WeDo2 Extension: First Pass (#1441)

* Adding WeDo2 connection/disconnection over Scratch Link BLE.

* Testing motor and LED output.

* Reading sensor attachment and registering for sensor notifications.

* Motor indexing.

* Some refactoring notes.  Moving some functions around.

* Refactoring and enums.

* Removing some comments

* Fixing linting error.

* Fixing tilt reporter values and added stopAll bound to stop button to stop piezo, LED and motors.

src/extensions/scratch3_wedo2/index.js

@@ -2,6 +2,8 @@ const ArgumentType = require('../../extension-support/argument-type');
 const BlockType = require('../../extension-support/block-type');
 const color = require('../../util/color');
 const log = require('../../util/log');
+const BLESession = require('../../io/bleSession');
+const Base64Util = require('../../util/base64-util');
 
 /**
  * Icon svg to be displayed at the left edge of each extension block, encoded as a data URI.
@@ -10,6 +12,51 @@ const log = require('../../util/log');
 // eslint-disable-next-line max-len
 const iconURI = 'data:image/svg+xml;base64,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';
 
+const UUID = {
+    DEVICE_SERVICE: '00001523-1212-efde-1523-785feabcd123',
+    IO_SERVICE: '00004f0e-1212-efde-1523-785feabcd123',
+    ATTACHED_IO: '00001527-1212-efde-1523-785feabcd123',
+    INPUT_VALUES: '00001560-1212-efde-1523-785feabcd123',
+    INPUT_COMMAND: '00001563-1212-efde-1523-785feabcd123',
+    OUTPUT_COMMAND: '00001565-1212-efde-1523-785feabcd123'
+};
+
+/**
+ * Enum for WeDo2 sensor and output types.
+ * @readonly
+ * @enum {number}
+ */
+const WeDo2Types = {
+    MOTOR: 1,
+    PIEZO: 22,
+    LED: 23,
+    TILT: 34,
+    DISTANCE: 35
+};
+
+/**
+ * Enum for connection/port ids assigned to internal WeDo2 output devices.
+ * @readonly
+ * @enum {number}
+ */
+const WeDo2ConnectIDs = {
+    LED: 6,
+    PIEZO: 5
+};
+
+/**
+ * Enum for ids for various output commands on the WeDo2.
+ * @readonly
+ * @enum {number}
+ */
+const WeDo2Commands = {
+    MOTOR_POWER: 1,
+    PLAY_TONE: 2,
+    STOP_TONE: 3,
+    WRITE_RGB: 4,
+    SET_VOLUME: 255
+};
+
 /**
  * Manage power, direction, and timers for one WeDo 2.0 motor.
  */
@@ -118,7 +165,14 @@ class WeDo2Motor {
      * Turn this motor on indefinitely.
      */
     setMotorOn () {
-        this._parent._send('motorOn', {motorIndex: this._index, power: this._direction * this._power});
+        const cmd = new Uint8Array(4);
+        cmd[0] = this._index + 1; // connect id
+        cmd[1] = WeDo2Commands.MOTOR_POWER; // command
+        cmd[2] = 1; // 1 byte to follow
+        cmd[3] = this._power * this._direction; // power in range 0-100
+
+        this._parent._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+
         this._isOn = true;
         this._clearTimeout();
     }
@@ -137,7 +191,14 @@ class WeDo2Motor {
      * Start active braking on this motor. After a short time, the motor will turn off.
      */
     startBraking () {
-        this._parent._send('motorBrake', {motorIndex: this._index});
+        const cmd = new Uint8Array(4);
+        cmd[0] = this._index + 1; // connect id
+        cmd[1] = WeDo2Commands.MOTOR_POWER; // command
+        cmd[2] = 1; // 1 byte to follow
+        cmd[3] = 127; // power in range 0-100
+
+        this._parent._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+
         this._isOn = false;
         this._setNewTimeout(this.setMotorOff, WeDo2Motor.BRAKE_TIME_MS);
     }
@@ -146,7 +207,14 @@ class WeDo2Motor {
      * Turn this motor off.
      */
     setMotorOff () {
-        this._parent._send('motorOff', {motorIndex: this._index});
+        const cmd = new Uint8Array(4);
+        cmd[0] = this._index + 1; // connect id
+        cmd[1] = WeDo2Commands.MOTOR_POWER; // command
+        cmd[2] = 1; // 1 byte to follow
+        cmd[3] = 0; // power in range 0-100
+
+        this._parent._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+
         this._isOn = false;
     }
 
