micro:bit v2 controller for RIGID Micro DC Aircon https://www.rigidhvac.com/micro-dc-aircon-12v

main.cpp

#include <algorithm>
#include <cstdio>
#include "MicroBit.h"

static MicroBit uBit;
static int targetTemp = 35;
static int showCount;

static void setPower(int newPeriod, NRF52Pin &pin)
{
    static int curPeriod = 0;

    // to minimize the noise, change the variables only when we have to
    if (curPeriod == newPeriod)
        return;

    pin.setAnalogValue(511);
    pin.setAnalogPeriodUs(newPeriod);

    curPeriod = newPeriod;
}

static void showState()
{
    showCount = 3;
}

static void onButtonA(MicroBitEvent)
{
    if (showCount > 0 && targetTemp > 20)
        --targetTemp;
    showState();
}

static void onButtonB(MicroBitEvent)
{
    if (showCount > 0 && targetTemp < 35)
        ++targetTemp;
    showState();
}

// when idle for 10 minutes, report that using sound tone
static void reportIdle(int powerLevel)
{
    static unsigned long lastOnAt = 0;
    unsigned long now = uBit.systemTime();

    if (powerLevel != 0)
        goto UpdateNow;

    if (now - lastOnAt < 10 * 60 * 1000)
        return;

    uBit.io.speaker.setAnalogValue(0);
    static const unsigned tones[] = {1000000 / 440, 1000000 / 494, 1000000 / 554, 1000000 / 587, 1000000 / 659};
    for (size_t i = 0; i < sizeof(tones) / sizeof(tones[0]); ++i) {
        uBit.io.speaker.setAnalogPeriodUs(tones[i]);
        uBit.io.speaker.setAnalogValue(511);
        uBit.sleep(250);
    }
    uBit.sleep(500);
    uBit.io.speaker.setAnalogValue(0);

UpdateNow:
    // report after predefined seconds
    lastOnAt = now;
}

int main()
{
    uBit.init();
    uBit.messageBus.listen(MICROBIT_ID_BUTTON_A, MICROBIT_BUTTON_EVT_CLICK, onButtonA);
    uBit.messageBus.listen(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonB);

    MicroBitThermometer thermo;

    showState();

    while(1) {
        // reported temp is 1~2 degrees higher than the actual value
        int currentTemp = thermo.getTemperature() - 1;

        int powerLevel = currentTemp - targetTemp + 1;
        powerLevel = max(min(powerLevel, 3), 0);

#if 1 /* for pin 0 */
        static const unsigned periods[] = {1000000 / 400, 1000000 / 2000, 1000000 / 6000, 1000000 / 10000};
        setPower(periods[powerLevel], uBit.io.P0);
#else /* to test with speaker */
        static const unsigned periods[] = {1000000 / 110, 1000000 / 220, 1000000 / 440, 1000000 / 880};
        setPower(periods[powerLevel], uBit.io.speaker);
#endif

        if (showCount > 0) {
            char buf[32];
            sprintf(buf, "%d%c %d", targetTemp, "oLmh"[powerLevel], currentTemp);
            uBit.display.scroll(buf);
            --showCount;
        }

        reportIdle(powerLevel);

        uBit.sleep(1000);
    }
}