20200604

README.md

@@ -31,5 +31,24 @@ Das sind die verwendeten Libraries [1]:
 | https://github.com/mcci-catena/SHT1x.git  | be7042c | Tue, 20 Sep 2011 13:56:23 +1000  |
 
 
+Patch arduino-lmic, so initial SF10 is used initially:
+
+`
+[joerg@cinnamon src]$ git diff
+diff --git a/src/lmic/lmic_bandplan_eu868.h b/src/lmic/lmic_bandplan_eu868.h
+index efff7d5..74efb37 100644
+--- a/src/lmic/lmic_bandplan_eu868.h
++++ b/src/lmic/lmic_bandplan_eu868.h
+@@ -61,7 +61,7 @@ LMICeu868_isValidBeacon1(const uint8_t *d) {
+ #undef LMICbandplan_isFSK
+ #define LMICbandplan_isFSK()    (/* RX datarate */LMIC.dndr == EU868_DR_FSK)
+ 
+-#define LMICbandplan_getInitialDrJoin() (EU868_DR_SF7)
++#define LMICbandplan_getInitialDrJoin() (EU868_DR_SF10)
+ 
+ void LMICeu868_setBcnRxParams(void);
+ #define LMICbandplan_setBcnRxParams()   LMICeu868_setBcnRxParams()
+`
+
 `[1]:
 [joerg@cinnamon libraries]$ for i in Adafruit_BME280_Library Adafruit_Sensor arduino-lmic arduino-lorawan Catena-Arduino-Platform Catena-mcciadk MCCI_FRAM_I2C Q2-HX711-Arduino-Library SparkFun_Qwiic_Scale_NAU7802_Arduino_Library OneWire SHT1x ; do cd $i; echo "| $(git remote -v |grep fetch |awk '{print $2}' |tr '\n' ' ') | $(git log --pretty=format:'%h | %cD ' -n 1) |" ; cd ..; done`

mini-beieli-node.ino

@@ -143,17 +143,10 @@ bool fFlash;
 bool fUsbPower;
 
 // have we printed the sleep info?
-bool g_fPrintedSleeping = false;
-
 //  the job that's used to synchronize us with the LMIC code
 static osjob_t iterationJob;
 static osjob_t sendJob;
 
-// the cycle time to use
-unsigned gTxCycle;
-// remaining before we reset to default
-unsigned gTxCycleCount;
-
 void setup(void)
 {
   gCatena.begin();
@@ -253,7 +246,6 @@ void setup_platform(void)
   }
 
   gLoRaWAN.SetReceiveBufferBufferCb(receiveMessage);
-  setTxCycleTime(CATCFG_T_CYCLE_INITIAL, CATCFG_INTERVAL_COUNT_INITIAL);
   gCatena.registerObject(&gLoRaWAN);
 
   /* find the platform */
@@ -348,6 +340,9 @@ void setup_uplink(void)
 
   LMIC_setClockError(1 * 65536 / 100);
 
+  // explicitly enable LinkCheckMode
+  gLoRaWAN.SetLinkCheckMode(true);
+
   /* figure out when to reboot */
   gRebootMs = (CATCFG_T_REBOOT + os_getRndU2() - 32768) * 1000;
 
@@ -677,7 +672,7 @@ void StartNewIteration() {
   // we send data the first time the system is started, when the array is full
   // or when the weight has fallen more than threshold or the first measurement is
   // more than one hour old (which should not happen :-) )
-  if ( (next_package_is_init_package) || (my_position >= MAX_VALUES_TO_SEND) || ((last_sensor_reading.weight - current_sensor_reading.weight) > SEND_DIFF_THRESHOLD_5GRAMS) || ((millis() - timer_pos0) > 3600000)) {
+  if ( (next_package_is_init_package) || (my_position >= MAX_VALUES_TO_SEND) || (abs(last_sensor_reading.weight - current_sensor_reading.weight) > SEND_DIFF_THRESHOLD_5GRAMS) || ((millis() - timer_pos0) > 3600000)) {
     lora_data.offset_last_reading = (uint8_t)((millis() - timer_pos0) / 1000 / 60);
     if (config_data.debug_level > 0) {
       gCatena.SafePrintf("startSendingUplink(), my_position: %d, iteration: %d, package_counter: %d\n", my_position, iteration, package_counter);
@@ -690,7 +685,7 @@ void StartNewIteration() {
       gLed.Set(LedPattern::TwoShort);
     }
 