@@ -180,35 +248,33 @@ class WeDo2Motor {
 }
 
 /**
- * Manage communication with a WeDo 2.0 device over a Device Manager client socket.
+ * Manage communication with a WeDo 2.0 device over a Bluetooth Low Energy client socket.
  */
 class WeDo2 {
 
-    /**
+    constructor (runtime, extensionId) {
-     * @return {string} - the type of Device Manager device socket that this class will handle.
-     */
-    static get DEVICE_TYPE () {
-        return 'wedo2';
-    }
 
-    /**
-     * Construct a WeDo2 communication object.
-     * @param {Socket} socket - the socket for a WeDo 2.0 device, as provided by a Device Manager client.
-     */
-    constructor (socket) {
         /**
-         * The socket-IO socket used to communicate with the Device Manager about this device.
+         * The Scratch 3.0 runtime used to trigger the green flag button.
-         * @type {Socket}
+         * @type {Runtime}
          * @private
          */
-        this._socket = socket;
+        this._runtime = runtime;
+        this._runtime.on('PROJECT_STOP_ALL', this._stopAll.bind(this));
+
+        /**
+         * The device ports that connect to motors and sensors.
+         * @type {string[]}
+         * @private
+         */
+        this._ports = ['none', 'none']; // TODO: rename?
 
         /**
          * The motors which this WeDo 2.0 could possibly have.
          * @type {WeDo2Motor[]}
          * @private
          */
-        this._motors = [new WeDo2Motor(this, 0), new WeDo2Motor(this, 1)];
+        this._motors = [null, null];
 
         /**
          * The most recently received value for each sensor.
@@ -221,17 +287,16 @@ class WeDo2 {
             distance: 0
         };
 
-        this._onSensorChanged = this._onSensorChanged.bind(this);
+        /**
-        this._onDisconnect = this._onDisconnect.bind(this);
+         * The Bluetooth connection session for reading/writing device data.
+         * @type {BLESession}
+         * @private
+         */
+        this._ble = null;
+        this._runtime.registerExtensionDevice(extensionId, this);
 
-        this._connectEvents();
+        this._onConnect = this._onConnect.bind(this);
-    }
+        this._onMessage = this._onMessage.bind(this);
-
-    /**
-     * Manually dispose of this object.
-     */
-    dispose () {
-        this._disconnectEvents();
     }
 
     /**
@@ -252,7 +317,7 @@ class WeDo2 {
      * @return {number} - the latest value received from the distance sensor.
      */
     get distance () {
-        return this._sensors.distance * 10;
+        return this._sensors.distance;
     }
 
     /**
@@ -264,12 +329,46 @@ class WeDo2 {
         return this._motors[index];
     }
 
+    /**
+     * Stop all the motors that are currently running.
+     */
+    stopAllMotors () {
+        this._motors.forEach(motor => {
+            if (motor && motor.isOn) {
+                motor.setMotorOff();
+            }
+        });
+    }
+
     /**
      * Set the WeDo 2.0 hub's LED to a specific color.
      * @param {int} rgb - a 24-bit RGB color in 0xRRGGBB format.
      */
     setLED (rgb) {
-        this._send('setLED', {rgb});
+        const cmd = new Uint8Array(6);
+        cmd[0] = WeDo2ConnectIDs.LED; // connect id
+        cmd[1] = WeDo2Commands.WRITE_RGB; // command
+        cmd[2] = 3; // 3 bytes to follow
+        cmd[3] = (rgb >> 16) & 0x000000FF;
+        cmd[4] = (rgb >> 8) & 0x000000FF;
+        cmd[5] = (rgb) & 0x000000FF;
+
+        this._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+    }
+
+    /**
+     * Switch off the LED on the WeDo2.
+     */
+    stopLED () {
+        const cmd = new Uint8Array(6);
+        cmd[0] = WeDo2ConnectIDs.LED; // connect id
+        cmd[1] = WeDo2Commands.WRITE_RGB; // command
+        cmd[2] = 3; // 3 bytes to follow
+        cmd[3] = 0x000000; // off
+        cmd[4] = 0x000000;
+        cmd[5] = 0x000000;
+
+        this._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
     }
 
