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Top Forums Programming NodeMCU ESP8266 Blynk SSL Application for Linux Server Load Averages Post 303043556 by Neo on Friday 31st of January 2020 11:56:26 AM
Old 01-31-2020
Update; Version 0.2

Changes: Added 30 minute session activity for members, guests and bots. Reorganized gauges. Changed name to "Load Averages & Users"

NodeMCU ESP8266 Blynk SSL Application for Linux Server Load Averages-img_2153333406a8-1jpeg

  This Arduino sketch is for the NodeMCU ESP8266  v0.2
  The code makes a GET request to a remote Linux server PHP API using SSL
  and GETs the Linux load averages and basic user stats as a simple string, parses the
  string in a very basic way display the results on a Blynk apply
  using virtual pins v0, v1, v2, v3, v4, and v5.

  The entire sketch should be rewritten to use JSON.

  Use anyway you wish, freely and at your own risk of course.

  Neo  January 31, 2020
  v0.11  removed  delay(2000); //GET Data at every 2 seconds per PeteKnight

  Download latest Blynk library here:

  Blynk is a platform with iOS and Android apps to control
  Arduino, Raspberry Pi and the likes over the Internet.
  You can easily build graphic interfaces for all your
  projects by simply dragging and dropping widgets.

    Downloads, docs, tutorials:
    Sketch generator: 
    Blynk community:  
    Follow us:        

  Blynk library is licensed under MIT license
  This example code is in public domain.

  This example runs directly on NodeMCU.

  Note: This requires ESP8266 support package:

  Please be sure to select the right NodeMCU module
  in the Tools -> Board menu!

  Change WiFi ssid, pass, and Blynk auth token to run :)
  Feel free to apply it to any other example. It's simple!

/* Comment this out to disable prints and save space */
#define BLYNK_PRINT Serial
#define DEBUG false
#include <SPI.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <WiFiClientSecure.h>
#include <ESP8266HTTPClient.h>
//#include <ArduinoJson.h> . // unused for now
BlynkTimer timer;
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "YOUR_BLYNK_AUTH_KEY";

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "YOUR_WIFI_SSID";
char pass[] = "YOUR_SECURE_PASSWORD";

const char *host = "";
const int httpsPort = 443;  //HTTPS= 443 and HTTP = 80

//SHA1 fingerprint of certificate. Use your web browser to view the SHA1 fingerprint and copy
//Reply in this discussion if you don't know how to get the SHA1 fingerprint of your HTTPS website, thanks.
const char fingerprint[] PROGMEM = "AA BB DD 7B C0 FE CF 3C A8 2B 6D 31 DB 4B 9F C3 5B 6E A0 DD"; 

void setup()
  // Debug serial console

  Blynk.begin(auth, ssid, pass);
  timer.setInterval(1000L, myTimerEvent);


void loop()

void myTimerEvent()
  WiFiClientSecure httpsClient;    //Declare object of class WiFiClient


  Serial.printf("Using fingerprint '%s'\n", fingerprint);
  httpsClient.setTimeout(15000); // 15 Seconds

  Serial.print("HTTPS Connecting");
  int r = 0; //retry counter
  while ((!httpsClient.connect(host, httpsPort)) && (r < 30)) {
  if (r == 30) {
    Serial.println("Connection failed");
  else {
    Serial.println("Connected to web");

  String Link;
  long rssi = WiFi.RSSI();
  String macaddr = WiFi.macAddress();
  Serial.print("MAC: ");

  Link = "/yourAPIdirectory/?type=t&rssi=" + String(rssi) + "&mac=" + macaddr;
  Serial.print("requesting URL: ");
  Serial.println(host + Link);

  httpsClient.print(String("GET ") + Link + " HTTP/1.1\r\n" +
                    "Host: " + host + "\r\n" +
                    "Connection: close\r\n\r\n");

  Serial.println("request sent");

  while (httpsClient.connected()) {
    String line = httpsClient.readStringUntil('\n');
    if (line == "\r") {
      Serial.println("headers received");

  Serial.println("reply was:");
  String line;
  while (httpsClient.available()) {
    line = httpsClient.readStringUntil('\n');  //Read Line by Line
    Serial.println(line); //Print response
  Serial.println("closing connection");

  // crude way to parse string - should convert to json later
  int ind1 = line.indexOf(':');  //finds location of first :
  String l1 = line.substring(0, ind1);   //captures first data String
  int ind2 = line.indexOf(':', ind1 + 1 ); //finds location of second :
  String l5 = line.substring(ind1 + 1, ind2 + 1); //captures second data String
  int ind3 = line.indexOf(':', ind2 + 1 ); //finds location of third :
  String l15 = line.substring(ind2 + 1, ind3 + 1);//captures second data String
  int ind4 = line.indexOf(':', ind3 + 1 ); //finds location of third :
  String bots = line.substring(ind3 + 1, ind4 + 1);//captures second data String
  int ind5 = line.indexOf(':', ind4 + 1 ); //finds location of third :
  String guests = line.substring(ind4 + 1, ind5 + 1);//captures second data String
  int ind6 = line.indexOf(':', ind5 + 1 ); //finds location of third :
  String members = line.substring(ind5 + 1, ind6 + 1);//captures second data String
  if (DEBUG) {
    Serial.println(String(l1)); Serial.println(l5);; Serial.println(l15); //Print response
    Serial.println(String(bots)); Serial.println(guests);; Serial.println(members);

  if (l1.toFloat() > 0) {
    l1.replace(":", ""); l5.replace(":", ""); l15.replace(":", "");
    bots.replace(":", ""); guests.replace(":", ""); members.replace(":", "");
    Blynk.virtualWrite(V0, l1.toFloat());
    Blynk.virtualWrite(V1, l5.toFloat());
    Blynk.virtualWrite(V2, l15.toFloat());
    Blynk.virtualWrite(V3, members.toInt());
    Blynk.virtualWrite(V4, guests.toInt());
    Blynk.virtualWrite(V5, bots.toInt());


This more-than-like will be the last Blynk app I create because, with only six gauges, I have reached the limit of the "freebies" and if I create more apps and add more widgets, I will start to have to pay for them.

I may add some "color logic" when the numbers exceed certain thresholds, otherwise I'm most "done and dusted" with this test app.

Anyway, time to move on to another Arduino module.

This app was fun, fast useful and easy to build. Recommended for sure.
Test Your Knowledge in Computers #644
Difficulty: Easy
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