-    // Loop while sending is in progress, timeout just in case after 300 seconds
+    // Loop sending is in progress, timeout just in case after 300 seconds
     long start_time = millis();
     if (config_data.debug_level > 0) {
       gCatena.SafePrintf("waiting while send is in progress\n");
@@ -700,6 +695,22 @@ void StartNewIteration() {
       gCatena.poll();
       yield();
     }
+    // handle timeout...
+    if (send_in_progress) {
+      if (config_data.debug_level > 0) {
+        gCatena.SafePrintf("looks like we timed out waiting for sending to finish...\n", wait_time);
+      }
+      LMIC_clrTxData();
+      // we sleep 10 seconds...
+      start_time = millis();
+      while ((millis() - start_time) < 10000)
+      {
+        gCatena.poll();
+        yield();
+      }
+
+      send_in_progress = false;
+    }
     wait_time = (uint32_t)((millis() - start_time) / 1000);
     if (config_data.debug_level > 0) {
       gCatena.SafePrintf("end waiting, wait time was %d seconds\n", wait_time);
@@ -719,9 +730,9 @@ void StartNewIteration() {
     sleep_time_sec = 5;
   }
 
-  // for the first <INIT_PACKETS> iterations, we set the sleep time to 10 seconds only...
+  // for the first <INIT_PACKETS> iterations, we set the sleep time to 120 seconds only...
   if (iteration <= INIT_PACKETS) {
-    sleep_time_sec = 10;
+    sleep_time_sec = 120;
   }
 
   if (config_data.debug_level > 0) {
@@ -737,25 +748,38 @@ void StartNewIteration() {
     }
   }
 
+  // if we need to periodically reboot, we can do it now...
+  if (uint32_t(millis()) > gRebootMs) {
+    // time to reboot
+    if (config_data.debug_level > 0) {
+      gCatena.SafePrintf("Reached threshold to reboot...\n");
+      Serial.flush();
+    }
+    NVIC_SystemReset();
+  }
+
+  if (config_data.debug_level > 0) {
+    gCatena.SafePrintf("LMIC.opmode just before Sleeping: %#x\n", LMIC.opmode);
+    gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
+  }
+
   if (!fUsbPower) {
     DoDeepSleep(sleep_time_sec);
     if (! stop_iterations) {
       StartNewIteration();
     }
 
-    //os_setTimedCallback(
-    //  &iterationJob,
-    //  os_getTime() + sec2osticks(2),
-    //  startNewIterationCb);
   }
   else {
-    if (config_data.debug_level > 0) {
+    if (! stop_iterations) {
-      gCatena.SafePrintf("light sleep; os_setTimedCallback for startNewIterationCb in %d...seconds\n", sleep_time_sec);
+      if (config_data.debug_level > 0) {
+        gCatena.SafePrintf("light sleep; os_setTimedCallback for startNewIterationCb in %d...seconds\n", sleep_time_sec);
+      }
+      os_setTimedCallback(
+        &iterationJob,
+        os_getTime() + sec2osticks(sleep_time_sec),
+        startNewIterationCb);
     }
-    os_setTimedCallback(
-      &iterationJob,
-      os_getTime() + sec2osticks(sleep_time_sec),
-      startNewIterationCb);
   }
 }
 