     /**
@@ -278,63 +377,237 @@ class WeDo2 {
      * @param {int} milliseconds - the duration of the note, in milliseconds.
      */
     playTone (tone, milliseconds) {
-        this._send('playTone', {tone, ms: milliseconds});
+        const cmd = new Uint8Array(7);
+        cmd[0] = WeDo2ConnectIDs.PIEZO; // connect id
+        cmd[1] = WeDo2Commands.PLAY_TONE; // command
+        cmd[2] = 4; // 4 bytes to follow
+        cmd[3] = tone;
+        cmd[4] = tone >> 8;
+        cmd[5] = milliseconds;
+        cmd[6] = milliseconds >> 8;
+
+        this._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
     }
 
     /**
      * Stop the tone playing from the WeDo 2.0 hub, if any.
      */
     stopTone () {
-        this._send('stopTone');
+        const cmd = new Uint8Array(2);
+        cmd[0] = WeDo2ConnectIDs.PIEZO; // connect id
+        cmd[1] = WeDo2Commands.STOP_TONE; // command
+
+        this._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
     }
 
     /**
-     * Attach event handlers to the device socket.
+     * Called by the runtime when user wants to scan for a device.
-     * @private
      */
-    _connectEvents () {
+    // TODO: rename scan?
-        this._socket.on('sensorChanged', this._onSensorChanged);
+    startDeviceScan () {
-        this._socket.on('deviceWasClosed', this._onDisconnect);
+        this._ble = new BLESession(this._runtime, {
-        this._socket.on('disconnect', this._onDisconnect);
+            filters: [{services: [UUID.DEVICE_SERVICE]}],
+            optionalServices: [UUID.IO_SERVICE]
+        }, this._onConnect);
     }
 
     /**
-     * Detach event handlers from the device socket.
+     * Called by the runtime when user wants to connect to a certain device.
-     * @private
+     * @param {number} id - the id of the device to connect to.
      */
-    _disconnectEvents () {
+    // TODO: rename connect?
-        this._socket.off('sensorChanged', this._onSensorChanged);
+    connectDevice (id) {
-        this._socket.off('deviceWasClosed', this._onDisconnect);
+        this._ble.connectDevice(id);
-        this._socket.off('disconnect', this._onDisconnect);
     }
 
     /**
-     * Store the sensor value from an incoming 'sensorChanged' event.
+     * Disconnects from the current BLE session.
-     * @param {object} event - the 'sensorChanged' event.
-     * @property {string} sensorName - the name of the sensor which changed.
-     * @property {number} sensorValue - the new value of the sensor.
-     * @private
      */
-    _onSensorChanged (event) {
+    // TODO: rename disconnect?
-        this._sensors[event.sensorName] = event.sensorValue;
+    disconnectSession () {
+        // window.clearInterval(this._timeoutID);
+        this._ble.disconnectSession();
     }
 
     /**
-     * React to device disconnection. May be called more than once.
+     * Called by the runtime to detect whether the device is connected.
-     * @private
+     * @return {boolean} - the connected state.
      */
-    _onDisconnect () {
+    // TODO: rename isConnected
-        this._disconnectEvents();
+    getPeripheralIsConnected () {
+        let connected = false;
+        if (this._ble) {
+            connected = this._ble.getPeripheralIsConnected();
+        }
+        return connected;
     }
 
