple NeoKey FeatherWings, modify the I2C address by adjusting the solder jumpers on the back of the board.
• Power Requirements: Ensure your Feather board can supply sufficient current for the RGB LEDs, especially if using multiple FeatherWings.
• Key Switch Compatibility: The sockets are compatible with Kailh mechanical switches. Ensure the switches are properly seated to avoid poor connections.
• Library Installation: Install the required libraries via the Arduino Library Manager for seamless integration.

Below is an example of how to use the NeoKey FeatherWing with an Adafruit Feather board:

#include <Wire.h>
#include "Adafruit_NeoPixel.h"
#include "Adafruit_seesaw.h"

// Create a seesaw object for the NeoKey FeatherWing
Adafruit_seesaw neokey;

// Define the NeoPixel pin and number of LEDs
#define NEOKEY_NEOPIXEL_PIN 3
#define NUMPIXELS 2

Adafruit_NeoPixel pixels(NUMPIXELS, NEOKEY_NEOPIXEL_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10); // Wait for Serial Monitor to open

  // Initialize the NeoKey FeatherWing
  if (!neokey.begin(0x30)) { // Default I2C address is 0x30
    Serial.println("Failed to find NeoKey FeatherWing!");
    while (1) delay(10);
  }
  Serial.println("NeoKey FeatherWing initialized!");

  // Initialize the NeoPixel LEDs
  pixels.begin();
  pixels.setBrightness(50); // Adjust brightness (0-255)
  pixels.show(); // Turn off all LEDs initially
}

void loop() {
  // Check if a key is pressed
  uint8_t keyPressed = neokey.digitalReadBulk();
  if (keyPressed & 0x01) { // Check if key 1 is pressed
    Serial.println("Key 1 pressed!");
    pixels.setPixelColor(0, pixels.Color(255, 0, 0)); // Red for key 1
  } else {
    pixels.setPixelColor(0, 0); // Turn off LED for key 1
  }

  if (keyPressed & 0x02) { // Check if key 2 is pressed
    Serial.println("Key 2 pressed!");
    pixels.setPixelColor(1, pixels.Color(0, 0, 255)); // Blue for key 2
  } else {
    pixels.setPixelColor(1, 0); // Turn off LED for key 2
  }

  pixels.show(); // Update the LEDs
  delay(50); // Small delay for debounce
}

1. NeoKey FeatherWing Not Detected:

   • Ensure the FeatherWing is properly seated on the Feather board.
   • Verify the I2C address matches the one in your code (0x30 by default).
   • Check solder jumpers if you modified the I2C address.

2. RGB LEDs Not Lighting Up:

   • Confirm the NeoPixel library is installed and correctly initialized.
   • Check the power supply; insufficient current can cause LED issues.
   • Verify the brightness setting in your code.

3. Key Presses Not Detected:

   • Ensure the mechanical switches are fully inserted into the sockets.
   • Test the switches with a multimeter to confirm functionality.
   • Check the digitalReadBulk() function for proper key state detection.

• Can I use more than one NeoKey FeatherWing? Yes, but you must configure unique I2C addresses for each FeatherWing by modifying the solder jumpers.

• What key switches are compatible? The NeoKey FeatherWing supports Kailh-compatible mechanical switches.

• How do I change the RGB LED colors? Use the setPixelColor() function from the NeoPixel library to customize the LED colors.

• Is it compatible with non-Adafruit Feather boards? The NeoKey FeatherWing is designed for Adafruit Feather boards but may work with other boards that support 3.3V I2C communication.