From eda866b36dbaf3dcb69a7f61ecf2ed000fbee127 Mon Sep 17 00:00:00 2001
From: structix <amateurdoedel@gmail.com>
Date: Sun, 27 Aug 2017 17:28:48 +0200
Subject: [PATCH] Overflow error prevention and minor improvements for the
 esp8266

---
 ESP8266/sensornode/sensornode.ino | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/ESP8266/sensornode/sensornode.ino b/ESP8266/sensornode/sensornode.ino
index 1eccfee..67269e7 100644
--- a/ESP8266/sensornode/sensornode.ino
+++ b/ESP8266/sensornode/sensornode.ino
@@ -1,10 +1,13 @@
 #include "DHT.h"
 #include <ESP8266WiFi.h>
 #include "aREST.h"
+#include <climits>
 
 //DHT settings:
 #define DHTPIN 14     // what digital pin we're connected to
 
+#define MEASURESECONDS 60 //shouldn't be < 2sec
+
 // Uncomment whatever type you're using!
 //#define DHTTYPE DHT11   // DHT 11
 #define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
@@ -27,8 +30,8 @@ DHT dht(DHTPIN, DHTTYPE);
 aREST rest = aREST();
 
 // WiFi settings:
-const char* ssid = "Signal im Regal";
-const char* password = "42003489";
+const char* ssid = "Your_SSID";
+const char* password = "Your_Password";
 
 #define LISTEN_PORT 80
 
@@ -42,8 +45,10 @@ float humidity;
 
 
 //milli counter
-long millitotal = 0;
+unsigned long millitotal = 0;
 
+//First measurement
+bool firstmeasurement = true;
 
 
 void setup() {
@@ -57,7 +62,7 @@ void setup() {
   rest.variable("temperature", &temperature);
   rest.variable("humidity", &humidity);
 
-  // Give name & ID to the device (ID should be 6 characters long)
+  // Set a ID (ID must be greater than 0)
   rest.set_id("1");
   rest.set_name("sensornode");
 
@@ -82,6 +87,7 @@ void setup() {
 void loop() {
   // Wait a few seconds between measurements.
   float millicounter = millis();
+  
   if (millicounter >= millitotal) {
     // Reading temperature or humidity takes about 250 milliseconds!
     // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
@@ -97,11 +103,15 @@ void loop() {
       //set the new values
       humidity = h;
       temperature = t;
-    
     }
 
     //set new milli counter
-    millitotal = millis() + 2000;
+    //millis will overflow after approx. 52 days. To prevent errors we're checking the limits
+    if (millis() + MEASURESECONDS * 1000 <= ULONG_MAX) {
+      millitotal = millis() + 2000;
+    } else {
+      millitotal = 0;
+    }
   }
   // Handle REST calls
   WiFiClient client = server.available();
@@ -112,4 +122,7 @@ void loop() {
     delay(1);
   }
   rest.handle(client);
+
+  //Let the esp chill a bit
+  delay(100);
 }