Index: sources/bluetooth/BLEScanner.cpp
===================================================================
diff -u -r666594860f4ea32da9a2bd362d40325b881b11f9 -r3a238930f8d939800512c9a786e96f15b35a2001
--- sources/bluetooth/BLEScanner.cpp	(.../BLEScanner.cpp)	(revision 666594860f4ea32da9a2bd362d40325b881b11f9)
+++ sources/bluetooth/BLEScanner.cpp	(.../BLEScanner.cpp)	(revision 3a238930f8d939800512c9a786e96f15b35a2001)
@@ -146,6 +146,7 @@
  */
 void BLEScanner::doScanForDevices()
 {
+    timer->stop();
     discoveryAgent->start();
 }
 
@@ -194,6 +195,9 @@
  */
 void BLEScanner::onRequestDeviceSerialNumber()
 {
+    if (omronDeviceInformationService == nullptr)
+        return;
+
     // read device serial number
     const QLowEnergyCharacteristic c = omronDeviceInformationService->characteristic(
                 QBluetoothUuid(QBluetoothUuid::SerialNumberString)
@@ -439,7 +443,7 @@
 /*!
  * \brief BLEScanner::updateBLECuffCheckinType
  * Toggles the type of check we do with the BLE cuff.
- * If already connected, just query it repeatedly ever 1Hz.
+ * If already connected, just query it repeatedly every 1Hz.
  * Otherwise, start trying to reconnect to it.
  * \param retryConnection - if true, retry connection, normal checkin otherwise.
  */