Web Bluetooth UART Terminal

RWB · July 20, 2019, 3:52am

I came across a webpage based Bluetooth Low Energy Serial Terminal that you can use with the Gen3 Devices when you enable Bluetooth using @rickkas7 latest BLE Serial UART Library.

This makes it really easy to open up a quick Serial Terminal on your phone, tablet, or Laptop computer to see what your Gen3 Device is spitting out.

This one by nRF works perfectly for finding Gen3 Devices when you’re using Ricks BLE Serial UART example code. It’s basically a Web Based CLI for Nordic devices but I just test it to see the Serial Data stream.

https://wiki.makerdiary.com/web-device-cli/

Here is a very clean web based BLE serial terminal which I like better but it requires the Gen3 Device to be configured differently so it’s broadcasting a different characteristic

https://loginov.rocks/Web-Bluetooth-Terminal/

@rickkas7 What needs to be changed to get the 2nd cleaner version of the web serial app to work like the first nRF version does? Or can you just change the code on the 2nd example to look for the same BLE services that the nRF web Cli version does?

I think this is very cool stuff since it does not requre any applications to be installed.

ScruffR · July 21, 2019, 11:54am

Or you adapt the Web Termnial to scan for a different service/characteristic
These are only the defaults

github.com

loginov-rocks/Web-Bluetooth-Terminal/blob/dev/js/BluetoothTerminal.js#L12


      
          * Bluetooth Terminal class.
          */
          class BluetoothTerminal {
           /**
            * Create preconfigured Bluetooth Terminal instance.
            * @param {!(number|string)} [serviceUuid=0xFFE0] - Service UUID
            * @param {!(number|string)} [characteristicUuid=0xFFE1] - Characteristic UUID
            * @param {string} [receiveSeparator='\n'] - Receive separator
            * @param {string} [sendSeparator='\n'] - Send separator
            */
           constructor(serviceUuid = 0xFFE0, characteristicUuid = 0xFFE1,
               receiveSeparator = '\n', sendSeparator = '\n') {
             // Used private variables.
             this._receiveBuffer = ''; // Buffer containing not separated data.
             this._maxCharacteristicValueLength = 20; // Max characteristic value length.
             this._device = null; // Device object cache.
             this._characteristic = null; // Characteristic object cache.
          
             // Bound functions used to add and remove appropriate event handlers.
             this._boundHandleDisconnection = this._handleDisconnection.bind(this);
             this._boundHandleCharacteristicValueChanged =

So when you see a call like let terminal = new BluetoothTerminal(); you'd just add the wanted serviceUuid and characteristicUuid as needed in the parameter list instead of relying on the defaults.

Apart from a browser that's Bluetooth Web API enabled - since that's what this library utilises.

RWB · July 21, 2019, 4:01pm

Sweet! Looks like changing the UUID data and uploading to a server would allow the default Serial UART characteristics to show up just fine. I'll have to give that a shot.

It looks like a lot of the Arduino BLE devices are using the UUID's below for serial TX & RX and that's why they are programmed as the default UUID's for these web-based serial terminals?

@rickkas7 @ScruffR In Ricks BLE Serial library are we using nRF's default UUID's for BLE Serial UART which happens to be different than the default TX & RX non Nordic nRF BLE device UUID's?

I'm wondering what the differences are here between the UUID's? Any thoughts on this?

serviceUuid = 0xFFE0, characteristicUuid = 0xFFE1,

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Web Bluetooth UART Terminal

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