Simple program: How to send duration and time of pushed button?

Question

I have ESP8266 ESP-12E with microswitch connected to GPIO13 (and ground).

I want to send (preferably using HTTP POST but I'm open to something else if it's bad choice) duration of time holding down the button and time counting from ESP8266 start to the time when the button is pushed.

Here is what I coded so far:

#include <ESP8266WiFi.h>

long duration = 0;
long startTime = 0;

const char* ssid     = "SSID";
const char* password = "password";

void sendClick(int startTime, int duration) {
  char* server = "192.168.0.15";
  Serial.println(server);
  WiFiClient client;
  if (client.connect(server,80)) {
    String postStr = "id=1&time=";
    postStr += String(startTime);
    postStr +="&duration=";
    postStr += String(duration);
    postStr += "\n";
    client.print("POST /click HTTP/1.1\n");
    client.print("Host: ");
    client.print(server);
    client.print("\n");
    client.print("Connection: close\n");
    client.print("Content-Type: application/x-www-form-urlencoded\n");
    client.print("Content-Length: ");
    client.print(postStr.length());
    client.print("\n\n");
    client.print(postStr);
    client.stop();
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(13, INPUT_PULLUP);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  if (digitalRead(13) == LOW) {
    delay(25); //for eliminating microswitch's bounce
    if (digitalRead(13) == LOW) {
      duration = 25;
      startTime = millis();
      while (digitalRead(13) == LOW) {}
      duration += millis()-startTime;
      Serial.print("Duration: ");
      Serial.print(duration);
      Serial.print(" startTime: ");
      Serial.print(startTime);
      Serial.print("\r\n");
      sendClick(startTime, duration);
    }
  }
}

However, my code is wrong because I need to wait for the request to be completed before pushing down the button again.

I'm thinking about putting duration and startTime in some arrays using interrupts, eg.:

attachInterrupt(13, buttonClick, CHANGE);

and then I could continuously check if the arrays contains new clicks and send them to the server.

But I'm not sure if that would work and I have too little experience in Arduino/C in general. Any help would be appreciated.

score 0 · Answer 1 · answered Sep 09 '16 at 12:36

I would not block (while (digitalRead(13) == LOW) {}) within your loop. That is holding up execution for an indeterminate amount of time. Loop is not like a main function, it is called repeatedly and other things can happen while outside the loop (like interrupts), so blocking it for long periods of time could be bad.

Rather than that I would test for state changes within the loop. Something like this (untested):

if (button_is_currently_down() && !button_was_down)
{
  // button has transitioned to "down" state
  button_was_down = TRUE;
  startTime = millis();
} 
else
{
  if (button_was_down) {
    // button has transitioned to "up" state
    sendClick(startTime, millis() - startTime);
    startTime = 0;
    button_was_down = FALSE;
  }
}

Simple program: How to send duration and time of pushed button?

1 Answers1