     /**
-     * Send a message to the device socket.
+     * Sets LED mode and starts reading data from device after BLE has connected.
-     * @param {string} message - the name of the message, such as 'playTone'.
-     * @param {object} [details] - optional additional details for the message, such as tone duration and pitch.
      * @private
      */
-    _send (message, details) {
+    _onConnect () {
-        this._socket.emit(message, details);
+        // set LED input mode to RGB
+        this._setLEDMode()
+            .then(() => {
+                // register for attached io notifications
+                this._ble.read(UUID.DEVICE_SERVICE, UUID.ATTACHED_IO, true, this._onMessage);
+            });
+
+        // this._setVolume();
+    }
+
+    /**
+     * Process the sensor data from the incoming BLE characteristic.
+     * @param {object} base64 - the incoming BLE data.
+     * @private
+     */
+    _onMessage (base64) {
+        const data = Base64Util.base64ToUint8Array(base64);
+        // log.info(data);
+
+        if (data.length === 2) { // disconnect sensor
+            const connectID = data[0];
+            // zero out tilt
+            if (this._ports[connectID - 1] === WeDo2Types.TILT) {
+                this._sensors.tiltX = this._sensors.tiltY = 0;
+            }
+            // zero out distance
+            if (this._ports[connectID - 1] === WeDo2Types.DISTANCE) {
+                this._sensors.distance = 0;
+            }
+            // remove references to ports and motors
+            if (connectID === 1 || connectID === 2) {
+                this._ports[connectID - 1] = 'none';
+                this._motors[connectID - 1] = null;
+                // log.info(`this._ports = ${this._ports}`);
+                // log.info(`this._motors = ${this._mtors}`);
+            }
+        }
+
+        if (data.length === 3) { // distance sensor value?
+            this._sensors.distance = data[2];
+        }
+
+        if (data.length === 4) { // tilt sensor value?
+            this._sensors.tiltX = data[2];
+            this._sensors.tiltY = data[3];
+        }
+
+        if (data.length === 12) { // attached io?
+
+            const connectID = data[0];
+            const type = data[3];
+
+            // Record which port is connected to what type of device
+            if (connectID === 1 || connectID === 2) {
+                this._ports[connectID - 1] = type;
+            }
+
+            // Motor
+            if (type === WeDo2Types.MOTOR) {
+                this._motors[connectID - 1] = new WeDo2Motor(this, connectID - 1);
+            }
+
+            // Tilt Sensor
+            if (type === WeDo2Types.TILT) {
+                const cmd = new Uint8Array(11);
+                cmd[0] = 1; // sensor format
+                cmd[1] = 2; // command type: write
+                cmd[2] = connectID; // connect id
+                cmd[3] = WeDo2Types.TILT; // type
+                cmd[4] = 0; // mode: angle
+                cmd[5] = 1; // delta interval, 4 bytes
+                cmd[6] = 0;
+                cmd[7] = 0;
+                cmd[8] = 0;
+                cmd[9] = 0; // unit?
+                cmd[10] = 1; // notifications enabled: true
+
+                this._send(UUID.INPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd))
+                    .then(() => {
+                        this._ble.read(UUID.IO_SERVICE, UUID.INPUT_VALUES, true, this._onMessage.bind(this));
+                    });
+            }
+
+            // Distance Sensor
+            if (type === WeDo2Types.DISTANCE) {
+                const cmd = new Uint8Array(11);
+                cmd[0] = 1; // sensor format
+                cmd[1] = 2; // command type: write
+                cmd[2] = connectID; // connect id
+                cmd[3] = WeDo2Types.DISTANCE; // type
+                cmd[4] = 0; // mode: detect
+                cmd[5] = 1; // delta interval, 4 bytes
+                cmd[6] = 0;
+                cmd[7] = 0;
+                cmd[8] = 0;
+                cmd[9] = 0; // unit: ?
+                cmd[10] = 1; // notifications enabled: true
+
+                this._send(UUID.INPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd))
+                    .then(() => {
+                        this._ble.read(UUID.IO_SERVICE, UUID.INPUT_VALUES, true, this._onMessage.bind(this));
+                    });
+            }
+        }
+    }
+
+    /**
+     * Write a message to the device BLE session.
+     * @param {number} uuid - the UUID of the characteristic to write to
+     * @param {Uint8Array} message - the message to write.
+     * @return {Promise} - a promise result of the write operation
+     * @private
+     */
+    _send (uuid, message) {
+        if (!this.getPeripheralIsConnected()) return;
+        return this._ble.write(UUID.IO_SERVICE, uuid, message, 'base64');
+    }
+
+    /**
+     * Sets the volume for the piezo.
+     * @private
+     */
+    _setVolume () {
+        const cmd = new Uint8Array(4);
+        cmd[0] = WeDo2ConnectIDs.PIEZO; // connect id
+        cmd[1] = WeDo2Commands.SET_VOLUME; // command
+        cmd[2] = 1; // 1 byte to follow
+        cmd[3] = 100; // volume in range 0-100
+
+        this._send(UUID.OUTPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+    }
+
+    /**
+     * Sets the input mode of the LED to RGB.
+     * @return {Promise} - a promise returned by the send operation.
+     * @private
+     */
+    _setLEDMode () {
+        const cmd = new Uint8Array(11);
+        cmd[0] = 1; // sensor format
+        cmd[1] = 2; // command type: 2 = write
+        cmd[2] = WeDo2ConnectIDs.LED; // port
+        cmd[3] = WeDo2Types.LED; // type
+        cmd[4] = 1; // mode
+        cmd[5] = 0; // delta interval, 4 bytes
+        cmd[6] = 0;
+        cmd[7] = 0;
+        cmd[8] = 0;
+        cmd[9] = 0; // unit = raw
+        cmd[10] = 0; // notifications enabled: false
+
+        return this._send(UUID.INPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd));
+    }
+
+    /**
+     * Stop the tone playing, LED output and motors on the WeDo 2.0 hub.
+     */
+    _stopAll () {
+        this.stopTone();
+        this.stopAllMotors();
+        this.stopLED();
     }
 }
 
