• @Gordon yes that off course fixed the issue i have ;-). I've changed my code over the day it works like aspactad.

    let started = false;  // if scanning is startet
    var intervalLed;
    var selfid = NRF.getAddress().substr(12,5).replace(':­',''); // get the last 5 digits of ble mac as id
    var scanIds = [ "5c5b", "69f0", "6d31" ];  // list of devices to scan for
    var data = new Uint8Array(scanIds.length); // define data as zero
    
    // Default ble settings
    const be = {
          name: "BLE "+ selfid, // The name of the device
          showName: true, // include full name, or nothing
          discoverable: true, // general discoverable, or limited - default is limited
          connectable: true, // whether device is connectable - default is true      
          scannable : true, // whether device can be scanned for scan response packets - default is true
          interval: 375, // Advertising interval in msec, between 20 and 10000 (default is 375ms)
          manufacturer: 0x0590, // IF sending manufacturer data, this is the manufacturer ID
        };
    
    // update Advertising by the current received rssi
    function updateAdvertising(device) {
      // our data - all 0 for nothing, 
      // or RSSI + 6 bytes address
      var id = device.id.substr(12, 5).replace(':','');
    
      if (!scanIds.includes(id)) return;
    
      data[scanIds.indexOf(id)] = device.rssi * -1; // converte to positive integer
    
      NRF.setAdvertising({}, {
        showName: false,
        connectable: false,
        scannable: false,
        interval: 100,
        manufacturer: be.manufacturer,
        manufacturerData: data
      });
      
      console.log("Found Device: " + id);
    }
    
    function setDefault() {
      // Initiale Advertising
      NRF.setAdvertising({}, {
        name: be.name,
        showName: be.showName,
        discoverable: be.discoverable,
        connactable: be.connectable,
        scannable: be.scannable,
        interval: be.interval,
        manufacturer: be.manufacturer,
        manufacturerData: data
      });
    }
    
    Pin.prototype.flash = function(period) { 
      var pin = this;
      digitalWrite(pin, true);
      setTimeout(function() {
        digitalWrite(pin, false);
      }, 100);
    };
    
    // Setting up defaults
    setDefault();
    
    // Watch if BTN was pressed
    setWatch(function(){
      console.log("Device: " + be.name);
      
      if (started) {
        console.log("Stop Scanning");
        NRF.setScan();  // Stop scanning on BLE devices
        clearInterval(intervalLed); // Stop Led from blinking
        started = false; // switch device status
        LED1.flash(); // Show stop with red LED
        setDefault();
      } else {
        console.log("Start Scanning");
        started = true;
        LED2.flash();  // Show start with green LED
        NRF.setScan(updateAdvertising); // Start scanning for BLE devices
        intervalLed = setInterval('LED2.flash();', 10000); // Flash the green led to visualise scanning mode
      }
    }, BTN, {edge:"rising", repeat:1, debounce:20});
    

    Now i have two new problems. First of all, after starting and stopping, i can't connect to the Puck-js scince i'm pull out the battery and plug it in again.

    ~~The second problem is the advertising interval. If i change the interval to somthing under 100ms i don't reseive any packages from the device. ~~

    [Edit] Answere for the second Question:
    NOTE: Non-connectable advertising can't have an advertising interval less than 100ms according to the BLE spec.

About