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User LEDs

This documentation includes installation guidelines and sample code for your hardware.

Overall Info

There are two user LEDs available onboard.

LED Connections

  • LED 1 (Blue): D2.
  • LED 2 (Red): D3.

Arduino Library

There is no need to add a library to control LEDs. All you need to do is defining LED pin numbers, setting pin directions and controlling them.


To initialize the LEDs, first define the connections.
#define LED_B 2
#define LED_R 3
Then, set the pin directions as output.
pinMode(LED_B, OUTPUT)
pinMode(LED_R, OUTPUT)
Now, the LED configuration is ready.

Basic Members

Digital Write

Turns LEDs on or off.
digitalWrite(pin, value);
  • Parameters
    • Pin: LED pin.
    • Value: LED state. "HIGH" or "LOW".
  • Returns
    • None


You can open the example from Arduino IDE > File > Examples > Examples from Custom Libraries > Turta MKR Sensor Shield > User LEDs. There is one example of this sensor.
This application demonstrates blinking of the LEDs.
To run the example:
  1. 1.
    Open the LED Blink sketch from the examples menu.
  2. 2.
    Select your Arduino MKR series board from the Tools > Board menu.
  3. 3.
    Select your device's COM port from Tools > Port menu.
  4. 4.
    Open Serial Monitor from Tools > Serial Monitor.
  5. 5.
    Select 115.200 baud from the Serial Monitor's status bar.
  6. 6.
    Upload the code to your device.
Sample Code
// Define LED connections
#define LED_B 2
#define LED_R 3
void setup() {
// Initialize LEDs
pinMode(LED_B, OUTPUT);
pinMode(LED_R, OUTPUT);
void loop() {
// Turn on Blue LED
digitalWrite(LED_B, HIGH);
// Turn on Red LED
digitalWrite(LED_R, HIGH);
// Turn off Blue LED
digitalWrite(LED_B, LOW);
// Turn off Red LED
digitalWrite(LED_R, LOW);
After the application is uploaded to the device, it turns the LEDs on and off continuously.
The application runs forever until you clear it from memory.