前言
2018年開始投資比特幣等數(shù)字貨幣，不料一路暴跌，血虧之后，卸載所有 app 。
計劃屯幣到2020年，等比特幣再次減半，希望到時能回本或者小賺。
總得做點什么紀念這次失敗的炒幣行動，作為一個程序員，只能用代碼來表示了。
決定做一個簡單的比特幣示價器，隨時隨地可以查看價格。
前期準備
硬件部分
- ESP8266 NodeMcu WIFI??
? ? 這是一款類似 Arduino 一樣操作硬件IO的設備，支持Nodejs 類似語法，而且集成了一個超低成本的 wifi 模塊。非常適合我們用來做一些小玩意。
- 0.96寸OLED顯示屏
?????一個非常小的單色顯示器，不支持中文顯示，優(yōu)點僅僅是便宜！
- 母對母杜邦線
? ? 為了連接芯片和顯示器用的。
軟件部分
由于我用的是 macbook 所以，下載地址都是 mac 版本的。其他平臺請到官網(wǎng)下載相應版本
- Arduino
? ?下載地址：https://www.arduino.cc/en/Main/Software
- CH340/CH341的USB轉(zhuǎn)串口驅(qū)動程序
? 下載地址：http://www.wch.cn/download/CH341SER_MAC_ZIP.html
連接方式：
代碼
/*******************************************************************
? ? A project to display crypto currency prices using an ESP8266
? ? Main Hardware:
? ? - NodeMCU Development Board (Any ESP8266 dev board will work)
? ? - OLED I2C Display (SH1106)
? ? Written by Brian Lough
? ? https://www.youtube.com/channel/UCezJOfu7OtqGzd5xrP3q6WA
*******************************************************************/
// ----------------------------
// Standard Libraries - Already Installed if you have ESP8266 set up
// ----------------------------
#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <Wire.h>
// ----------------------------
// Additional Libraries - each one of these will need to be installed.
// ----------------------------
#include <CoinMarketCapApi.h>
// For Integrating with the CoinMarketCap.com API
// Available on the library manager (Search for "CoinMarket")
// https://github.com/witnessmenow/arduino-coinmarketcap-api
#include "SH1106.h"
// The driver for the OLED display
// Available on the library manager (Search for "oled ssd1306")
// https://github.com/squix78/esp8266-oled-ssd1306
#include <ArduinoJson.h>
// !! NOTE !!: When installing this select an older version than V6 from the drop down
// Required by the CoinMarketCapApi Library for parsing the response
// Available on the library manager (Search for "arduino json")
// https://github.com/squix78/esp8266-oled-ssd1306
// ----------------------------
// Configurations - Update these
// ----------------------------
char ssid[] = " wifi 名";? ? ? // your network SSID (name)
char password[] = " wifi 密碼";? // your network key
// Pins based on your wiring
#define SCL_PIN D5
#define SDA_PIN D3
// CoinMarketCap's limit is "no more than 10 per minute"
// Make sure to factor in if you are requesting more than one coin.
// We'll request a new value just before we change the screen so it's the most up to date
unsigned long screenChangeDelay = 3500; // Every 10 seconds
// Have tested up to 10, can probably do more
#define MAX_HOLDINGS 10
#define CURRENCY "usd" //See CoinMarketCap.com for currency options (usd, gbp etc)
#define CURRENCY_SYMBOL "$" // Euro doesn't seem to work, $ and ￡ do
// You also need to add your crypto currecnies in the setup function
// ----------------------------
// End of area you need to change
// ----------------------------
WiFiClientSecure client;
CoinMarketCapApi api(client);
SH1106 display(0x3c, SDA_PIN, SCL_PIN);
unsigned long screenChangeDue;
struct Holding {
? String tickerId;
? float amount;
? bool inUse;
? CMCTickerResponse lastResponse;
};
Holding holdings[MAX_HOLDINGS];
int currentIndex = -1;
String ipAddressString;
void addNewHolding(String tickerId, float amount = 0) {
? int index = getNextFreeHoldingIndex();
? if (index > -1) {
? ? holdings[index].tickerId = tickerId;
? ? holdings[index].amount = amount;
? ? holdings[index].inUse = true;
? }
}
void setup() {
? Serial.begin(115200);
? // ----------------------------
? // Holdings - Add your currencies here
? // ----------------------------
? // Go to the currencies coinmarketcap.com page
? // and take the tickerId from the URL (use bitcoin or ethereum as an example)
? addNewHolding("bitcoin");
? addNewHolding("eos");
? addNewHolding("ethereum");
? addNewHolding("huobi-token");
? // ----------------------------
? // Everything below can be thinkered with if you want but should work as is!
