Shelly Plus Plug S script to automatically turn off the plug after 3D printing has finished and cooling delay has elapsed

printer_monitor.js

// This script detects printing start and stop events based on power consumption.
// When the stop event is detected, it waits for 15 minutes to enable printer to cool down and shutdown event is triggered.

let CONFIG = {
    cooldownDelay: 15 * 60 * 1000, // 15 minutes
    idlePowerMax: 12, // 12 Watts (in reality 7-8W) 
};

let cooldownTimer = null;
let printingStarted = false;

Shelly.addStatusHandler(function (event, user_data) {
    //print(JSON.stringify(event));
    if (typeof event.delta.apower !== "undefined") {
        let currentPower = event.delta.apower;
        if (currentPower > CONFIG.idlePowerMax && printingStarted === false) {
            print("Printing has started");
            printingStarted = true;
            stopTimer();
        }

        if (currentPower < CONFIG.idlePowerMax && printingStarted) {
            print("Printing has ended");
            printingStarted = false;
            startDelayedShutdown();
        }
    }
}, null);

function startDelayedShutdown() {
    print("Starting delayed switch shutdown");
    cooldownTimer = Timer.set(
        CONFIG.cooldownDelay,
        false,
        function (ud) {
            turnOffSwitch();
        },
        null
    );
}

function stopTimer() {
    if (cooldownTimer) {
      Timer.clear(cooldownTimer);
      cooldownTimer = null;
    }
}

function turnOffSwitch() {
    print("Switch shutdown");
    Shelly.call(
        "switch.set",
        { id: 0, on: false },
        function (result, code, msg, ud) { },
        null
    );
}