Using JSON data to turn on an LED

Projects Programming
1

Hi all, I've successfully grabbed some json data from a project i am working on and being able to print the data and display it on an OLED screen but i am having trouble using the data to do other things.

I want to be able to light an LED if the colour sent back in the const char* field is yellow or green etc. I have no idea how to do this as of yet, any help would be appreciated.

see attachment or code below.

thanks

const size_t capacity = JSON_OBJECT_SIZE(7) + 100;
DynamicJsonDocument doc(capacity);
String payload = http.getString();
const char* json = payload.c_str();

deserializeJson(doc, json);

const char* colour = doc["colour"]; // "yellow"
const char* side = doc["side"]; // "buy"
const char* sizeBtc = doc["sizeBtc"]; // "0.05"
const char* price = doc["price"]; // "8267.0"
long time = doc["time"]; // 1595590955
const char* readableTime = doc["readableTime"]; // "24/07/2020 11:42:35"
float gecko = doc["gecko"]; // 8191.32

Screenshot 2020-07-25 at 23.33.07.png
Screenshot 2020-07-25 at 23.33.07.png1102×506 83.7 KB

2

Your sketch doesn’t compile. Please provide a complete sketch that compiles and posted in [​code]code tags[​/code]. You can insert them with the </> button on the posting toolbar, or use the “copy code for forum” option on the edit menu in the Arduino IDE.

3 
//Includes-------------------------------------------|

#include "WiFi.h"

#include <ArduinoJson.h>

#include <HTTPClient.h>

#include "U8g2lib.h"

//Definitions-----------------------------------------|

#define   FONT_ONE_HEIGHT               8                  // font one height in pixels
#define   FONT_TWO_HEIGHT               20                 // font two height in pixels

#define ONBOARD_LED  25



//Constants and Variables----------------------------|

char            chPassword[] = "oldman 1952";
char            chSSID[] = "Winterfell";


char            chBuffer[128];

//String ("colour") = yellow;


U8G2_SSD1306_128X64_NONAME_F_HW_I2C     u8g2(U8G2_R0, 16, 15, 4);


//Setup----------------------------------------------|

void setup() {

  Serial.begin (115200);

  pinMode(ONBOARD_LED, OUTPUT);

  Serial.print("Connecting to Wifi");
  WiFi.begin (chSSID, chPassword);
  while (WiFi.status() != WL_CONNECTED)
  {
    Serial.print(".");
    delay (1250);
  }
  // Oled Screen Startup

  u8g2.begin();
  u8g2.setFont(u8g2_font_6x10_tr);
  u8g2.setFontRefHeightExtendedText();
  u8g2.setDrawColor(1);
  u8g2.setFontPosTop();
  u8g2.setFontDirection(0);

  // Display Wifi Connecting to....

  u8g2.clearBuffer();
  sprintf(chBuffer, "%s", "Connecting to:");
  u8g2.drawStr(64 - (u8g2.getStrWidth(chBuffer) / 2), 0, chBuffer);
  sprintf(chBuffer, "%s", chSSID);
  u8g2.drawStr(64 - (u8g2.getStrWidth(chBuffer) / 2), 31 - (FONT_ONE_HEIGHT / 2), chBuffer);
  u8g2.sendBuffer();

  delay(1000);
  
  u8g2.clearBuffer();

  sprintf(chBuffer, "%s", "WiFi Stats:");
  u8g2.drawStr(64 - (u8g2.getStrWidth(chBuffer) / 2), 0, chBuffer);

  // Display the ssid of the wifi router.

  sprintf(chBuffer, "SSID: %s", chSSID);
  u8g2.drawStr(0, FONT_ONE_HEIGHT * 3, chBuffer);

  // Display the rssi.

  sprintf(chBuffer, "RSSI: %d", WiFi.RSSI());
  u8g2.drawStr(0, FONT_ONE_HEIGHT, chBuffer);


  u8g2.sendBuffer();

  delay(3000);


}
//Loop-----------------------------------------------|

void loop() {
  if ((WiFi.status() == WL_CONNECTED))
    Serial.println ("Connected: ");
  Serial.print (WiFi.localIP());
  {

    HTTPClient http;

    http.begin ("http://www.dogstarweb.co.uk/coinfalcon/botty/led.php");
    int httpCode = http.GET();

    if (httpCode > 0) {

    }
    sprintf(chBuffer, "WiFi connected to %s.", chSSID);
    u8g2.clearBuffer();

    Serial.println ("\nHTTP statuscode: " + String(httpCode));
    delay (1000);



    const size_t capacity = JSON_OBJECT_SIZE(7) + 100;
    DynamicJsonDocument doc(capacity);
    String payload = http.getString();
    const char* json = payload.c_str();

    deserializeJson(doc, json);

    const char* colour = doc["colour"]; // "yellow"
    const char* side = doc["side"]; // "buy"
    const char* sizeBtc = doc["sizeBtc"]; // "0.05"
    const char* price = doc["price"]; // "8267.0"
    long time = doc["time"]; // 1595590955
    const char* readableTime = doc["readableTime"]; // "24/07/2020 11:42:35"
    float gecko = doc["gecko"]; // 8191.32

    //Serial Outputs----------------------------|


    Serial.println("-------------------------------");
    Serial.print("Side: ");
    Serial.println(side);
    Serial.print("colour: ");
    Serial.println(colour);
    Serial.print("Size: ");
    Serial.println(sizeBtc);
    Serial.print("Price: ");
    Serial.println(price);
    Serial.print("Time: ");
    Serial.println(readableTime);
    Serial.print("BTC Price: ");
    Serial.println(gecko);
    Serial.println("-------------------------------");


    //Screen Outputs----------------------------|

    
    u8g2.clearBuffer();

    u8g2.setCursor(0, 0);
    u8g2.print("Side: ");
    u8g2.print(side);
    u8g2.setCursor(0, 10);
    u8g2.print("Size: ");
    u8g2.print(sizeBtc);
    u8g2.setCursor(0, 20);
    u8g2.print("Colour: ");
    u8g2.print(colour);
    u8g2.setCursor(0, 30);
    u8g2.print("Price: ");
    u8g2.print(price);
    u8g2.setCursor(0, 40);
    u8g2.print("Time: ");
    u8g2.print(readableTime);
    u8g2.setCursor(0, 50);
    u8g2.print("Gecko Price: ");
    u8g2.print(gecko, 2);

    u8g2.sendBuffer();


    http.end();

  
  }
  delay (60000);
}