The Relay Board for Micro:bit by MonkMakes (Part ID: 1) is a versatile electronic module designed to enable the Micro:bit to control high-power devices. This relay board acts as an electrically operated switch, allowing the Micro:bit to toggle devices such as lights, motors, or other appliances on and off using low-power signals. It is an essential component for projects requiring the control of external devices that operate at higher voltages or currents than the Micro:bit can handle directly.

• Home automation projects (e.g., controlling lights or fans)
• Robotics (e.g., activating motors or actuators)
• IoT (Internet of Things) applications
• Educational projects to demonstrate relay operation
• Prototyping circuits that require high-power switching

The following table outlines the key technical details of the Relay Board for Micro:bit:

The relay board has the following pin connections:

1. Connect the Relay Board to the Micro:bit:

   • Connect the VCC pin of the relay board to the 3V pin on the Micro:bit.
   • Connect the GND pin of the relay board to the GND pin on the Micro:bit.
   • Connect the IN pin of the relay board to a GPIO pin on the Micro:bit (e.g., Pin 0).

2. Connect the External Device:

   • Identify whether the device should be connected to the NO (Normally Open) or NC (Normally Closed) terminal based on your application.
   • Connect one terminal of the device to the COM pin and the other terminal to either NO or NC.

3. Power the Circuit:

   • Ensure the Micro:bit is powered via USB or a battery pack.
   • If the external device requires a separate power source, connect it appropriately.

4. Control the Relay:

   • Use the Micro:bit to send a HIGH signal (3.3V) to the IN pin to activate the relay and switch the connected device.

• Isolation: Ensure proper electrical isolation when working with high-voltage devices to avoid damage or injury.
• Current Ratings: Do not exceed the relay's maximum current rating of 10A.
• Flyback Diode: The relay board includes a built-in flyback diode to protect the Micro:bit from voltage spikes caused by the relay coil.
• GPIO Pin Current: The Micro:bit GPIO pins can safely drive the relay board without additional components.

Below is an example of how to control the relay board using the Micro:bit:

from microbit import *

relay_pin = pin0

while True: # Turn the relay ON for 2 seconds relay_pin.write_digital(1) # Send HIGH signal to activate the relay sleep(2000) # Wait for 2 seconds

# Turn the relay OFF for 2 seconds
relay_pin.write_digital(0)  # Send LOW signal to deactivate the relay
sleep(2000)  # Wait for 2 seconds

1. The relay does not activate:

   • Ensure the VCC and GND pins are properly connected to the Micro:bit.
   • Verify that the IN pin is receiving a HIGH signal (3.3V) from the Micro:bit.
   • Check the power source for the Micro:bit and ensure it is sufficient.

2. The connected device does not turn on/off:

   • Confirm that the device is correctly connected to the COM and NO or NC terminals.
   • Ensure the external device's power source is properly connected and functional.

3. The relay clicks but the device does not respond:

   • Verify the voltage and current requirements of the connected device.
   • Ensure the relay's maximum ratings (240V AC / 30V DC, 10A) are not exceeded.

4. Micro:bit resets when activating the relay:

   • This may occur if the relay draws too much current. Use a separate power supply for the relay board if necessary.

Q: Can I use the relay board with other microcontrollers?
A: Yes, the relay board is compatible with other microcontrollers that operate at 3.3V or 5V logic levels, such as Arduino or Raspberry Pi.

Q: Is the relay board safe for high-voltage applications?
A: The relay board is designed to handle up to 240V AC, but proper precautions must be taken when working with high voltages to ensure safety.

Q: Can I control multiple relay boards with a single Micro:bit?
A: Yes, you can control multiple relay boards by connecting each board's IN pin to a separate GPIO pin on the Micro:bit.

Q: Does the relay board make noise when switching?
A: Yes, the relay produces a clicking sound when it switches states, which is normal for mechanical relays.