esp-air-monitor/main/main.c

/**
 * Author: Arthur Roberts (c) 2023
 *
 * License: GPLv3+
 */

#include "dht22.h"
#include "sdkconfig.h"
#include "wifi.h"
#include "esp_log.h"
#include "esp_sntp.h"
#include "freertos/FreeRTOS.h"
#include "freertos/projdefs.h"
#include "freertos/task.h"
#include "nvs_flash.h"
#include "portmacro.h"
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

static const char* TAG = "YASPAM";

static volatile bool run_dht = true;
static volatile bool run_pms5003 = true;

static TaskHandle_t dht22_handle = NULL;
static TaskHandle_t pms5003_handle = NULL;

typedef struct {
  uint8_t myt_sec;    // 0 -> 61
  uint8_t myt_min;    // 0 -> 69
  uint8_t myt_hour;   // 0 -> 23
  uint8_t myt_day;    // 1 -> 31
  uint8_t myt_month;  // 0 -> 11 !!
  uint8_t myt_year;   // years since 1900
} my_time;

#ifdef CONFIG_PMS5003_ENABLED
#include "pms5003.h"

void
read_from_pms5003()
{
  while (run_pms5003) {
    // TODO: actually collect some data
    ESP_LOGI(TAG, "Got PMS5003 data!");
    // TODO: Write the data out somewhere
    vTaskDelay(pdMS_TO_TICKS(CONFIG_PMS5003_PERIOD_POLL));
  }
}
#endif /* CONFIG_PMS5003_ENABLED */

#ifdef CONFIG_DHT22_ENABLED
#include "dht22.h"

typedef struct {
  deci_percent rh;
  deci_degrees_c temp;
  my_time time;
} my_dht22_data;

my_dht22_data latest_datapoint;

my_dht22_data ten_minute_rolling_average;
uint32_t num_samples_last_ten_mins = 0;

void read_from_dht22() {
  while (run_dht) {
    // Data reading is based on time, so need to block interrups etc
    // I _think_ these are freeRTOS task interrupts - I wonder if
    // I need to also block ESP interrupts? Should I even do that?
    portDISABLE_INTERRUPTS();
    int ret = dht22_read();
    portENABLE_INTERRUPTS();
    if (ret != DHT22_OK) {
      dht22_handle_error(ret);
    } else {
      latest_datapoint.temp = dht22_temperature();
      latest_datapoint.rh = dht22_relative_humidity();

      if (has_ntp_time_obtained_once()) {
        // I _think_ I only want to be doing that rolling average and saving if/when
        // we've got an actual time to do that with. I think that'd avoid some weird
        // bugs (time changing from 1970 -> current time within a 10 min period)
        time_t epoch;
        time(&epoch);
        struct tm *timeinfo = localtime(&epoch);

        // There must be a better way - I couldn't figure out how to do it nicely all at once
        latest_datapoint.time.myt_sec   = timeinfo->tm_sec;
        latest_datapoint.time.myt_min   = timeinfo->tm_min;
        latest_datapoint.time.myt_hour  = timeinfo->tm_hour;
        latest_datapoint.time.myt_day   = timeinfo->tm_mday;
        latest_datapoint.time.myt_month = timeinfo->tm_mon;
        latest_datapoint.time.myt_year = timeinfo->tm_year;

        if (num_samples_last_ten_mins == 0) {
          ten_minute_rolling_average.rh = latest_datapoint.rh;
          ten_minute_rolling_average.temp = latest_datapoint.temp;
        } else {
          ten_minute_rolling_average.rh +=
              (latest_datapoint.rh - ten_minute_rolling_average.rh) /
              num_samples_last_ten_mins;
          ten_minute_rolling_average.temp +=
            (latest_datapoint.temp - ten_minute_rolling_average.temp) / num_samples_last_ten_mins;
        }
        num_samples_last_ten_mins += 1;

        // This should be: if (number of samples in 10 mins taken)
        // This _will_ break if sampled too quickly, because we'll have more samples per 10 minutes
        // than can be stored in a uint32 - I'll calculate what that is and perhaps raise a compile
        // error if too high.
        if (num_samples_last_ten_mins >=
            (CONFIG_DHT22_PERIOD_POLL * 1000 * 60 * 10)) {
          num_samples_last_ten_mins = 0;
          // TODO: Write the data out somewhere - into RAM maybe
          // TODO: maybe push the data somewhere - or put a flag up that data can be pushed
          //  ^ could do a cute Semaphore thingy here - I don't think I've actually used one before
        }
      }
    }
    vTaskDelay(pdMS_TO_TICKS(CONFIG_DHT22_PERIOD_POLL));
  }
}
#endif /* CONFIG DHT22_ENABLED */

void
app_main(void)
{
  esp_err_t ret = nvs_flash_init();
  if (ret == ESP_ERR_NVS_NO_FREE_PAGES ||
      ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
    ESP_ERROR_CHECK(nvs_flash_erase());
    ret = nvs_flash_init();
  }
  ESP_ERROR_CHECK(ret);

#ifdef CONFIG_DHT22_ENABLED
  xTaskCreate(read_from_dht22,
              "DHT22",
              4 * 1024, // honestly I have _no_ idea
              NULL,
              5,     // no idea either
              &dht22_handle);
  
#endif /* CONFIG_DHT22_ENABLED */

#ifdef CONFIG_PMS5003_ENABLED
  
  xTaskCreate(read_from_pms5003,
              "PMS5003",
              4 * 1024, // honestly I have _no_ idea
              NULL,
              5,     // no idea either
              &pms5003_handle);
  
#endif /* CONFIG_PMS5003_ENABLED */

  start_wifi();
}