How to Use Adafruit Mini Relay FeatherWing: Examples, Pinouts, and Specs

The Adafruit Mini Relay FeatherWing (Manufacturer Part ID: 2895) is a compact relay board designed to seamlessly integrate with Adafruit Feather microcontroller boards. It allows users to control high-voltage devices (up to 250V AC or 28V DC) using low-voltage signals from a Feather board. This makes it an ideal solution for projects requiring the control of motors, lights, or other high-power devices.

• Home automation systems (e.g., controlling lights or appliances)
• Robotics (e.g., motor control)
• Industrial control systems
• IoT projects requiring high-voltage switching
• Prototyping and educational projects

The Adafruit Mini Relay FeatherWing is built for reliability and ease of use. Below are its key technical details:

The Mini Relay FeatherWing connects directly to the Feather board via its headers. It also provides screw terminals for connecting external devices. Below is the pin configuration:

The Adafruit Mini Relay FeatherWing is straightforward to use with any Feather board. Follow the steps below to integrate it into your project:

1. Attach the FeatherWing: Plug the Mini Relay FeatherWing onto your Feather board using the provided headers.
2. Connect External Devices:
   • Use the screw terminals to connect the high-voltage device you want to control.
   • Connect the device's power line to the COM terminal.
   • Connect the device's load line to either the NO (Normally Open) or NC (Normally Closed) terminal, depending on your desired behavior:
     • Use NO if you want the device to turn on when the relay is activated.
     • Use NC if you want the device to turn off when the relay is activated.

To control the relay, you can use any Feather-compatible microcontroller. Below is an example of how to control the relay using an Arduino UNO (via Feather-compatible libraries):

// Example code to control the Adafruit Mini Relay FeatherWing
// This code toggles the relay on and off every second.

#define RELAY_PIN 13  // Define the pin connected to the relay control signal

void setup() {
  pinMode(RELAY_PIN, OUTPUT);  // Set the relay pin as an output
  digitalWrite(RELAY_PIN, LOW); // Ensure the relay starts in the OFF state
}

void loop() {
  digitalWrite(RELAY_PIN, HIGH); // Activate the relay
  delay(1000);                   // Wait for 1 second
  digitalWrite(RELAY_PIN, LOW);  // Deactivate the relay
  delay(1000);                   // Wait for 1 second
}

• Power Supply: Ensure your Feather board can supply enough current for the relay. If not, consider using an external power source.
• High-Voltage Safety: When working with high-voltage devices, take proper precautions to avoid electric shock or damage to components.
• Flyback Diode: The FeatherWing includes a built-in flyback diode to protect the circuit from voltage spikes caused by the relay coil. No additional diode is needed.

1. Relay Not Activating:

   • Cause: Insufficient power supply or incorrect wiring.
   • Solution: Verify that the Feather board is supplying the correct voltage (3.3V or 5V) and that the RELAY pin is properly connected.

2. Device Not Turning On/Off:

   • Cause: Incorrect connection to the screw terminals.
   • Solution: Double-check the wiring to the COM, NO, and NC terminals. Ensure the device is connected to the correct terminal based on your desired behavior.

3. Feather Board Resets When Relay Activates:

   • Cause: Relay draws too much current, causing a voltage drop.
   • Solution: Use an external power supply for the Feather board or reduce the load on the relay.

4. Relay Clicking Rapidly:

   • Cause: Software bug or unstable control signal.
   • Solution: Check your code to ensure the RELAY pin is not being toggled unintentionally.

Q: Can I use the Mini Relay FeatherWing with non-Adafruit Feather boards?
A: Yes, as long as the board provides a compatible voltage (3.3V or 5V) and has a GPIO pin to control the relay.

Q: What is the maximum current the relay can handle?
A: The relay can handle up to 10A of current.

Q: Can I control multiple relays with one Feather board?
A: Yes, but you will need additional relay boards and enough GPIO pins to control each relay individually.

Q: Is the relay suitable for switching DC motors?
A: Yes, but ensure the motor's voltage and current are within the relay's specifications (28V DC, 10A max).

By following this documentation, you can effectively integrate the Adafruit Mini Relay FeatherWing into your projects and troubleshoot any issues that arise.