StartNotification doesn't return me callback success or callback error

[AngeNew]

Hi, I use startNotification to handle measure of IMU sensor, at startNotification sensor should me a constant signal of measures, I don't understand because startNotification tell me getData, but after doesn't return me callback success or callback error. How can I trouble??
this is my code:

startMeasureNotification() {
    let buffer = new ArrayBuffer(3)
    let dataViewObject = new DataView(buffer)
    dataViewObject.setUint8(0, 0x01);
    dataViewObject.setUint8(1, 0x01);
    dataViewObject.setUint8(2, 0x21);
    this.ble.startNotification(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172003-4947-11e9-8646-d663bd873d93").subscribe((result) => {
      console.log(result);
      this.ble.write(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172001-4947-11e9-8646-d663bd873d93", dataViewObject.buffer).then((result) => {


        console.log(result);

      });

    }, (error) => {
      console.log(error);
    })
    
    this.ble.startNotification(this.id2, "15172000-4947-11e9-8646-d663bd873d93", "15172003-4947-11e9-8646-d663bd873d93").subscribe((result) => {
      console.log(result);
      this.ble.write(this.id2, "15172000-4947-11e9-8646-d663bd873d93", "15172001-4947-11e9-8646-d663bd873d93", dataViewObject.buffer).then((result) => {
        console.log(result);
      });
    }, (error) => {
      console.log(error);
    });

  }

output in ios :To Native Cordova -> BLE

startNotification BLE1395621188 ["options": [B2795872-4070-B2F0-3064-1475EDA2C967, 15172000-4947-11e9-8646-d663bd873d93, 15172003-4947-11e9-8646-d663bd873d93]]
2022-06-20 12:38:25.011776+0200 App[930:122363] registering for notification
2022-06-20 12:38:25.011840+0200 App[930:122363] getData
2022-06-20 12:38:25.011933+0200 App[930:122363] Looking for 15172003-4947-11E9-8646-D663BD873D93 with properties 16

[peitschie]

The getData log there is a normal part of the startNotification flow:

cordova-plugin-ble-central/src/ios/BLECentralPlugin.m

Line 300 in 0732380

BLECommandContext *context = [self getData:command prop:CBCharacteristicPropertyNotify]; // TODO name this better

Does the Peripheral automatically start sending notifications as soon as you turn them on? Or do you need to write a payload to start them?

I ask because the ble.write you've nested in the subscribe there will only get called after a notification arrives.

[AngeNew]

I need to write payload to start them, sensors manual suggest to do before startNotification and after startMeasure, I do the ble.write inside subscribe do start of measure, Do I can try this.ble.write before startNotification??
this.ble.write(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172001-4947-11e9-8646-d663bd873d93", dataViewObject.buffer).then((result) => {
console.log(result);
this.ble.startNotification(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172003-4947-11e9-8646-d663bd873d93").subscribe((result) => {

    console.log(result);

  });

}, (error) => {
  console.log(error);
})

output: To Native Cordova -> BLE write BLE660513637 ["options": [50BDE010-2FAF-BD5D-31FD-AD391438DEB3, 15172000-4947-11e9-8646-d663bd873d93, 15172001-4947-11e9-8646-d663bd873d93, {
CDVType = ArrayBuffer;
data = AQEh;
}]]
2022-06-21 09:07:47.026710+0200 App[2549:186654] getData
2022-06-21 09:07:47.026989+0200 App[2549:186654] Looking for 15172001-4947-11E9-8646-D663BD873D93 with properties 8
To Native Cordova -> BLE startNotification BLE660513638 ["options": [50BDE010-2FAF-BD5D-31FD-AD391438DEB3, 15172000-4947-11e9-8646-d663bd873d93, 15172003-4947-11e9-8646-d663bd873d93]]
⚡️ [log] - null
2022-06-21 09:07:47.066179+0200 App[2549:186654] registering for notification
2022-06-21 09:07:47.066366+0200 App[2549:186654] getData
2022-06-21 09:07:47.066560+0200 App[2549:186654] Looking for 15172003-4947-11E9-8646-D663BD873D93 with properties 16

I haven't data, I wait your answer, thanks for your response.
in sensor in Ios, I have one flag isNotifying that is false and I read that if isNotifying is false, notification will always disable, is this my problem??

[peitschie]

Apologies @AngeNew , this fell off my radar.

Yes, I'd do the write and then subscribe. What's the console output of result there?

I'd suggest taking a look at #913 (comment) in case this is a similar display issue.

Alternatively, you might be experiencing #805 (comment)

Unfortunately, I don't maintain the ionic wrappers, so I'm not certain what's causing the problem you see there.

[AngeNew]

I trouble problem in this way, I use async await in right way, and I must convert my payload mode in hex to start correctly payload, thanks for your support

async startMeasure() {
let buffer = new ArrayBuffer(3);
let dataViewObject = new DataView(buffer);
/** 01 indicate measures /
dataViewObject.setUint8(0, 0x01);
/* 01 indicate start measures */
dataViewObject.setUint8(1, 0x01);
dataViewObject.setUint8(2, 0x15);

this.ble.startNotification(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172003-4947-11e9-8646-d663bd873d93").subscribe(
  (data) => {
    console.log(this.saveSingleMeasure(data));
    this.measures1.push(this.saveSingleMeasure(data));
  },
  () => console.log("error")
);

await this.ble.write(this.id1, "15172000-4947-11e9-8646-d663bd873d93", "15172001-4947-11e9-8646-d663bd873d93", dataViewObject.buffer).then((result) => {
  console.log(result);
}, (error) => {
  console.log(error);

});

this.ble.startNotification(this.id2, "15172000-4947-11e9-8646-d663bd873d93", "15172003-4947-11e9-8646-d663bd873d93").subscribe(
  (data) => {
    console.log(this.saveSingleMeasure(data));
    this.measures2.push(this.saveSingleMeasure(data));
  },
  () => console.log("error")
);

await this.ble.write(this.id2, "15172000-4947-11e9-8646-d663bd873d93", "15172001-4947-11e9-8646-d663bd873d93", dataViewObject.buffer).then((result) => {
  console.log(result);
}, (error) => {
  console.log(error);

});

}

I trouble also problem that send me empty notifications with this function where I use Float32 right format
for my data
/** save single measure in Float32 */
saveSingleMeasure(buffer) {
var data = new Float32Array(buffer[0]);
return data;
}