How to Use Adafruit ANO Rotary Encoder to I2C Adapter: Examples, Pinouts, and Specs

The Adafruit ANO Rotary Encoder to I2C Adapter is a compact module designed to simplify the integration of a rotary encoder into projects that utilize the I2C communication protocol. Rotary encoders are electromechanical devices that convert the angular position or motion of a shaft or axle to an analog or digital signal. This adapter allows for the rotary encoder's output to be easily read over the I2C bus, making it ideal for applications such as user interfaces, menu navigation, or input devices in embedded systems.

• Volume control in audio equipment
• Menu selection in user interfaces
• Position input for robotics
• Scrolling input for displays

• Operating Voltage: 3.3V to 5V
• I2C Address: Configurable
• Dimensions: 18mm x 18mm x 2mm

1. Connect the VCC pin to the power supply (3.3V or 5V, depending on your system).
2. Connect the GND pin to the ground of your system.
3. Connect the SDA and SCL pins to the I2C data and clock lines, respectively.
4. (Optional) Connect the INT pin to an interrupt-capable pin on your microcontroller if you wish to use the interrupt feature.

• Ensure that pull-up resistors are in place for the SDA and SCL lines if they are not already provided by the microcontroller.
• Avoid long wires for the I2C connection to minimize signal degradation.
• Use the interrupt pin to detect rotary encoder changes without polling the I2C bus, which can save power and processing time.

#include <Wire.h>

// Define the I2C address for the rotary encoder (check your module documentation)
#define ENCODER_I2C_ADDRESS 0x40

void setup() {
  Wire.begin(); // Join the I2C bus as a master
  Serial.begin(9600); // Start serial communication for debugging
}

void loop() {
  Wire.requestFrom(ENCODER_I2C_ADDRESS, 2); // Request 2 bytes from the encoder
  if(Wire.available() == 2) {
    int position = Wire.read(); // Read the first byte, which is the low byte
    position |= Wire.read() << 8; // Read the second byte, which is the high byte
    Serial.println(position); // Print the position value to the serial monitor
  }
  delay(100); // Small delay to prevent spamming the I2C bus
}

• I2C Communication Failure: Ensure that the SDA and SCL lines are connected correctly and that pull-up resistors are in place.
• Inaccurate Position Values: Check for any mechanical issues with the rotary encoder or electrical noise affecting the signal.

• Use the Arduino's built-in Wire library functions such as Wire.beginTransmission() and Wire.endTransmission() to check for errors in communication.
• If using the interrupt feature, ensure that the microcontroller's interrupt pin is configured correctly in your code.

Q: Can I change the I2C address of the adapter? A: Yes, the I2C address is configurable. Refer to the Adafruit documentation for the specific procedure.

Q: What is the maximum rotation speed the adapter can handle? A: The maximum rotation speed will depend on the specific rotary encoder used and the I2C bus speed. Check the datasheet of your rotary encoder for more details.

Q: Is it possible to connect multiple encoders to the same I2C bus? A: Yes, as long as each encoder has a unique I2C address, you can connect multiple encoders to the same bus.

Remember to consult the Adafruit ANO Rotary Encoder to I2C Adapter datasheet for more detailed information and specifications.