Broadcast characteristic value

I'd like to broadcast a characteristic value so it can be read from the advertising information without connecting.

Here's an Arduino example increments a counter and broadcasts the value - BroadcastCount.ino. Using nRF Connect, I can see the characteristic value. (See attached image.)

According to the docs, it looks NRF.setServices broadcast property might do this, but I can't get it to work on the Puck.js.

// Demonstrate broadcasting a characteristic value
// Use nRF Connect to see the counter value without connecting

let count = 0;

NRF.setServices({
    0xEEE0 : {
      0xEEE1 : {
        value: count,
        readable: true,
        notify: true,
        broadcast: true,
        description: 'Count'
      }
    }
  }, { advertise: [ 'EEE0' ] });

function notify() {
  NRF.updateServices({
    0xEEE0 : {
      0xEEE1 : {
        value: count,
        broadcast: true,
        notify: true
      }
    }
  });
}

setInterval(function() {
  count++;
  notify();
}, 1000);

Should broadcast update the service info or do I need to manually build this into the advertising data?

1 Attachment

You just need to use NRF.setAdvertising. There's a quick run-down of BLE and which functions in Puck.js you use for it here that might be handy: http://www.espruino.com/About+Bluetooth+LE

There's an example here that uses Manufacturerdata advertising as well that might be interesting: http://www.espruino.com/Puck.js+Advertising

@Gordon I like your nRF API. It's really easy to set the Service Data. This works great.

// Demonstrate broadcasting a characteristic value
// Use nRF Connect to see the counter value without connecting

let count = 0;

NRF.setServices({
    0xEEE0 : {
      0xEEE1 : {
        value: [0, 0],
        readable: true,
        notify: true,
        broadcast: true,
        description: 'Count'
      }
    }
  }, { advertise: [ 'EEE0' ] });

function notify() {
  const buffer = new Uint16Array([count]).buffer;
  NRF.updateServices({
    0xEEE0 : {
      0xEEE1 : {
        value: buffer,
        broadcast: true,
        notify: true
      }
    }
  });
  // Set the service data 0x16 to the count value
  NRF.setAdvertising({
    0xEEE0: buffer
  });
}

setInterval(() => {
  count++;
  if (count > 0xFFFF) {
    count = 0;
  }
  notify();
}, 1000);

1 Attachment

Great! The service data 0xCC00 looks a bit odd though.

Do you have an up to date firmware on your device? I don't see that here when I run your code.

0xCC00 is fine, I just waited 5 minutes before taking a screenshot.