Files
SerreklimaatSensor/main/main.c
Douwe Ravers dfaff67fab Final version 1:
reads data every 15 minutes
saves data persistently every 24h
writes out the contents every measure.
goes in deep sleep so very low power consumption. (reason removal task system)
2026-04-30 09:06:49 +02:00

312 lines
8.8 KiB
C

#include <stdint.h>
#include <stdio.h>
#include <inttypes.h>
#include <locale.h>
#include <time.h>
#include <string.h>
#include <sys/time.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"
#include "esp_chip_info.h"
#include "esp_flash.h"
#include "esp_system.h"
#include "esp_timer.h"
#include "esp_spiffs.h"
#include "esp_sleep.h"
#include "driver/gpio.h"
#include "driver/rtc_io.h"
#define PRINT_DEBUG false
#define WIPE_MEMORY false
#define DHT11_GPIO 0
#define BLINK_GPIO 8
#define DATA_BUFFER_SIZE 100
typedef struct {
char timestamp[64];
float humidity;
float temperature;
} SensorData;
// RTC buffer to store time
RTC_DATA_ATTR time_t rtc_unix_time = 0;
RTC_DATA_ATTR bool rtc_time_initialized = false;
// RTC buffer to store measurements
RTC_DATA_ATTR SensorData rtc_measurement_buffer[DATA_BUFFER_SIZE];
RTC_DATA_ATTR int rtc_buffer_index = 0;
// ############### Base Setup ###############
void set_system_time() {
if (!rtc_time_initialized) {
// First boot: use compile time
struct tm tm = {0};
char month[4];
int day, year, hour, min, sec;
sscanf(__DATE__, "%3s %d %d", month, &day, &year);
sscanf(__TIME__, "%d:%d:%d", &hour, &min, &sec);
const char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
for (int i = 0; i < 12; i++) {
if (strcmp(month, months[i]) == 0) {
tm.tm_mon = i;
break;
}
}
tm.tm_mday = day;
tm.tm_year = year - 1900;
tm.tm_hour = hour;
tm.tm_min = min;
tm.tm_sec = sec;
tm.tm_isdst = -1;
rtc_unix_time = mktime(&tm);
rtc_time_initialized = true;
}
// Set system time from RTC
struct timeval tv = { .tv_sec = rtc_unix_time, .tv_usec = 0 };
settimeofday(&tv, NULL);
}
void get_current_time(char* time_string, size_t size) {
time_t now;
struct tm timeinfo;
time(&now);
localtime_r(&now, &timeinfo);
strftime(time_string, size, "%Y-%m-%d %H:%M:%S", &timeinfo);
}
void print_chip_info() {
esp_chip_info_t chip_info;
uint32_t flash_size;
esp_chip_info(&chip_info);
printf("This is %s chip with %d CPU core(s), %s%s%s%s, ",
CONFIG_IDF_TARGET,
chip_info.cores,
(chip_info.features & CHIP_FEATURE_WIFI_BGN) ? "WiFi/" : "",
(chip_info.features & CHIP_FEATURE_BT) ? "BT" : "",
(chip_info.features & CHIP_FEATURE_BLE) ? "BLE" : "",
(chip_info.features & CHIP_FEATURE_IEEE802154) ? ", 802.15.4 (Zigbee/Thread)" : "");
unsigned major_rev = chip_info.revision / 100;
unsigned minor_rev = chip_info.revision % 100;
printf("silicon revision v%d.%d, ", major_rev, minor_rev);
if(esp_flash_get_size(NULL, &flash_size) != ESP_OK) {
printf("Get flash size failed");
return;
}
printf("%" PRIu32 "MB %s flash\n", flash_size / (uint32_t)(1024 * 1024),
(chip_info.features & CHIP_FEATURE_EMB_FLASH) ? "embedded" : "external");
printf("Minimum free heap size: %" PRIu32 " bytes\n", esp_get_minimum_free_heap_size());
}
// ############### Status indicator ###############
void init_led() {
gpio_reset_pin(BLINK_GPIO);
gpio_set_direction(BLINK_GPIO, GPIO_MODE_OUTPUT);
gpio_set_level(BLINK_GPIO, 1);
}
void led_flicker(int times, bool fast) {
for(u_int8_t i = 0; i < times; i++) {
gpio_set_level(BLINK_GPIO, 0);
vTaskDelay(pdMS_TO_TICKS(fast ? 250 : 500));
gpio_set_level(BLINK_GPIO, 1);
vTaskDelay(pdMS_TO_TICKS(fast ? 250 : 500));
}
}
// ############### Measurement ###############
void read_dht11(float *humidity, float *temperature) {
uint8_t data[5] = {0};
gpio_set_direction(DHT11_GPIO, GPIO_MODE_OUTPUT);
gpio_set_level(DHT11_GPIO, 0);
vTaskDelay(pdMS_TO_TICKS(20));
gpio_set_level(DHT11_GPIO, 1);
gpio_set_direction(DHT11_GPIO, GPIO_MODE_INPUT);
while (gpio_get_level(DHT11_GPIO) == 1) vTaskDelay(pdMS_TO_TICKS(0.1));
while (gpio_get_level(DHT11_GPIO) == 0) vTaskDelay(pdMS_TO_TICKS(0.1));
for (int i = 0; i < 40; i++) {
