espruino-iss-notifier.js

// Wifi Credentials
const WIFI_NAME = "YOURSSID";
const WIFI_PASS = "YOURPASS";

// Your location latitude and longitude
const lat = 'YOURLAT';
const lon = 'YOURLON';

// Required libs
const http = require("http");
const np = require("neopixel");


// Variable to store the time
let now;
// Variable to store ISS pass info
let iss;
// Variable to set the interval so we can clear it
let intervalId;

// Setup Wifi Shim according to instructions found here:
// https://www.espruino.com/ESP8266
digitalWrite(B9, 1); // enable on Pico Shim V2
Serial2.setup(115200, { rx: A3, tx: A2 });

// Turn LED off
np.write(B5, [0,0,0]);

/**
 * Connect to WIFI
 */
var wifi = require("ESP8266WiFi_0v25").connect(Serial2, function (err) {
  if (err) throw err;
  console.log("Connecting to WiFi");

  wifi.connect(WIFI_NAME, WIFI_PASS, err => {
    if (err) throw err;
    console.log("Connected");
    // Once we have connected, set the UTC time
    setTime();
  });

});

/**
 * Set the UTC time to sync with the ISS API
 */
function setTime() {
  console.log("Setting Time");
  http.get('http://worldclockapi.com/api/json/utc/now', res => {
    let contents = '';
    res.on("data", data => contents += data);
    res.on("close", () => {
      let timeJson = JSON.parse(contents);
      now = new Date(timeJson.currentDateTime);
      // Now we have set the time, let's get the ISS pass data
      fetchData();
    });
  }).on("error", e => console.log("Error getting time: ", e));
}

/**
 * Fetch the ISS Pass Data
 */
function fetchData() {
  console.log("Fetching Data");

  let url = `http://api.open-notify.org/iss-pass.json?lat=${lat}&lon=${lon}`;
  
  http.get(url, res => {
    let contents = '';
    res.on("data", data => contents += data);
    res.on("close", () => {
      try {
        iss = JSON.parse(contents);
        // If we didn't have an error, all is good
        if (iss.hasOwnProperty('message') && iss.message == 'success') {
          // Calculate the interval between request time and next rise
          let interval = (iss.response[0].risetime * 1000) - now.getTime();
          let duration = iss.response[0].duration;
          showDebug(iss);
          // Set the timeout function (multiply the duration by 1k to convert to ms)
          setTimeout(flashLED, interval, duration * 1000);
        } else {
          // Something went wrong, we'll try again in 30 seconds
          setTimeout(fetchData, 30 * 1000);
        }
      } catch (e) {
        // There was an error parsing the data, let's try again in 30 seconds
        console.log("ERROR parsing ISS json", e);
        setTimeout(fetchData, 30 * 1000);
      }
    });
  }).on("error", (e) => {
    // There was an error fetching the data, let's try again in 30 seconds
    console.log("ERROR fetching data: ", e);
    setTimeout(fetchData, 30 * 1000);
  });
}

/** 
 * Flash the LED to notify us of the 
 */
function flashLED(duration) {
  console.log('ISS Overhead!');
  let state = true;
  intervalId = setInterval(() => {
    if(state) np.write(B5, [100, 10, 10])
    else np.write(B5, [10, 30, 100])
    state = !state
  }, 1000);
  setTimeout(() => {
    // Clear the interval
    clearInterval(intervalId);
    // Turn off LED
    np.write(B5, [0,0,0]);
    // Fetch more data!
    setTime();
  }, duration);
}

/**
 * Show debug information in terminal
 */
function showDebug() {
  console.log("Current time: ", now);
  console.log("Next rise: ", new Date(iss.response[0].risetime * 1000));
  console.log("Pass duration: ", iss.response[0].duration + " seconds. Or " + iss.response[0].duration / 60 + " minutes. ");
}