From a97afbf36c23385684a6ea6852d2c5c4460a6e07 Mon Sep 17 00:00:00 2001
From: Joerg Lehmann <joerg.lehmann@nbit.ch>
Date: Fri, 12 Jul 2019 21:17:11 +0200
Subject: [PATCH] refactor read sensors

---
 mini-beieli-node.ino | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/mini-beieli-node.ino b/mini-beieli-node.ino
index bdc1086..5079310 100644
--- a/mini-beieli-node.ino
+++ b/mini-beieli-node.ino
@@ -15,6 +15,7 @@
 #include <Catena_Mx25v8035f.h>
 
 #include <Wire.h>
+#include <Adafruit_Sensor.h>
 #include <Adafruit_BME280.h>
 #include <Arduino_LoRaWAN.h>
 #include <lmic.h>
@@ -135,6 +136,7 @@ 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
 
 /****************************************************************************\
   |
@@ -467,6 +469,15 @@ void ClearLoraData(void)
   lora_data_first.temperature = 0;
 
   my_position = 0;
+
+  // We initialize last_sensor_reading
+  last_sensor_reading.vbat = 0;
+  last_sensor_reading.weight1 = 0;
+  last_sensor_reading.weight2 = 0;
+  last_sensor_reading.weight = 0;
+  last_sensor_reading.temperature = 0;
+  last_sensor_reading.humidity = 0;
+  last_sensor_reading.pressure = 0;
 }
 
 void ShowLORAData(bool firstTime)
@@ -577,11 +588,9 @@ void ReadSensors(bool firstTime, bool readOnly)
   uint8_t pressure_current;
   int32_t weight1_current;
   int32_t weight2_current;
-  int16_t temp_last;
   int16_t temp_change;
   int32_t weight_current32;
   uint16_t weight_current;
-  uint16_t weight_last;
 
   if (fBme) {
     /* warm up the BME280 by discarding a measurement */
@@ -660,17 +669,6 @@ void ReadSensors(bool firstTime, bool readOnly)
   weight_current = (uint16_t)weight_current32;
 
   if (not(readOnly)) {
-    // calculate last value
-    weight_last = 0;
-    temp_last = lora_data.temperature;
-
-    for (int i = 0; i < my_position; i++) {
-      temp_last = temp_last + lora_data.temperature_change[i];
-    }
-
-    if (my_position > 0) {
-      weight_last = lora_data.weight[my_position - 1];
-    }
 
     if (firstTime) {
       lora_data_first.vbat = GetVBatValue((int)(vBat * 1000.0f));
@@ -686,7 +684,7 @@ void ReadSensors(bool firstTime, bool readOnly)
       if (my_position == 0) {
         lora_data.temperature = temp_current;
       } else {
-        temp_change = temp_current - temp_last;
+        temp_change = temp_current - last_sensor_reading.temperature;
         if (temp_change > 127) {
           temp_change = 127;
         }
@@ -709,9 +707,9 @@ void ReadSensors(bool firstTime, bool readOnly)
 
     // Should we send the Data?
     // we send data the first time the system is started, when the array is full
-    // or when the weight has fallen more than 100g or the first measurement is
+    // or when the weight has fallen more than threshold or the first measurement is
     // more than one hour old (which should not happen :-) )
-    if (firstTime || (my_position >= MAX_VALUES_TO_SEND) || ((weight_last - weight_current) > 20) || ((millis() - timer_pos0) > 3600000)) {
+    if (firstTime || (my_position >= MAX_VALUES_TO_SEND) || ((last_sensor_reading.weight - weight_current) > SEND_DIFF_THRESHOLD_5GRAMS) || ((millis() - timer_pos0) > 3600000)) {
       lora_data.offset_last_reading = (uint8_t)((millis() - timer_pos0) / 1000 / 60);
       gCatena.SafePrintf("startSendingUplink()\n");
       startSendingUplink(firstTime);