Mkr1400 dont send SMS with only battery

I have a small project with an Mkr1400 and ADXL345
When the MKR intercept an interrupt from accelerometer one SMS is sent to my cell phone.

The project works fine when i debug with USB Cable plus LiO o(via Arduino IDE) but if i plug
only the LiPo Battery the Mkr dont send SMS

Any suggestions???

Hi @c1p81,

Could you please share the sketch you are using.

this is my sketch
it’a only a proof of concept made by cut and paste
the idea is sending an SMS when the MKR receive an interrupt from ADXL345

the sketch works fine when i debug inside IDE but dont work when i disconnect the microUSB
powering only via LiPo

thanks in advance

#include <MKRGSM.h>

GSM gsmAccess;
GSM_SMS sms;

#include <SparkFun_ADXL345.h>         // SparkFun ADXL345 Library

ADXL345 adxl = ADXL345();             // USE FOR I2C COMMUNICATION
int interruptPin = 2;                 // Setup pin 2 to be the interrupt pin (for most Arduino Boards)

void setup(){
  while (!Serial)
  Serial.println("SMS Messages Sender");

  // Start the serial terminal
  Serial.println("SparkFun ADXL345 Accelerometer Hook Up Guide Example");
  adxl.powerOn();                     // Power on the ADXL345

  adxl.setRangeSetting(16);           // Give the range settings
                                      // Accepted values are 2g, 4g, 8g or 16g
                                      // Higher Values = Wider Measurement Range
                                      // Lower Values = Greater Sensitivity

  adxl.setSpiBit(0);                  // Configure the device to be in 4 wire SPI mode when set to '0' or 3 wire SPI mode when set to 1
                                      // Default: Set to 1
                                      // SPI pins on the ATMega328: 11, 12 and 13 as reference in SPI Library 
  adxl.setActivityXYZ(1, 0, 0);       // Set to activate movement detection in the axes "adxl.setActivityXYZ(X, Y, Z);" (1 == ON, 0 == OFF)
  adxl.setActivityThreshold(75);      // 62.5mg per increment   // Set activity   // Inactivity thresholds (0-255)

  adxl.setInactivityXYZ(1, 0, 0);     // Set to detect inactivity in all the axes "adxl.setInactivityXYZ(X, Y, Z);" (1 == ON, 0 == OFF)
  adxl.setInactivityThreshold(75);    // 62.5mg per increment   // Set inactivity // Inactivity thresholds (0-255)
  adxl.setTimeInactivity(10);         // How many seconds of no activity is inactive?

  adxl.setTapDetectionOnXYZ(0, 0, 1); // Detect taps in the directions turned ON "adxl.setTapDetectionOnX(X, Y, Z);" (1 == ON, 0 == OFF)

  // Set values for what is considered a TAP and what is a DOUBLE TAP (0-255)
  adxl.setTapThreshold(50);           // 62.5 mg per increment
  adxl.setTapDuration(15);            // 625 μs per increment
  adxl.setDoubleTapLatency(80);       // 1.25 ms per increment
  adxl.setDoubleTapWindow(200);       // 1.25 ms per increment

  // Set values for what is considered FREE FALL (0-255)
  adxl.setFreeFallThreshold(7);       // (5 - 9) recommended - 62.5mg per increment
  adxl.setFreeFallDuration(30);       // (20 - 70) recommended - 5ms per increment

  // Setting all interupts to take place on INT1 pin
  //adxl.setImportantInterruptMapping(1, 1, 1, 1, 1);     // Sets "adxl.setEveryInterruptMapping(single tap, double tap, free fall, activity, inactivity);" 
                                                        // Accepts only 1 or 2 values for pins INT1 and INT2. This chooses the pin on the ADXL345 to use for Interrupts.
                                                        // This library may have a problem using INT2 pin. Default to INT1 pin.
  // Turn on Interrupts for each mode (1 == ON, 0 == OFF)
attachInterrupt(digitalPinToInterrupt(interruptPin), ADXL_ISR, RISING);   // Attach Interrupt


/****************** MAIN CODE ******************/
/*     Accelerometer Readings and Interrupt    */
void loop(){
  // Accelerometer Readings
  int x,y,z;   
  adxl.readAccel(&x, &y, &z);         // Read the accelerometer values and store them in variables declared above x,y,z

  // Output Results to Serial
  Serial.print(", ");
  Serial.print(", ");
  Serial.println(z); */
  // You may also choose to avoid using interrupts and simply run the functions within ADXL_ISR(); 
  //  and place it within the loop instead.  
  // This may come in handy when it doesn't matter when the action occurs. 


/********************* ISR *********************/
/* Look for Interrupts and Triggered Action    */
void ADXL_ISR() {
  // getInterruptSource clears all triggered actions after returning value
  // Do not call again until you need to recheck for triggered actions
  byte interrupts = adxl.getInterruptSource();
  // Free Fall Detection
  if(adxl.triggered(interrupts, ADXL345_FREE_FALL)){
    Serial.println("*** FREE FALL ***");

    //add code here to do when free fall is sensed
  // Inactivity
  if(adxl.triggered(interrupts, ADXL345_INACTIVITY)){
    Serial.println("*** INACTIVITY ***");
     //add code here to do when inactivity is sensed
  // Activity
  if(adxl.triggered(interrupts, ADXL345_ACTIVITY)){
    Serial.println("*** ACTIVITY ***"); 
     //add code here to do when activity is sensed
  // Double Tap Detection
  if(adxl.triggered(interrupts, ADXL345_DOUBLE_TAP)){
    Serial.println("*** DOUBLE TAP ***");
     //add code here to do when a 2X tap is sensed
  // Tap Detection
  if(adxl.triggered(interrupts, ADXL345_SINGLE_TAP)){
    Serial.println("*** TAP ***");
            bool connected = false;

  // Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes
  while (!connected) {
    if (gsmAccess.begin() == GSM_READY) {
      connected = true;
    } else {
      Serial.println("Not connected");

  sms.print("Luca mi ha toccato");

while (!Serial)

Try remove that...