@@ -787,14 +811,33 @@ void startSendingUplink(bool firstTime)
     if (config_data.debug_level > 0) {
       gCatena.SafePrintf("SendBuffer firstTime\n");
     }
-    gLoRaWAN.SendBuffer((uint8_t*)&lora_data_first, sizeof(LORA_data_first), sendBufferDoneCb, NULL, fConfirmed, kUplinkPort);
+    if (gLoRaWAN.SendBuffer((uint8_t*)&lora_data_first, sizeof(LORA_data_first), sendBufferDoneCb, NULL, fConfirmed, kUplinkPort)) {
-    package_counter++;
+      package_counter++;
+      if (config_data.debug_level > 0) {
+        gCatena.SafePrintf("LMIC.opmode just after SendBuffer (successful): %#x\n", LMIC.opmode);
+        gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
+      }
+    }
+    else {
+      gCatena.SafePrintf("LMIC.opmode just before SendBuffer (failed): %#x\n", LMIC.opmode);
+      gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
+    }
   } else {
     if (config_data.debug_level > 0) {
+      gCatena.SafePrintf("LMIC.opmode just before SendBuffer: %#x\n", LMIC.opmode);
+      gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
       gCatena.SafePrintf("SendBuffer not firstTime\n");
     }
-    gLoRaWAN.SendBuffer((uint8_t*)&lora_data, sizeof(LORA_data), sendBufferDoneCb, NULL, fConfirmed, kUplinkPort);
+    if (gLoRaWAN.SendBuffer((uint8_t*)&lora_data, sizeof(LORA_data), sendBufferDoneCb, NULL, fConfirmed, kUplinkPort)) {
-    package_counter++;
+      package_counter++;
+      if (config_data.debug_level > 0) {
+        gCatena.SafePrintf("LMIC.opmode just after SendBuffer (successful): %#x\n", LMIC.opmode);
+        gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
+      }
+    } else {
+      gCatena.SafePrintf("LMIC.opmode just before SendBuffer (failed): %#x\n", LMIC.opmode);
+      gCatena.SafePrintf("LMIC.globalDutyRate: %d, LMIC.globalDutyAvail: %d\n", LMIC.globalDutyRate, LMIC.globalDutyAvail );
+    }
   }
 
   ClearLoraData();
@@ -808,6 +851,7 @@ static void sendBufferDoneCb(
 
   if (config_data.debug_level > 1) {
     gLed.Set(LedPattern::Settling);
+    gCatena.SafePrintf("LMIC.opmode in sendBufferDoneCb: %#x\n", LMIC.opmode);
   }
 
   pFn = settleDoneCb;
@@ -822,7 +866,7 @@ static void sendBufferDoneCb(
       gLoRaWAN.Shutdown();
     }
     else if (config_data.debug_level > 0) {
-      gCatena.SafePrintf("send buffer failed\n");
+      gCatena.SafePrintf("send buffer failed, LMIC.opmode: %#x\n", LMIC.opmode);
     }
   }
 
@@ -846,183 +890,62 @@ static void txNotProvisionedCb(
   }
 }
 
-
-static void settleDoneCb(
-  osjob_t* pSendJob)
-{
-  const bool fDeepSleep = checkDeepSleep();
-
-  if (config_data.debug_level > 0) {
-    gCatena.SafePrintf("settleDoneCb\n");
-  }
-
-  if (config_data.debug_level > 2) {
-    // Terry vv
-    gCatena.SafePrintf("LMIC.rxDelay: %i\n", LMIC.rxDelay);
-    gCatena.SafePrintf("LMIC.dn2Dr: %i\n", LMIC.dn2Dr);
-    gCatena.SafePrintf("LMIC.dn2Freq: %i\n", LMIC.dn2Freq);
-    gCatena.SafePrintf("LMIC.rx1DrOffset: %i\n", LMIC.rx1DrOffset);
-    gCatena.SafePrintf("LMIC.adrAckReq: %i\n", LMIC.adrAckReq);
-    gCatena.SafePrintf("LMIC.adrEnabled: %i\n", LMIC.adrEnabled);
-    // Terry ^^
-  }
-
-  if (uint32_t(millis()) > gRebootMs) {
-    // time to reboot
-    NVIC_SystemReset();
-  }
-
-  if (! g_fPrintedSleeping)
-    doSleepAlert(fDeepSleep);
-
-  /* count what we're up to */
-  updateSleepCounters();
-
-  if (fDeepSleep)
-    doDeepSleep(pSendJob);
-  else
-    doLightSleep(pSendJob);
-}
-
 bool checkDeepSleep(void)
 {
-  bool const fDeepSleepTest = gCatena.GetOperatingFlags() &
+  return !fUsbPower;
-                              static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fDeepSleepTest);
-  bool fDeepSleep;
-
-  if (fDeepSleepTest)
-  {
-    fDeepSleep = true;
-  }
-#ifdef USBCON
-  else if (Serial.dtr())
-  {
-    fDeepSleep = false;
-  }
-#endif
-  else if (gCatena.GetOperatingFlags() &
-           static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fDisableDeepSleep))
-  {
-    fDeepSleep = false;
-  }
-  else if ((gCatena.GetOperatingFlags() &
-            static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fUnattended)) != 0)
-  {
-    fDeepSleep = true;
-  }
-  else
-  {
-    fDeepSleep = false;
-  }
-
-  return fDeepSleep;
 }
 
