Bitcoin Price Monitoring

1//=============================================================================
2// Track Bitcoin prices automatically with an ESP32 and an OLED display
3// Created on 19 August 2024
4// Created by Lucas Fernando (https://www.youtube.com/@lucasfernandochannel)
5// You are free to use this code the way you want
6//=============================================================================
7
8#include <WiFi.h>
9#include <HTTPClient.h>
10#include <ArduinoJson.h>
11#include <Adafruit_GFX.h>
12#include <Adafruit_ST7789.h>
13#include <SPI.h>
14
15// Replace with your network credentials
16const char* ssid = "";
17const char* password = "";
18
19// Replace with your CoinAPI key
20const char* api_key = "";
21const char* api_url = "https://rest.coinapi.io/v1/exchangerate/BTC/USD";
22
23// Define the waiting time between the API calls
24const int waiting_time = 900000; // Wait for 15 minutes
25
26// Define the pins
27#define TFT_CS 5
28#define TFT_RST 4
29#define TFT_DC 2
30
31// Initialize the ST7789 display
32Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);
33
34void setup() {
35  // Initialize serial communication
36  Serial.begin(115200);
37
38  // Initialize the display
39  tft.init(135, 240);
40  tft.setRotation(3);
41  tft.fillScreen(ST77XX_BLACK);
42
43  // Connect to Wi-Fi
44  connectToWiFi();
45
46  // Make API call and display the result
47  displayBitcoinPrice();
48}
49
50void loop() {
51  delay(waiting_time);
52  displayBitcoinPrice();  
53}
54
55void connectToWiFi() {
56  tft.setCursor(10, 10);
57  tft.setTextColor(ST77XX_WHITE);
58  tft.setTextSize(2);
59  tft.print("Connecting to Wi-Fi");  
60
61  WiFi.begin(ssid, password);
62
63  while (WiFi.status() != WL_CONNECTED) {
64    delay(1000);
65    Serial.println("Connecting...");  
66  }
67
68  Serial.println("Connected to Wi-Fi");
69  tft.fillScreen(ST77XX_BLACK);
70}
71
72String formatTime(String time) {
73  // Extract date and time components
74  String date = time.substring(0, 10);
75  String timeOfDay = time.substring(11, 16);
76
77  // Convert date components
78  String year = date.substring(0, 4);  // Year
79  String month = date.substring(5, 7);  // Month
80  String day = date.substring(8, 10);  // Day
81
82  // Convert the month number to the month name
83  String monthNames[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", 
84                         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
85  int monthIndex = month.toInt() - 1;
86  String monthName = monthNames[monthIndex];
87
88  // Convert time from 24-hour to 12-hour format
89  int hour = timeOfDay.substring(0, 2).toInt();
90  String minute = timeOfDay.substring(3, 5);  // Minute
91  String period = "AM";
92
93  if (hour >= 12) {
94    period = "PM";
95    if (hour > 12) hour -= 12;
96  } else if (hour == 0) {
97    hour = 12; // Midnight case
98  }
99
100  String formattedTime = monthName + " " + day + ", " + year + ", ";
101  formattedTime += String(hour) + ":" + minute + " " + period + " UTC";
102
103  return formattedTime;
104}
105
106
107void displayBitcoinPrice() {
108  if (WiFi.status() == WL_CONNECTED) {
109    HTTPClient http;
110    http.begin(api_url);
111    http.addHeader("X-CoinAPI-Key", api_key);
112
113    int httpCode = http.GET(); // Make the request
114
115    if (httpCode > 0) {
116      String payload = http.getString();
117      Serial.println(payload);
118      
119      DynamicJsonDocument doc(1024);
120      deserializeJson(doc, payload);
121
122      float price = doc["rate"];
123      String date = doc["time"];
124
125      // Display the price on the OLED
126      tft.fillScreen(ST77XX_BLACK);
127      tft.setTextColor(ST77XX_WHITE);
128      tft.setCursor(0, 0);
129      tft.setTextSize(3);
130      tft.print("Bitcoin Price");
131      tft.setCursor(0, 30);
132      tft.print("USD ");
133      tft.setCursor(70, 30);
134      tft.print(price, 2);
135
136      String formatted_date = formatTime(date);
137
138      tft.setTextSize(1);
139      tft.setCursor(0, 115);
140      tft.print(formatted_date);
141      tft.setCursor(0, 125);
142      tft.print("Update every 15 minutes");
143    } else {
144      Serial.println("Error on HTTP request");  
145    }
146    http.end(); // End the request
147  }  
148}