diff --git a/src/extensions/scratch3_ev3/index.js b/src/extensions/scratch3_ev3/index.js
index ed47ffb5..7fa7d449 100644
--- a/src/extensions/scratch3_ev3/index.js
+++ b/src/extensions/scratch3_ev3/index.js
@@ -579,6 +579,7 @@ class EV3 {
      * Called by the runtime when user wants to disconnect from the EV3 peripheral.
      */
     disconnect () {
+        console.log('EV3 DISCONNECT');
         this._clearSensorsAndMotors();
         window.clearInterval(this._pollingIntervalID);
         this._pollingIntervalID = null;
diff --git a/src/extensions/scratch3_microbit/index.js b/src/extensions/scratch3_microbit/index.js
index b8fc2396..9392bff8 100644
--- a/src/extensions/scratch3_microbit/index.js
+++ b/src/extensions/scratch3_microbit/index.js
@@ -212,7 +212,7 @@ class MicroBit {
             filters: [
                 {services: [BLEUUID.service]}
             ]
-        }, this._onConnect, null);
+        }, this._onConnect, this.disconnect);
     }
 
     /**
@@ -229,6 +229,7 @@ class MicroBit {
      * Disconnect from the micro:bit.
      */
     disconnect () {
+        console.log('MICROBIT DISCONNECT');
         window.clearInterval(this._timeoutID);
         if (this._ble) {
             this._ble.disconnect();
@@ -317,7 +318,11 @@ class MicroBit {
 
         // cancel disconnect timeout and start a new one
         window.clearInterval(this._timeoutID);
-        this._timeoutID = window.setInterval(this.disconnect, BLETimeout);
+        this._timeoutID = window.setInterval(
+            // send an error to the BLE socket
+            this._ble._sendDisconnectError.bind(this._ble, 'micro:bit stopped receiving data'),
+            BLETimeout
+        );
     }
 
     /**
diff --git a/src/extensions/scratch3_wedo2/index.js b/src/extensions/scratch3_wedo2/index.js
index 3edb8784..8ea69c8b 100644
--- a/src/extensions/scratch3_wedo2/index.js
+++ b/src/extensions/scratch3_wedo2/index.js
@@ -611,6 +611,7 @@ class WeDo2 {
      * Disconnects from the current BLE socket.
      */
     disconnect () {
+        console.log('WEDO2 DISCONNECT');
         this._ports = ['none', 'none'];
         this._motors = [null, null];
         this._sensors = {
diff --git a/src/io/ble.js b/src/io/ble.js
index afe384a7..ce493020 100644
--- a/src/io/ble.js
+++ b/src/io/ble.js
@@ -73,7 +73,10 @@ class BLE extends JSONRPCWebSocket {
      * Close the websocket.
      */
     disconnect () {
+        if (!this._connected) return;
+
         this._ws.close();
+        this._connected = false;
         if (this._discoverTimeoutID) {
             window.clearTimeout(this._discoverTimeoutID);
         }
@@ -191,9 +194,10 @@ class BLE extends JSONRPCWebSocket {
 
         if (!this._connected) return;
 
-        this._connected = false;
         if (this._disconnectCallback) {
-            this._disconnectCallback();
+            this._disconnectCallback(); // will trigger a disconnect()
+        } else {
+            this.disconnect();
         }
 
         this._runtime.emit(this._runtime.constructor.PERIPHERAL_DISCONNECT_ERROR, {
diff --git a/src/io/bt.js b/src/io/bt.js
index bf393f76..356e04ee 100644
--- a/src/io/bt.js
+++ b/src/io/bt.js
@@ -75,7 +75,10 @@ class BT extends JSONRPCWebSocket {
      * Close the websocket.
      */
     disconnect () {
+        if (!this._connected) return;
+
         this._ws.close();
+        this._connected = false;
         if (this._discoverTimeoutID) {
             window.clearTimeout(this._discoverTimeoutID);
         }
@@ -136,9 +139,10 @@ class BT extends JSONRPCWebSocket {
 
         if (!this._connected) return;
 
-        this._connected = false;
         if (this._disconnectCallback) {
-            this._disconnectCallback();
+            this._disconnectCallback(); // will trigger a disconnect()
+        } else {
+            this.disconnect();
         }
 
         this._runtime.emit(this._runtime.constructor.PERIPHERAL_DISCONNECT_ERROR, {