 void doSleepAlert(const bool fDeepSleep)
 {
-  g_fPrintedSleeping = true;
+  if (config_data.debug_level > 0) {
+    gCatena.SafePrintf("We wait until is is safe to go to sleep...\n");
+  }
 
-  if (fDeepSleep)
+  for (int i = 0; i <= 15; i++) {
-  {
+    long prevPrint = millis();
-    bool const fDeepSleepTest = gCatena.GetOperatingFlags() &
+    while (os_queryTimeCriticalJobs(ms2osticks(2000)) != 0)
-                                static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fDeepSleepTest);
-    const uint32_t deepSleepDelay = fDeepSleepTest ? 10 : 30;
-    if (config_data.debug_level > 2) {
-      gCatena.SafePrintf("using deep sleep in %u secs"
-#ifdef USBCON
-                         " (USB will disconnect while asleep)"
-#endif
-                         ": ",
-                         deepSleepDelay
-                        );
-
-    }
-    // sleep and print
-    if (config_data.debug_level > 1) {
-      gLed.Set(LedPattern::TwoShort);
-    }
-
-    for (auto n = deepSleepDelay; n > 0; --n)
-    {
-      uint32_t tNow = millis();
-
-      while (uint32_t(millis() - tNow) < 1000)
-      {
-        gCatena.poll();
-        yield();
-      }
-      if (config_data.debug_level > 2) {
-        gCatena.SafePrintf(".");
-      }
-    }
-    if (config_data.debug_level > 2) {
-      gCatena.SafePrintf("\nStarting deep sleep.\n");
-    }
-    uint32_t tNow = millis();
-    while (uint32_t(millis() - tNow) < 100)
     {
       gCatena.poll();
       yield();
+      if (millis() - prevPrint > 1000) {
+        prevPrint = millis();
+        if (config_data.debug_level > 0) {
+          gCatena.SafePrintf("LMIC.opmode: %#x in loop %d\n", LMIC.opmode, i);
+        }
+      }
     }
   }
-  else if (config_data.debug_level > 2) {
-    gCatena.SafePrintf("using light sleep\n");
-  }
-}
-
-void updateSleepCounters(void)
-{
-  // update the sleep parameters
-  if (gTxCycleCount > 1)
-  {
-    // values greater than one are decremented and ultimately reset to default.
-    --gTxCycleCount;
-  }
-  else if (gTxCycleCount == 1)
-  {
-    // it's now one (otherwise we couldn't be here.)
-    if (config_data.debug_level > 2) {
-      gCatena.SafePrintf("resetting tx cycle to default: %u\n", CATCFG_T_CYCLE);
-    }
-
-    gTxCycleCount = 0;
-    gTxCycle = CATCFG_T_CYCLE;
-  }
-  else
-  {
-    // it's zero. Leave it alone.
-  }
-}
-
-void doDeepSleep(osjob_t *pJob)
-{
-  bool const fDeepSleepTest = gCatena.GetOperatingFlags() &
-                              static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fDeepSleepTest);
-  uint32_t const sleepInterval = CATCFG_GetInterval(
-                                   fDeepSleepTest ? CATCFG_T_CYCLE_TEST : gTxCycle
-                                 );
 
   if (config_data.debug_level > 0) {
-    gCatena.SafePrintf("doDeepSleep, sleepInterval: %d...\n", sleepInterval);
+    gCatena.SafePrintf("Now it is safe to go to sleep\n");
   }
 
-  /* ok... now it's time for a deep sleep */
+}
-  gLed.Set(LedPattern::Off);
-  deepSleepPrepare();
 
