From 43d4b7d82d483ee647bb660672b582cdaf6d8f26 Mon Sep 17 00:00:00 2001
From: bzi <mail@bzi.one>
Date: Fri, 1 Mar 2019 09:15:17 +0100
Subject: [PATCH] Merge absolute humidity and plausibility checks into espsens

---
 espsens/espsens.ino | 67 +++++++++++++++++++++++++--------------------
 1 file changed, 38 insertions(+), 29 deletions(-)

diff --git a/espsens/espsens.ino b/espsens/espsens.ino
index 9c26b8d..9fd6649 100644
--- a/espsens/espsens.ino
+++ b/espsens/espsens.ino
@@ -18,10 +18,21 @@
 #define TOPIC_TEMP TOPIC_BASE "temperature"
 #define TOPIC_HMID TOPIC_BASE "humidity"
 #define TOPIC_HEAT TOPIC_BASE "heat_index"
+#define TOPIC_ABHU TOPIC_BASE "abs_humidity"
 
 #define DIFF_TEMP 0.3 // sensor has only 0.5°C accuracy, triggering on less is ludicrous
 #define DIFF_HMID 2.5 // humidity doesn't change that much anyways
 #define DIFF_HEAT 0.2 // this one's actually quite active
+#define DIFF_ABHU 0.1 // small changes mean quite something
+
+float hmid = 0; // humidity
+float hmid_r = 0; // humidity
+float abhu = 0; // absolute humidity
+float abhu_r = 0; // absolute humidity
+float temp = 0; // temperature
+float temp_r = 0; // temperature
+float heat = 0; // heat index
+float heat_r = 0; // heat index
 
 #define DHTPIN 4     // Digital pin connected to the DHT sensor
 #define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
@@ -85,29 +96,36 @@ void reconnect() {
   }
 }
 
-bool checkBound(float newValue, float prevValue, float maxDiff) {
+bool checkVariation(float newValue, float prevValue, float maxDiff) {
   return !isnan(newValue) &&
          (newValue < prevValue - maxDiff || newValue > prevValue + maxDiff);
 }
 
+bool checkPlausibility(float newValue, float prevValue, float maxDiff) {
+  return (newValue < prevValue + (maxDiff * 10) || newValue > prevValue - (maxDiff * 10));
+}
+
 long lastMsg = 0;
-float t_r = 0.0;
-float h_r = 0.0;
-float hi_r = 0.0;
 long lastSent = 0; 
 bool published = false;
 bool forcePublish = false;
 
-bool publish (String desc, char *topic, float val, float &val_r, int diff, bool force){
-    if (checkBound(val, val_r, 0.3) or force) {
-      val_r = val;
-      Serial.print("New " + desc + ": ");
-      Serial.println(String(val).c_str());
+bool publish (String desc, char *topic, float val, float &lastVal, float diff, bool force){
+  bool retval = false;
+  Serial.println("Sample " + desc + ": " + String(val).c_str());
+  if (checkVariation(val, lastVal, diff) or force) {
+    lastVal = val;
+    Serial.println("Sufficient variation on " + desc + ": " + String(val).c_str());
+    if (checkPlausibility(val, lastVal, diff) or force) {
+      Serial.println("Value published");
       client.publish(topic, String(val).c_str(), true);
-      return true;
+      retval = true;
     } else {
-      return false;
+      Serial.print("** ERROR: Value out of bounds, not published. Last value :");
+      Serial.println(String(lastVal).c_str());
     }
+  }
+  return retval;
 }
 
 void loop() {
@@ -125,24 +143,14 @@ void loop() {
     lastMsg = now;
     if (OPERATION_BLINK_EN) {digitalWrite(LED_BUILTIN, HIGH);}
 
-    float h = dht.readHumidity();
-    float t = dht.readTemperature();
+    hmid = dht.readHumidity();
+    temp = dht.readTemperature();
   
-    if (isnan(h) || isnan(t)) {
-      Serial.println(F("Failed to read from DHT sensor!"));
-      return;
+    if (!isnan(hmid) && !isnan(temp)){
+      abhu = (6.112 * ( pow(2.71828, ((17.67 * temp) / (temp + 243.5))) * hmid * 2.1674)) / (273.15 + temp);
+      heat = dht.computeHeatIndex(temp, hmid, false);
     }
  
-    float hi = dht.computeHeatIndex(t, h, false);
-
-    Serial.print(F("Humidity: "));
-    Serial.print(h);
-    Serial.print(F("%  Temperature: "));
-    Serial.print(t);
-    Serial.print(F("°C  Heat index: "));
-    Serial.print(hi);
-    Serial.println(F("°C "));
-
     published = false;
     if (lastSent > FORCE_PERIOD) {
       Serial.println(F("Forcing a publish of all values"));
@@ -150,9 +158,10 @@ void loop() {
       lastSent = 0;
     }
 
-    published += publish("temperature", TOPIC_TEMP, t, t_r, DIFF_TEMP, forcePublish);
-    published += publish("humidity", TOPIC_HMID, h, h_r, DIFF_HMID, forcePublish);
-    published += publish("heat index", TOPIC_HEAT, hi, hi_r, DIFF_HEAT, forcePublish);
+    published += publish("temperature", TOPIC_TEMP, temp, temp_r, DIFF_TEMP, forcePublish);
+    published += publish("humidity", TOPIC_HMID, hmid, hmid_r, DIFF_HMID, forcePublish);
+    published += publish("heat index", TOPIC_HEAT, heat, heat_r, DIFF_HEAT, forcePublish);
+    published += publish("absolute humidity", TOPIC_ABHU, abhu, abhu_r, DIFF_ABHU, forcePublish);    
     
     if (published == false) {
       lastSent = lastSent + 1;