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Thermostat + Gateway

The Thermostat sample showed how to implement a thermostat controller using local data. This part 2 of the sample shows how to connect the device to a cloud gateway and configure the desired temperature from the cloud.

Development Gateway​

Start by setting up a Development Gateway and connecting the ESP to it.

Telemetry​

Just like any web or desktop app, a DeviceScript app can be instrumented with telemetry to get insights into how it is behaving.

For example, we instrument the code to notify the cloud whenever the relay is enabled or disabled.

import { pins } from "@dsboard/adafruit_qt_py_c3"
import { Temperature } from "@devicescript/core"
import { ewma, tap, auditTime, levelDetector } from "@devicescript/observables"
import { startRelay } from "@devicescript/servers"
import { trackEvent } from "@devicescript/cloud"

const thermometer = new Temperature()
const t_ref = 68 // degree F
const relay = startRelay({
    pin: pins.A0_D0,
})

thermometer.reading
    .pipe(
        tap(t_raw => console.data({ t_raw })),
        ewma(0.9),
        tap(t_ewma => console.data({ t_ewma })),
        auditTime(5000),
        tap(t_audit => console.data({ t_audit })),
        levelDetector(t_ref - 1, t_ref + 1),
        tap(level => console.data({ level }))
    )
    .subscribe(async level => {
        const enabled = await relay.enabled.read()
        const newEnabled = level < 0 ? true : level > 0 ? false : enabled
        await relay.enabled.write(newEnabled)
        if (enabled !== newEnabled)
            await trackEvent("relay.change", {
                properties: { active: newEnabled ? "on" : "off" },
            })
    })

Environment variables​

If you connect the ESP to the Development Gateway, you can use environment variables configured in the cloud rather constants in the code.

The environment function from @devicescript/cloud downloads and caches the environment variables from the cloud.

import { pins } from "@dsboard/adafruit_qt_py_c3"
import { Temperature } from "@devicescript/core"
import { ewma, tap, auditTime, levelDetector } from "@devicescript/observables"
import { startRelay } from "@devicescript/servers"
import { environment } from "@devicescript/cloud"

const thermometer = new Temperature()
const relay = startRelay({
    pin: pins.A0_D0,
})
const env = await environment<{ t_ref: number }>({ t_ref: 68 })
const { t_ref } = await env.read()

thermometer.reading
    .pipe(
        tap(t_raw => console.data({ t_raw })),
        ewma(0.9),
        tap(t_ewma => console.data({ t_ewma })),
        auditTime(5000),
        tap(t_audit => console.data({ t_audit })),
        levelDetector(t_ref - 1, t_ref + 1),
        tap(level => console.data({ level }))
    )
    .subscribe(async level => {
        if (level < 0) await relay.enabled.write(true)
        else if (level > 0) await relay.enabled.write(false)
        console.data({ relay: await relay.enabled.read() })
    })

Environment updates​

The environment variables can be updated in the cloud at any time. We can track the changes and update the relay accordingly.

import { pins } from "@dsboard/adafruit_qt_py_c3"
import { Temperature } from "@devicescript/core"
import {
    ewma,
    tap,
    auditTime,
    levelDetector,
    Subscription,
} from "@devicescript/observables"
import { startRelay } from "@devicescript/servers"
import { environment } from "@devicescript/cloud"

const thermometer = new ds.Temperature()
const relay = startRelay({
    pin: pins.A0_D0,
})
const env = await environment<{ t_ref: number }>({ t_ref: 68 })
let sub: Subscription
const controlTemperature = async () => {
    // cleanup previous loop
    if (sub) sub.unsubscribe()

    // start new control loop
    const { t_ref } = await env.read()
    sub = thermometer.reading
        .pipe(
            tap(t_raw => console.data({ t_raw })),
            ewma(0.9),
            tap(t_ewma => console.data({ t_ewma })),
            auditTime(5000),
            tap(t_audit => console.data({ t_audit })),
            levelDetector(t_ref - 1, t_ref + 1),
            tap(level => console.data({ level }))
        )
        .subscribe(async level => {
            if (level < 0) await relay.enabled.write(true)
            else if (level > 0) await relay.enabled.write(false)
            console.data({ relay: await relay.enabled.read() })
        })
}

// hightline-next-line
env.subscribe(controlTemperature)
await controlTemperature()