MKRWAN1300 behaving differently when connected to a battery?

Hardware MKR Family MKRWAN1300
#1

Hi there,

I am using a simple code to turn on my LED when a button is pushed and when the sharp sensor detects something close. Below is my code to do this:

const int buttonPin = 2;     // the number of the pushbutton pin
const int ledPin =  5;      // the number of the LED pin
#define SHARP_PIN A1 // Sharp pin number
 
// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status
 
void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT_PULLUP);
}
 
void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);
 float distSharp = analogRead(SHARP_PIN);
 
  // check if the pushbutton is pressed.
  // if it is, the buttonState is HIGH:
  if (buttonState == LOW) {
    // turn LED on:
    digitalWrite(ledPin, LOW);
    Serial.println(buttonState);
    
  } else {
    // turn LED off:
    digitalWrite(ledPin, HIGH);
    Serial.println(buttonState);
    Serial.println(distSharp);
    delay(1000);
//     Serial.println(distSharp);
  }
   if( distSharp > 250 ){ // I
   digitalWrite( ledPin, HIGH ); // Turn on the power to the LED pin
       Serial.println(distSharp);
//       delay(2000);
   } 
else {
     digitalWrite( ledPin, LOW ); // Turn off the power to the LED pin
         Serial.println(distSharp);
//              delay(1000);
   }  
}

The code seems to work fine when I connect the Arduino MKR WAN1300 via USB to my computer. However, when I connect it with a battery, the LED just turns ON all the time. I would like the LED to work the same way when its connected to the PC.

Please help

#2

Hello KingVichai.
Is your whole code here?
If so, while using the PC USB, does the the Serial.println debugs works correctly also?

I miss the common Serial.begin(BAUD); and while(!Serial) lines. Remember to treat it correctly when not using the PC USB. If you need a sample code I can suggest you, just ask.

Also, how is the sharp sensor powered on the 2 scenarios?
Please give us a little more information so we can help you better.

Regards.

#3

Further details are needed as asked also by mjunior, however it seems strange that the code, as is, does what you want when USB powered . Check these details:

 // turn LED off:
   digitalWrite(ledPin, HIGH);

and

digitalWrite( ledPin, HIGH ); // Turn on the power to the LED pin

and

  if (buttonState == LOW) {
    // turn LED on:
    digitalWrite(ledPin, LOW);

Something is clearly wrong, and likely it is going ok only by chance.

#4