YouTube API to MAX7219 display Widget

YTChanViewCounter.ino

// YouTube Channel View Counter
// Kenneth Finnegan, 2017
//
// Given a WiFi SSID + password, and YouTube API key + channel ID, displays the
// current total views count on an attached MAX7219 eight digit display

#include <YoutubeApi.h>
#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>

//------- Replace the following! ------
char ssid[] = "WIFISSIF";       // your network SSID (name)
char password[] = "WIFIPASSWORD";  // your network key
#define API_KEY "INSERTYOURAPPSAPIKEYHERE"  // your google apps API Token
#define CHANNEL_ID "INSERTCHANNELIDHERE" // makes up the url of channel

// This depends on which pins you've wired the MAX7219 driver to.
#define DISP_CS 12
#define DISP_CLK  14
#define DISP_DATA 13


WiFiClientSecure client;
YoutubeApi api(API_KEY, client);

// The total channel view count is updated very rarely (daily?) so we don't need to check regularly
unsigned long api_mtbs = 5 * 60 * 1000; // Desired update interval in milliseconds
unsigned long api_lasttime = 0-api_mtbs;   //last time api request has been done
  // Note that we're pre-loading the "last update" variable to an interval before zero so the
  // display updates immediately on boot

////////////////////////////
// DISPLAY DRIVER SECTION //
////////////////////////////

// Soft implementation of SPI because I don't even know if the ESP-12 has SPI hardware available
// [TODO: insert rant about how much Arduino platform documentation sucks these days]
// This only sends eight bits, which is half a MAX7219 command
void disp_send(uint8_t data) {
  int i;
  for (i=0; i<8; i++) {
    // Send the most significant bit first
    digitalWrite(DISP_DATA, !!(data & (1<<(7-i))));
    delay(1); // These delays might not be needed, but I like the visual effect of the slow update
    // Then toggle the clock line
    digitalWrite(DISP_CLK, HIGH);
    delay(1);
    digitalWrite(DISP_CLK, LOW);
    delay(1);
  }
}

// Sends two bytes, the register select and the payload for that data
// See the datasheet for the full memory map:
// https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf
void disp_cmd(uint8_t reg, uint8_t data) {
  digitalWrite(DISP_CS, LOW);
  disp_send(reg);
  disp_send(data);
  digitalWrite(DISP_CS, HIGH);
}

// Given an integer, write it to the display
void disp_number(int data) {
  int i;
  for (i=1; i<=8; i++) {
    int output = data % 10;
    // Turn on the decimal place at 4 and 7 to make it easier to read
    if (i == 4 || i == 7) output |= 0x80;
    // Blank leading zeros if we've run out of data and we're not the first digit
    if (data == 0 && i != 1) output = 0x0F;
    disp_cmd(i,output);
    data = data / 10;
  }
}

// When we aren't working, display "00000000" then "--HELP--"
void disp_error() {
  int i;
  for (i=8; i>0; i--) {
    disp_cmd(i,0x00);
  }
    
  disp_cmd(0x08,0x0A); // -
  disp_cmd(0x07,0x0A); // -
  disp_cmd(0x06,0x0C); // H
  disp_cmd(0x05,0x0B); // E
  disp_cmd(0x04,0x0D); // L
  disp_cmd(0x03,0x0E); // P
  disp_cmd(0x02,0x0A); // -
  disp_cmd(0x01,0x0A); // -
}


////////////////////////////////
// MAIN SETUP AND MASTER LOOP //
////////////////////////////////

void setup() {

  Serial.begin(115200);

  // Set up the MAX7219 display and load the command registers
  pinMode(DISP_CS, OUTPUT);
  pinMode(DISP_CLK, OUTPUT);
  pinMode(DISP_DATA, OUTPUT);
  disp_cmd(0x0C,0x01); // Leave shutdown
  delay(30);
  disp_cmd(0x0F,0x00); // Leave display test
  delay(30);
  disp_cmd(0x09,0xFF); // Use B code on all eight digits
  delay(30);
  disp_cmd(0x0A,0x02); // Set software intensity 0-15
  delay(30);
  disp_cmd(0x0B,0x07); // Scan all eight digits (blank individual digits with 0xF)
  delay(30);
  disp_error();

  // 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);


  
}

void loop() {

  if (millis() - api_lasttime > api_mtbs)  {
    Serial.println("Trying to query API");
    if(api.getChannelStatistics(CHANNEL_ID)) {
      Serial.println("---------Stats---------");
      Serial.print("Subscriber Count: ");
      Serial.println(api.channelStats.subscriberCount);
      Serial.print("View Count: ");
      Serial.println(api.channelStats.viewCount);
      Serial.print("Comment Count: ");
      Serial.println(api.channelStats.commentCount);
      Serial.print("Video Count: ");
      Serial.println(api.channelStats.videoCount);
      Serial.println("------------------------");

      disp_number(api.channelStats.viewCount);

      api_lasttime = millis();
    } else {
      // Something went wrong, so try again in 30s
      Serial.println("YOUTUBE API ERROR!");
      disp_error();
      api_lasttime += 30 * 1000;
    }
  }
}