@@ -404,7 +677,8 @@ class Scratch3WeDo2Blocks {
          */
         this.runtime = runtime;
 
-        this.connect();
+        // Create a new WeDo2 device instance
+        this._device = new WeDo2(this.runtime, Scratch3WeDo2Blocks.EXTENSION_ID);
     }
 
     /**
@@ -415,6 +689,7 @@ class Scratch3WeDo2Blocks {
             id: Scratch3WeDo2Blocks.EXTENSION_ID,
             name: 'WeDo 2.0',
             iconURI: iconURI,
+            showStatusButton: true,
             blocks: [
                 {
                     opcode: 'motorOnFor',
@@ -585,35 +860,6 @@ class Scratch3WeDo2Blocks {
         };
     }
 
-    /**
-     * Use the Device Manager client to attempt to connect to a WeDo 2.0 device.
-     */
-    connect () {
-        if (this._device || this._finder) {
-            return;
-        }
-        const deviceManager = this.runtime.ioDevices.deviceManager;
-        const finder = this._finder =
-            deviceManager.searchAndConnect(Scratch3WeDo2Blocks.EXTENSION_ID, WeDo2.DEVICE_TYPE);
-        this._finder.promise.then(
-            socket => {
-                if (this._finder === finder) {
-                    this._finder = null;
-                    this._device = new WeDo2(socket);
-                } else {
-                    log.warn('Ignoring success from stale WeDo 2.0 connection attempt');
-                }
-            },
-            reason => {
-                if (this._finder === finder) {
-                    this._finder = null;
-                    log.warn(`WeDo 2.0 connection failed: ${reason}`);
-                } else {
-                    log.warn('Ignoring failure from stale WeDo 2.0 connection attempt');
-                }
-            });
-    }
-
     /**
      * Turn specified motor(s) on for a specified duration.
      * @param {object} args - the block's arguments.
@@ -625,7 +871,10 @@ class Scratch3WeDo2Blocks {
         const durationMS = args.DURATION * 1000;
         return new Promise(resolve => {
             this._forEachMotor(args.MOTOR_ID, motorIndex => {
-                this._device.motor(motorIndex).setMotorOnFor(durationMS);
+                const motor = this._device.motor(motorIndex);
+                if (motor) {
+                    motor.setMotorOnFor(durationMS);
+                }
             });
 
             // Ensure this block runs for a fixed amount of time even when no device is connected.
@@ -640,7 +889,10 @@ class Scratch3WeDo2Blocks {
      */
     motorOn (args) {
         this._forEachMotor(args.MOTOR_ID, motorIndex => {
-            this._device.motor(motorIndex).setMotorOn();
+            const motor = this._device.motor(motorIndex);
+            if (motor) {
+                motor.setMotorOn();
+            }
         });
     }
 