while (gpio_get_level(DHT11_GPIO) == 1) vTaskDelay(pdMS_TO_TICKS(0.1));
while (gpio_get_level(DHT11_GPIO) == 0) vTaskDelay(pdMS_TO_TICKS(0.1));
uint32_t pulse_start = esp_timer_get_time();
while (gpio_get_level(DHT11_GPIO) == 1) vTaskDelay(pdMS_TO_TICKS(0.1));
uint32_t pulse_end = esp_timer_get_time();
uint8_t bit = (pulse_end - pulse_start) > 50 ? 1 : 0;
data[i / 8] <<= 1;
data[i / 8] |= bit;
}
uint8_t humidity_int = data[0];
uint8_t humidity_dec = data[1];
int8_t temperature_int = (data[2]);
uint8_t temperature_dec = data[3];
uint8_t checksum = data[4];
uint8_t sum = humidity_int + humidity_dec + temperature_int + temperature_dec;
if (sum != checksum) {
#if PRINT_DEBUG
printf("Checksum failed! Retrying...\n");
#endif
vTaskDelay(pdMS_TO_TICKS(1000));
read_dht11(humidity, temperature);
return;
}
*humidity = (float)humidity_int + (float)humidity_dec / 10.0f;
*temperature = (float)temperature_int + (float)temperature_dec / 10.0f;
}
void make_measurement() {
float humidity, temperature;
read_dht11(&humidity, &temperature);
char time_string[64] = {0};
get_current_time(time_string, sizeof(time_string));
#if PRINT_DEBUG
printf("Measurement: [%s, %.1f%%, %.1f°C]\n", time_string, humidity, temperature);
#endif
// Store in RTC buffer
if (rtc_buffer_index < DATA_BUFFER_SIZE) {
strncpy(rtc_measurement_buffer[rtc_buffer_index].timestamp, time_string, sizeof(time_string));
rtc_measurement_buffer[rtc_buffer_index].humidity = humidity;
rtc_measurement_buffer[rtc_buffer_index].temperature = temperature;
rtc_buffer_index++;
}
}
// ############### IO operations ###############
void init_filesystem() {
esp_vfs_spiffs_conf_t conf = {
.base_path = "/spiffs",
.partition_label = "storage",
.max_files = 5,
.format_if_mount_failed = true
};
esp_err_t ret = esp_vfs_spiffs_register(&conf);
if (ret != ESP_OK) {
#if PRINT_DEBUG
printf("Failed to initialize SPIFFS (%s)\n", esp_err_to_name(ret));
#endif
return;
}
#if PRINT_DEBUG
printf("SPIFFS initialized successfully\n");
#endif
}
void save_buffer_to_persistent(){
FILE *f = fopen("/spiffs/measurements.csv", "a");
if (f == NULL) {
printf("Failed to open CSV file!\n");
return;
}
// Write header if file is empty
fseek(f, 0, SEEK_END);
if (ftell(f) == 0) {
fprintf(f, "Timestamp,Humidity,Temperature\n");
}
// Write all buffered measurements
for (int i = 0; i < rtc_buffer_index; i++) {
fprintf(f, "%s,%.1f,%.1f\n",
rtc_measurement_buffer[i].timestamp,
rtc_measurement_buffer[i].humidity,
rtc_measurement_buffer[i].temperature);
}
fclose(f);
rtc_buffer_index = 0; // Reset buffer
#if PRINT_DEBUG
printf("CSV file updated with %d measurements!\n", DATA_BUFFER_SIZE);
#endif
}
void clear_file(){
led_flicker(10, false);
FILE *f = fopen("/spiffs/measurements.csv", "w");
if (f) {
fprintf(f, "Timestamp,Humidity,Temperature\n");
fclose(f);
}
}
void readout_persistent_as_csv(){
FILE *f = fopen("/spiffs/measurements.csv", "r");
if (f) {
char line[256];
while (fgets(line, sizeof(line), f)) {
printf("%s", line);
}
fclose(f);
}
}
// ############### Buffer operations ###############
void readout_buffer_as_csv(){
for (int i = 0; i < rtc_buffer_index; i++) {
printf("%s,%.1f,%.1f\n",
rtc_measurement_buffer[i].timestamp,
rtc_measurement_buffer[i].humidity,
rtc_measurement_buffer[i].temperature);
}
}
// ############### Main thread ###############
const uint16_t sleep_time_seconds = 15 * 60; // Measurement frequency
void app_main() {
setlocale(LC_ALL, "C");
set_system_time();
init_led();
init_filesystem();
led_flicker(3, true);
#if PRINT_DEBUG
printf("DHT11 temperature and humidity sensor\n");
char start_time[64] = {0};
get_current_time(start_time, sizeof(start_time));
printf("Program started at: %s\n", start_time);
print_chip_info();
#endif
make_measurement();
if (rtc_buffer_index >= DATA_BUFFER_SIZE) {
save_buffer_to_persistent();
}
readout_persistent_as_csv();
readout_buffer_as_csv();
#if WIPE_MEMORY
clear_file();
#endif
rtc_unix_time += sleep_time_seconds;
esp_sleep_enable_timer_wakeup(sleep_time_seconds * 1000000);
esp_deep_sleep_start();
}