Notifications in constant loop (Blynk) trying to trigger along with serial function

Question

This is an extension from a previous thread that was getting lengthy and off the original topic. I have the following code which monitors the state of a float switch (high or low). I upload the sketch, turn on the serial monitor and manually move the float switch up and down. The serial monitor output represents what I'm doing with the switch. The issue is that I get a constant loop of blynk notifications, every 15 seconds or so. Furthermore, if i move the switch to it's low position, the first blynk notification i get is correct reading "low", the following notifications are "high" thereafter. When the switch is moved to the high position, blynk just loops stating it's "high". I know it's weird and took quite a while to even establish what is going on here. but the biggest issue is the loop of notifications every 15 seconds.

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
BlynkTimer timer;

char auth[] = "710a4af9b1d82412fa477705bf642c634";
char ssid[] = "ssid";
char pass[] = "pwd";
int flag=0;
int floatSavedState = -1;      // initial float low state indicates not yet known

void notifyOnButtonPress()
{
  // pin D1 will be 1 if float has dropped due to low water level
  // pin D1 will be 0 if water level is high enough
  int floatLevelLow = digitalRead(D1);  // read the float low indicator pin

  if (floatLevelLow && floatLevelLow != floatSavedState) {
       // send notification if this is first time or if the float level has
       // changed since the last notification.
       Serial.println("Resevoir Water is Low!");
       Blynk.notify("Alert : Water Level low.");
       floatSavedState = floatLevelLow;
  } else if (floatLevelLow != floatSavedState)  
     // send notification if this is first time or if the float level has
     // changed since the last notification.
     Serial.println("Resevoir Water is High!");
     Blynk.notify("Alert : Water level high");
     floatSavedState = floatLevelLow;

}
void setup()
{
  // Debug console
  Serial.begin(9600);
Blynk.begin(auth, ssid, pass);
  // Setup notification button on pin D1
  pinMode(D1,INPUT_PULLUP);
 timer.setInterval(16000L,notifyOnButtonPress);

}
void loop()
{
  Blynk.run();
  timer.run(); // Initiates BlynkTimer
}

Answer 1

Your code:

timer.setInterval(16000L,notifyOnButtonPress);

Is calling this function every 16s.

This code:

if (floatLevelLow && floatLevelLow != floatSavedState) {

needs some parentheses to force your desired order-of-operations. As it stands now, you are asking the result of floatLevelLow && floatLevelLow and comparing if that is not equal to floatSavedState. That's likely not what you want.

Did you mean:

if (floatLevelLow && (floatLevelLow != floatSavedState)) {

EDIT:

Also, your if/else is missing brackets around the 2nd clause and should be:

} else if (floatLevelLow != floatSavedState) {
     // send notification if this is first time or if the float level has
     // changed since the last notification.
     Serial.println("Resevoir Water is High!");
     Blynk.notify("Alert : Water level high");
     floatSavedState = floatLevelLow;
}