index.js

const axios = require('axios');

const query_path = "/cgi-bin/json_query?jsoncallback=";

const timeout = 10000;
const interval = 15;	// Minutes
const debug = false;

var Service;
var Characteristic;

module.exports = function (homebridge) {
    Service = homebridge.hap.Service;
    Characteristic = homebridge.hap.Characteristic;
    homebridge.registerAccessory("homebridge-epson-iprojection", "Epson iProjection", EpsonProjector);
};


function EpsonProjector(log, config) {
    this.log = log;
    this.ipAddress = config["ipAddress"];
    this.model = config["model"] === undefined ? "" : config["model"];
    this.serial = config["serial"] === undefined ? "" : config["serial"];
    this.name = config["name"];
    this.timeout = config["timeout"] === undefined ? timeout : config["timeout"];
		this.refreshInterval = config["refreshInterval"] === undefined ? interval * 60000 : config["refreshInterval"] * 60000;
    this.debug = config["debug"] === undefined ? debug : config["debug"];

    this.state = false;	// Track the power state

		this.referer = "http://" + this.ipAddressAddress + "/cgi-bin/webconf";
		this.api = axios.create({
			headers: {'Referer': this.referer}
		});

		this.informationService = new Service.AccessoryInformation();
		this.informationService
				.setCharacteristic(Characteristic.Manufacturer, "Epson")
				.setCharacteristic(Characteristic.Model, this.model)
				.setCharacteristic(Characteristic.SerialNumber, this.serial);
		this.switchService = new Service.Switch(this.name);
		this.switchService
				.getCharacteristic(Characteristic.On)
						.on('set', this.setPowerState.bind(this));

		this.wait = null;
		this.timer = null;
		this.poll()
}

EpsonProjector.prototype = {

	updateUI: async function () {
		setTimeout( () => {
			this.switchService.getCharacteristic(Characteristic.On).updateValue(this.state);
			this.log('Updated Characteristic value to %s', this.state);
		}, 100)
	},

	free: async function () {
		if(this.wait) clearTimeout(this.wait);
		this.wait = null;
		this.poll();;
	},

	poll: async function () {
		if(this.timer) clearTimeout(this.timer);
		this.timer = null;
		if(!this.wait) {
		
			try {	 
				const resp = await this.api.get('http://' + this.ipAddress + query_path + 'PWR?')
				.catch(err => {
					this.log.error('Error getting power state %s',err)
				});

				// this.state = parseInt(resp.data.projector.feature.reply);
				this.state = resp.data.projector.feature.reply === "01";
				this.updateUI();
				if (this.debug) {
					this.log("http://" + this.ipAddress + query_path + "PWR?");
					this.log("Projector response: " + resp.data.projector.feature.reply + " =", this.state);
				}
			} catch(err) {
					this.log.error('Error getting power state %s',err)
			}
		}
		this.timer = setTimeout(this.poll.bind(this), this.refreshInterval);
	},

	setPowerState: async function(powerOn, callback) {
		if (!this.wait) {
			this.state = powerOn;
			this.updateUI();
			if(this.timer) clearTimeout(this.timer)
			this.timer = null
			let command;
			if (powerOn) {
				command = "PWR ON";
			} else {
				command = "PWR OFF";
			}
			if (this.debug) {
				this.log('powerOn = %s', powerOn);
				this.log("http://" + this.ipAddress + query_path + command);
			}
			callback(null);
			this.wait = setTimeout(this.free.bind(this), powerOn === true ? 60000 : 300000);
			try {
				const resp = await this.api({
					method: 'get',
					url: 'http://' + this.ipAddress + query_path + command,
					timeout: 16000
				}).catch(err => {					
//					this.log.error('Error setting power state %s',err)
				});
			}catch(err) {
				this.log.error('Error setting powerState %s',err)
			}
		}
	},

	getServices: function () {
		return [this.informationService, this.switchService];
	}
};