? // ----------------------------
? // Initialising the display
? display.init();
? display.setTextAlignment(TEXT_ALIGN_CENTER);
? display.setFont(ArialMT_Plain_16);
? display.drawString(64, 0, F("BTC ETH EOS"));
? display.setFont(ArialMT_Plain_24);
? display.drawString(64, 18, F("DaZhang!!"));
? display.setFont(ArialMT_Plain_10);
? display.drawString(64, 42, F("desigen By zjm"));
? display.display();
? // Set WiFi to station mode and disconnect from an AP if it was Previously
? // connected
? WiFi.mode(WIFI_STA);
? WiFi.disconnect();
? delay(100);
? // Attempt to connect to Wifi network:
? Serial.print("Connecting Wifi: ");
? Serial.println(ssid);
? WiFi.begin(ssid, password);
? while (WiFi.status() != WL_CONNECTED) {
? ? Serial.print(".");
? ? delay(500);
? }
? Serial.println("");
? Serial.println("WiFi connected");
? Serial.println("IP address: ");
? IPAddress ip = WiFi.localIP();
? Serial.println(ip);
? ipAddressString = ip.toString();
}
int getNextFreeHoldingIndex() {
? for (int i = 0; i < MAX_HOLDINGS; i++) {
? ? if (!holdings[i].inUse) {
? ? ? return i;
? ? }
? }
? return -1;
}
int getNextIndex() {
? for (int i = currentIndex + 1; i < MAX_HOLDINGS; i++) {
? ? if (holdings[i].inUse) {
? ? ? return i;
? ? }
? }
? for (int j = 0; j <= currentIndex; j++) {
? ? if (holdings[j].inUse) {
? ? ? return j;
? ? }
? }
? return -1;
}
void displayHolding(int index) {
? CMCTickerResponse response = holdings[index].lastResponse;
? display.clear();
? display.setTextAlignment(TEXT_ALIGN_CENTER);
? display.setFont(ArialMT_Plain_16);
? display.drawString(64, 0, response.symbol);
? display.setFont(ArialMT_Plain_24);
? double price = response.price_currency;
? if (price == 0) {
? ? price = response.price_usd;
? }
? display.drawString(64, 20, formatCurrency(price));
? display.setFont(ArialMT_Plain_16);
//? display.setTextAlignment(TEXT_ALIGN_CENTER);
//? display.drawString(64, 48, " 1h:" + String(response.percent_change_1h) + "%");
? display.setTextAlignment(TEXT_ALIGN_CENTER);
? display.drawString(64, 48, "24h: " + String(response.percent_change_24h) + "%");
? display.display();
}
void displayMessage(String message){
? display.clear();
? display.setFont(ArialMT_Plain_10);
? display.setTextAlignment(TEXT_ALIGN_LEFT);
? display.drawStringMaxWidth(0, 0, 128, message);
? display.display();
}
String formatCurrency(float price) {
? String formattedCurrency = CURRENCY_SYMBOL;
? int pointsAfterDecimal = 6;
? if (price > 100) {
? ? pointsAfterDecimal = 2;
? } else if (price > 1) {
? ? pointsAfterDecimal = 4;
? }
? formattedCurrency.concat(String(price, pointsAfterDecimal));
? return formattedCurrency;
}
bool loadDataForHolding(int index) {
? int nextIndex = getNextIndex();
? if (nextIndex > -1 ) {
? ? holdings[index].lastResponse = api.GetTickerInfo(holdings[index].tickerId, CURRENCY);
? ? return holdings[index].lastResponse.error == "";
? }
? return false;
}
void loop() {
? unsigned long timeNow = millis();
? if ((timeNow > screenChangeDue))? {
? ? currentIndex = getNextIndex();
? ? if (currentIndex > -1) {
? ? ? if (loadDataForHolding(currentIndex)) {
? ? ? ? displayHolding(currentIndex);
? ? ? } else {
? ? ? ? displayMessage(F("Error loading data."));
? ? ? }
? ? } else {
? ? ? displayMessage(F("No funds to display. Edit the setup to add them"));
? ? }
? ? screenChangeDue = timeNow + screenChangeDelay;
? }
}