-  /* sleep */
+static void settleDoneCb(
-  gCatena.Sleep(sleepInterval);
+  osjob_t* pSendJob)
+{
+  if (config_data.debug_level > 0) {
+    gCatena.SafePrintf("settleDoneCb - we are at the end of the callback chain!\n");
+  }
 
-  /* recover from sleep */
+  const bool fDeepSleep = checkDeepSleep();
-  deepSleepRecovery();
 
-  /* and now... we're awake again. trigger another measurement */
+  if (uint32_t(millis()) > gRebootMs)
-  sleepDoneCb(pJob);
+  {
+    // time to reboot
+    NVIC_SystemReset();
+  }
+
+  doSleepAlert(fDeepSleep);
+
+  send_in_progress = false;
 }
 
 void deepSleepPrepare(void)
 {
   Serial.end();
+  Wire.endTransmission(true);
   Wire.end();
   SPI.end();
   if (fFlash)
@@ -1038,53 +961,6 @@ void deepSleepRecovery(void)
     gSPI2.begin();
 }
 
-void doLightSleep(osjob_t *pJob)
-{
-  uint32_t interval = sec2osticks(CATCFG_GetInterval(gTxCycle));
-
-
-  if (config_data.debug_level > 1) {
-    gLed.Set(LedPattern::Sleeping);
-    gCatena.SafePrintf("doLightSleep\n");
-  }
-
-  if (gCatena.GetOperatingFlags() &
-      static_cast<uint32_t>(gCatena.OPERATING_FLAGS::fQuickLightSleep))
-  {
-    interval = 1;
-  }
-
-  os_setTimedCallback(
-    &iterationJob,
-    os_getTime() + interval,
-    sleepDoneCb
-  );
-
-}
-
-static void sleepDoneCb(osjob_t* pJob)
-{
-  if (config_data.debug_level > 1) {
-    gLed.Set(LedPattern::WarmingUp);
-  }
-
-  if (config_data.debug_level > 0) {
-    gCatena.SafePrintf("sleepDoneCb\n");
-  }
-
-  os_setTimedCallback(
-    pJob,
-    os_getTime() + sec2osticks(CATCFG_T_WARMUP),
-    warmupDoneCb);
-}
-
-static void warmupDoneCb(osjob_t* pJob)
-{
-  if (config_data.debug_level > 0) {
-    gCatena.SafePrintf("warmupDoneCb\n");
-  }
-  send_in_progress = false;
-}
 
 static void startNewIterationCb(osjob_t* pJob)
 {
@@ -1099,8 +975,6 @@ static void startNewIterationCb(osjob_t* pJob)
 
 static void receiveMessage(void *pContext, uint8_t port, const uint8_t *pMessage, size_t nMessage)
 {
-  unsigned txCycle;
-  unsigned txCount;
 
   long cal_w1_0;
   long cal_w2_0;
@@ -1112,8 +986,6 @@ static void receiveMessage(void *pContext, uint8_t port, const uint8_t *pMessage
     float fval;
   } u;
 
-  SENSOR_data temp_sensor_data;
-
   if (config_data.debug_level > 0) {
     gCatena.SafePrintf("receiveMessage was called!!!\n");
   }
@@ -1218,59 +1090,8 @@ static void receiveMessage(void *pContext, uint8_t port, const uint8_t *pMessage
     }
   }
 
-  if (port == 0)
-  {
-    return;
-  }
-
-  else if (! (port == 1 && 2 <= nMessage && nMessage <= 3))
-  {
-    if (config_data.debug_level > 0) {
-      gCatena.SafePrintf("invalid message port(%02x)/length(%x)\n",
-                         port, nMessage
-                        );
-    }
-    return;
-  }
-
-  txCycle = (pMessage[0] << 8) | pMessage[1];
-
-  if (txCycle < CATCFG_T_MIN || txCycle > CATCFG_T_MAX)
-  {
-    if (config_data.debug_level > 0) {
-      gCatena.SafePrintf("tx cycle time out of range: %u\n", txCycle);
-    }
-    return;
-  }
-
-  // byte [2], if present, is the repeat count.
-  // explicitly sending zero causes it to stick.
-  txCount = CATCFG_INTERVAL_COUNT;
-  if (nMessage >= 3)
-  {
-    txCount = pMessage[2];
-  }
-
-  setTxCycleTime(txCycle, txCount);
-
 }
 
