Detect when a puck.js disconnects from a browser form

[espruino-discuss]

Posted at 2021-09-08 by Jeff

Hello all,

I am a newbie and appreciate any help. I have tried generating a solution but have lost much hair trying!

I connect to the puck from a Windows browser using the following javascript function and query the accelerometer with a timer using the subsequent function. How can I detect if the puck.js disconnects?

Thanks in advance,

Jeff

// When we click the connect button...
    function connectclick() {
      Puck.write('Puck.accelOn(1.6);\n');
      Puck.write('NRF.setTxPower(4);\n');
      acceltimer = setInterval(accelcollect,650);
    }

    function accelcollect() {
      Puck.eval("Puck.accel()",function(x) {
        //Get accel data
        accel.x=x.acc.x;
        accel.y=x.acc.y;
        accel.z=x.acc.z;       
      })
    }

[espruino-discuss]

Posted at 2021-09-08 by Robin

Wed 2021.09.08

Hi @jeff   One idea might be to have the Puck regularly signal the web page, and have the web page continually look for that 'ping'. Within a try/catch block, when the ping doesn't arrive timely, throw and trap an exception within the web page itself.

Example bi-directional comm examples here:

https://www.espruino.com/Web%20Bluetooth
https://www.puck-js.com/go

---

Posted at 2021-09-12 by Jeff

Thanks for the information Robin. I will look into a try/catch block.

Rather than looking for an error is could I query the BLE and make use of the following information the puck sends?

Sorry if this is total newby question.

puck.js:406 Connected
puck.js:406 SEND ERROR: NotSupportedError: GATT operation failed for unknown reason.
puck.js:406 Disconnected (gattserverdisconnected)

---

Posted at 2021-09-12 by Robin

Sun 2021.09.12

Hi @jeff as I indicated 'One idea might be to have the Puck regularly signal' and you now have yet another.

I steered away from that solution as I wasn't able to find a suitable example/tutorial and there had been a recent post on how to wire the rejected 'Promise' into existing code.

http://forum.espruino.com/conversations/367683/

http://www.espruino.com/Reference#BluetoothRemoteGATTService

Anyone suggest/provide a simple example code block, other than the API reference?

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Posted at 2021-09-14 by @gfwilliams

Hi - those errors actually come from the puck.js library on the PC.

I think the easiest way to check for connection is to use Puck.isConnected(). I believe Puck.getConnection().on('close', function() { console.log("connection closed!") }); will work too - but to need to do that after you connected the first time

The Puck library isn't that well documented externally, but there are a bunch of comments inside it that might help: https://github.com/espruino/EspruinoWebTools/blob/master/puck.js#L446