Desk Air Quality Buddy

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_GC9A01A.h>
#include <DHT.h>
#include <driver/i2s.h>

constexpr int TFT_CS = 7;
constexpr int TFT_DC = 2;
constexpr int TFT_SCK = 4;
constexpr int TFT_MOSI = 6;
constexpr int MIC_SCK = 10;
constexpr int MIC_WS = 20;
constexpr int MIC_SD = 21;
constexpr int DHT_PIN = 3;
constexpr int DHT_TYPE = DHT11;
constexpr float MIC_FULL_SCALE = 2147483647.0f;
constexpr unsigned long CLIMATE_INTERVAL_MS = 2000;
constexpr float HIGH_TEMPERATURE_C = 30.0f;
constexpr float HIGH_HUMIDITY_PERCENT = 70.0f;

Adafruit_GC9A01A display(TFT_CS, TFT_DC, -1);
DHT dht(DHT_PIN, DHT_TYPE);

int lastSoundDbfs = 999;
bool alertActive = false;
float lastTemperature = NAN;
float lastHumidity = NAN;
unsigned long lastClimateReadMs = 0;

void drawStaticUi() {
  display.fillScreen(GC9A01A_BLACK);
  display.drawRoundRect(6, 6, 228, 228, 18, GC9A01A_DARKGREY);

  display.fillRoundRect(20, 16, 200, 28, 12, GC9A01A_CYAN);
  display.setTextColor(GC9A01A_BLACK);
  display.setTextSize(2);
  display.setCursor(57, 23);
  display.print("DESKBUDDY");

  display.drawRoundRect(18, 54, 98, 40, 9, GC9A01A_DARKGREY);
  display.drawRoundRect(124, 54, 98, 40, 9, GC9A01A_DARKGREY);
  display.setTextSize(1);
  display.setTextColor(GC9A01A_LIGHTGREY);
  display.setCursor(31, 61);
  display.print("TEMP");
  display.setCursor(138, 61);
  display.print("HUMIDITY");

  display.drawRoundRect(18, 104, 204, 67, 9, GC9A01A_DARKGREY);
  display.setTextColor(GC9A01A_CYAN);
  display.setCursor(91, 111);
  display.print("ALERTS");

  display.drawRoundRect(18, 180, 204, 43, 9, GC9A01A_DARKGREY);
}

void drawSoundLevel(int dbfs) {
  display.fillRoundRect(24, 187, 192, 29, 6, GC9A01A_BLACK);
  display.setTextSize(1);
  display.setTextColor(GC9A01A_LIGHTGREY);
  display.setCursor(31, 191);
  display.print("MIC");
  display.setTextColor(dbfs > -25 ? GC9A01A_YELLOW : GC9A01A_CYAN);
  display.setCursor(31, 202);
  display.print(dbfs);
  display.print(" dBFS");
  int barWidth = map(constrain(dbfs, -80, 0), -80, 0, 0, 104);
  display.drawRoundRect(101, 198, 106, 10, 5, GC9A01A_DARKGREY);
  if (barWidth > 0) {
    uint16_t color = dbfs > -25 ? GC9A01A_RED : (dbfs > -45 ? GC9A01A_YELLOW : GC9A01A_GREEN);
    display.fillRoundRect(102, 199, barWidth, 8, 4, color);
  }
}

void drawAlertStatus(bool active, float temperature, float humidity) {
  display.fillRect(28, 127, 184, 35, GC9A01A_BLACK);
  display.setTextSize(1);
  if (!active) {
    display.setTextColor(GC9A01A_GREEN);
    display.setCursor(67, 140);
    display.print("ROOM LOOKS GOOD");
    return;
  }
  display.setTextColor(GC9A01A_YELLOW);
  display.setCursor(44, 132);
  if (temperature >= HIGH_TEMPERATURE_C && humidity >= HIGH_HUMIDITY_PERCENT) {
    display.print("WARM AND HUMID");
  } else if (temperature >= HIGH_TEMPERATURE_C) {
    display.print("ROOM IS WARM");
  } else {
    display.print("ROOM IS HUMID");
  }
  display.setTextColor(GC9A01A_LIGHTGREY);
  display.setCursor(55, 150);
  display.print("CHECK THE ROOM");
}