-void setTxCycleTime(unsigned txCycle, unsigned txCount)
-{
-  if (txCount > 0) {
-    if (config_data.debug_level > 0) {
-      gCatena.SafePrintf("message cycle time %u seconds for %u messages\n", txCycle, txCount);
-    }
-  }
-  else if (config_data.debug_level > 0) {
-    gCatena.SafePrintf("message cycle time %u seconds indefinitely\n", txCycle);
-  }
-
-  gTxCycle = txCycle;
-  gTxCycleCount = txCount;
-}
-
-
 /* process "application hello" -- args are ignored */
 // argv[0] is "hello"
 // argv[1..argc-1] are the (ignored) arguments

mini_beieli_node.h

@@ -56,7 +56,7 @@ enum {
   |
   \****************************************************************************/
 
-static const int32_t fwVersion = 20200525;
+static const int32_t fwVersion = 20200604;
 
 static const byte INIT_PACKAGE_INTERVAL = 100;  // send an init package every 100 packages;
 static const byte MAX_VALUES_TO_SEND = 8;
@@ -64,7 +64,7 @@ static const byte MAX_VALUES_TO_SEND = 8;
 static const uint8_t LORA_DATA_VERSION = 1;
 static const uint8_t LORA_DATA_VERSION_FIRST_PACKAGE = 128;
 static const uint32_t PRESSURE_OFFSET = 825;
-static const uint16_t SEND_DIFF_THRESHOLD_5GRAMS = 10;   // when weight value drops by 50g, then send data
+static const uint16_t SEND_DIFF_THRESHOLD_5GRAMS = 20;   // when weight changes by 100g, then send data
 static const long NOT_ATTACHED = -2147483648;
 static const byte INIT_PACKETS = 5;
 

mini_beieli_node_nau7802.h

@@ -14,7 +14,7 @@ NAU7802 myScale; //Create instance of the NAU7802 class
 
 byte debug_level;
 
-byte interruptPin = A0;
+//byte interruptPin = A0;
 
 void SetScalesDebugLevel(byte dbg_level)
 {
@@ -24,7 +24,7 @@ void SetScalesDebugLevel(byte dbg_level)
 bool InitializeScales()
 {
   bool result;
-  result &= myScale.reset(); //Reset all registers
+  result = myScale.reset(); //Reset all registers
   result &= myScale.powerUp(); //Power on analog and digital sections of the scale
 
   result &= myScale.setIntPolarityHigh();
@@ -47,7 +47,7 @@ bool SetupScales(byte dbg_level)
   if (debug_level > 0) {
     gCatena.SafePrintf("SetupScales start\n");
   }
-  pinMode(interruptPin, INPUT);
+//  pinMode(interruptPin, INPUT);
 
   if (!myScale.begin(Wire, false))
   {
@@ -96,9 +96,12 @@ long ReadScale(char channel)
   long readings[num_scale_readings];  // create arry to hold readings
   for (int i = 0; i < num_scale_readings; i++) {
     //while (digitalRead(interruptPin) == LOW) {
+    long mytimer = millis();
     while (! myScale.available()) {
-      // we set a timeout of 60 seconds for the measurement...
+      // we set a timeout of 10 seconds for the measurement...
-      if ((millis() - startTime) > 60000) {
+      if ((millis() - mytimer) > 10000) {
+        // Timeout reading scale...
+        Wire.endTransmission(true);
         if (debug_level > 0) {
           gCatena.SafePrintf("Timeout while reading scale...\n");
         }
@@ -106,11 +109,14 @@ long ReadScale(char channel)
       }
       delay(1);
     }
-    long reading = myScale.getReading();
+    long reading;
+    if (myScale.available()) {
+      reading = myScale.getReading();  
+      readings[i] = reading;  
+    }
     if (debug_level > 0) {
       gCatena.SafePrintf("Reading: %d\n", reading);
     }
-    readings[i] = reading;  // fill the array with instantaneous readings from the scale
     delay(10);
   }