@@ -651,7 +903,10 @@ class Scratch3WeDo2Blocks {
      */
     motorOff (args) {
         this._forEachMotor(args.MOTOR_ID, motorIndex => {
-            this._device.motor(motorIndex).setMotorOff();
+            const motor = this._device.motor(motorIndex);
+            if (motor) {
+                motor.setMotorOff();
+            }
         });
     }
 
@@ -664,8 +919,10 @@ class Scratch3WeDo2Blocks {
     startMotorPower (args) {
         this._forEachMotor(args.MOTOR_ID, motorIndex => {
             const motor = this._device.motor(motorIndex);
-            motor.power = args.POWER;
+            if (motor) {
-            motor.setMotorOn();
+                motor.power = args.POWER;
+                motor.setMotorOn();
+            }
         });
     }
 
@@ -679,19 +936,21 @@ class Scratch3WeDo2Blocks {
     setMotorDirection (args) {
         this._forEachMotor(args.MOTOR_ID, motorIndex => {
             const motor = this._device.motor(motorIndex);
-            switch (args.DIRECTION) {
+            if (motor) {
-            case MotorDirection.FORWARD:
+                switch (args.DIRECTION) {
-                motor.direction = 1;
+                case MotorDirection.FORWARD:
-                break;
+                    motor.direction = 1;
-            case MotorDirection.BACKWARD:
+                    break;
-                motor.direction = -1;
+                case MotorDirection.BACKWARD:
-                break;
+                    motor.direction = -1;
-            case MotorDirection.REVERSE:
+                    break;
-                motor.direction = -motor.direction;
+                case MotorDirection.REVERSE:
-                break;
+                    motor.direction = -motor.direction;
-            default:
+                    break;
-                log.warn(`Unknown motor direction in setMotorDirection: ${args.DIRECTION}`);
+                default:
-                break;
+                    log.warn(`Unknown motor direction in setMotorDirection: ${args.DIRECTION}`);
+                    break;
+                }
             }
         });
     }
@@ -813,13 +1072,13 @@ class Scratch3WeDo2Blocks {
     _getTiltAngle (direction) {
         switch (direction) {
         case TiltDirection.UP:
-            return -this._device.tiltY;
+            return this._device.tiltY > 45 ? 256 - this._device.tiltY : -this._device.tiltY;
         case TiltDirection.DOWN:
-            return this._device.tiltY;
+            return this._device.tiltY > 45 ? this._device.tiltY - 256 : this._device.tiltY;
         case TiltDirection.LEFT:
-            return -this._device.tiltX;
+            return this._device.tiltX > 45 ? 256 - this._device.tiltX : -this._device.tiltX;
         case TiltDirection.RIGHT:
-            return this._device.tiltX;
+            return this._device.tiltX > 45 ? this._device.tiltX - 256 : this._device.tiltX;
         default:
             log.warn(`Unknown tilt direction in _getTiltAngle: ${direction}`);
         }

src/io/bleSession.js

@@ -1,5 +1,5 @@
 const JSONRPCWebSocket = require('../util/jsonrpc-web-socket');
-// const log = require('../util/log');
+const log = require('../util/log');
 const ScratchLinkWebSocket = 'wss://device-manager.scratch.mit.edu:20110/scratch/ble';
 
 class BLESession extends JSONRPCWebSocket {
@@ -121,7 +121,9 @@ class BLESession extends JSONRPCWebSocket {
         this._characteristicDidChangeCallback = onCharacteristicChanged;
         return this.sendRemoteRequest('read', params)
             .catch(e => {
-                this._sendError(e);
+                if (e.data !== 'Reading is not permitted.') { // TODO: workaround til notify-only supported
+                    this._sendError(e);
+                }
             });
     }
 
@@ -144,9 +146,9 @@ class BLESession extends JSONRPCWebSocket {
             });
     }
 
-    _sendError (/* e */) {
+    _sendError (e) {
         this._connected = false;
-        // log.error(`BLESession error: ${JSON.stringify(e)}`);
+        log.error(`BLESession error: ${JSON.stringify(e)}`);
         this._runtime.emit(this._runtime.constructor.PERIPHERAL_ERROR);
     }