前言
2018年开始投资比特币等数字货币，不料一路暴跌，血亏之后，卸载所有 app 。
计划屯币到2020年，等比特币再次减半，希望到时能回本或者小赚。
总得做点什么纪念这次失败的炒币行动，作为一个程序员，只能用代码来表示了。
决定做一个简单的比特币示价器，随时随地可以查看价格。
前期准备
硬件部分
- ESP8266 NodeMcu WIFI
这是一款类似 Arduino 一样操作硬件IO的设备，支持Nodejs 类似语法，而且集成了一个超低成本的 wifi 模块。非常适合我们用来做一些小玩意。
- 0.96寸OLED显示屏
一个非常小的单色显示器，不支持中文显示，优点仅仅是便宜！
- 母对母杜邦线
为了连接芯片和显示器用的。
软件部分
由于我用的是 macbook 所以，下载地址都是 mac 版本的。其他平台请到官网下载相应版本
- Arduino
下载地址：https://www.arduino.cc/en/Main/Software
- CH340/CH341的USB转串口驱动程序
下载地址：http://www.wch.cn/download/CH341SER_MAC_ZIP.html
连接方式：
代码
/*******************************************************************
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 密码"; // 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;
}
}