void drawClimate(float temperature, float humidity) {
  display.fillRect(25, 72, 190, 17, GC9A01A_BLACK);
  if (isnan(temperature) || isnan(humidity)) {
    display.setTextSize(1);
    display.setTextColor(GC9A01A_ORANGE);
    display.setCursor(66, 78);
    display.print("DHT11 WAITING");
    return;
  }
  display.setTextSize(2);
  display.setTextColor(GC9A01A_WHITE);
  display.setCursor(30, 74);
  display.print(temperature, 0);
  display.print("C");
  display.setCursor(143, 74);
  display.print(humidity, 0);
  display.print("%");
}

void updateClimateIfDue() {
  if (millis() - lastClimateReadMs < CLIMATE_INTERVAL_MS) return;
  lastClimateReadMs = millis();
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  if (isnan(temperature) || isnan(humidity)) return;
  bool newAlertActive = temperature >= HIGH_TEMPERATURE_C || humidity >= HIGH_HUMIDITY_PERCENT;
  if (isnan(lastTemperature) || isnan(lastHumidity) || temperature != lastTemperature || humidity != lastHumidity) {
    drawClimate(temperature, humidity);
    lastTemperature = temperature;
    lastHumidity = humidity;
  }
  if (newAlertActive != alertActive) {
    drawAlertStatus(newAlertActive, temperature, humidity);
  }
  alertActive = newAlertActive;
}

void setupMicrophone() {
  i2s_config_t config = {};
  config.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX);
  config.sample_rate = 16000;
  config.bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT;
  config.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT;
  config.communication_format = I2S_COMM_FORMAT_I2S;
  config.dma_buf_count = 4;
  config.dma_buf_len = 128;
  i2s_driver_install(I2S_NUM_0, &config, 0, nullptr);
  i2s_pin_config_t pins = {};
  pins.bck_io_num = MIC_SCK;
  pins.ws_io_num = MIC_WS;
  pins.data_out_num = I2S_PIN_NO_CHANGE;
  pins.data_in_num = MIC_SD;
  i2s_set_pin(I2S_NUM_0, &pins);
}

int readSoundDbfs() {
  int32_t samples[128];
  size_t bytesRead = 0;
  i2s_read(I2S_NUM_0, samples, sizeof(samples), &bytesRead, portMAX_DELAY);
  int sampleCount = bytesRead / sizeof(int32_t);
  if (sampleCount == 0) return -96;

  double sumSquares = 0.0;
  for (int i = 0; i < sampleCount; i++) {
    float normalized = (float)samples[i] / MIC_FULL_SCALE;
    sumSquares += normalized * normalized;
  }
  float rms = sqrtf((float)(sumSquares / sampleCount));
  float dbfs = 20.0f * log10f(fmaxf(rms, 0.00001585f));
  return (int)roundf(fmaxf(-96.0f, fminf(0.0f, dbfs)));
}

void setup() {
  dht.begin();
  setupMicrophone();
  SPI.begin(TFT_SCK, -1, TFT_MOSI, TFT_CS);
  display.begin();
  display.setRotation(0);
  drawStaticUi();
  drawClimate(NAN, NAN);
  drawAlertStatus(false, NAN, NAN);
  lastClimateReadMs = millis() - CLIMATE_INTERVAL_MS;
  updateClimateIfDue();
  lastSoundDbfs = readSoundDbfs();
  drawSoundLevel(lastSoundDbfs);
}

void loop() {
  updateClimateIfDue();
  int soundDbfs = readSoundDbfs();
  if (soundDbfs != lastSoundDbfs) {
    drawSoundLevel(soundDbfs);
    lastSoundDbfs = soundDbfs;
  }
}