ESP32 DS18B20 Dallas Temperature Sensor

#include <stdio.h>
#include <string.h>
#include "esp_log.h"
#include "esp_err.h"
#include "ds18b20.h"
#include "onewire_bus.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#define ONE_WIRE_GPIO    4   // Change this to your preferred GPIO pin
#define MAX_DS18B20      2   // Maximum number of DS18B20 sensors
#define DS18B20_CONVERSION_DELAY_MS 750  // Default conversion delay for 12-bit resolution

static const char *TAG = "DS18B20";

void app_main(void) {
    // Install the 1-Wire bus
    onewire_bus_handle_t bus = NULL;
    onewire_bus_config_t bus_config = {
        .bus_gpio_num = ONE_WIRE_GPIO,
    };

    onewire_bus_rmt_config_t rmt_config = {
        .max_rx_bytes = 10, // 1-byte ROM command + 8 bytes ROM number + 1 byte device command
    };

    ESP_ERROR_CHECK(onewire_new_bus_rmt(&bus_config, &rmt_config, &bus));

    int ds18b20_device_num = 0;
    ds18b20_device_handle_t ds18b20s[MAX_DS18B20];
    onewire_device_iter_handle_t iter = NULL;
    onewire_device_t next_onewire_device;
    esp_err_t search_result = ESP_OK;

    // Create 1-Wire device iterator to search for sensors
    ESP_ERROR_CHECK(onewire_new_device_iter(bus, &iter));
    ESP_LOGI(TAG, "Device iterator created, start searching...");

    do {
        search_result = onewire_device_iter_get_next(iter, &next_onewire_device);
        if (search_result == ESP_OK) {
            ds18b20_config_t ds_cfg = {};  // Initialize DS18B20 config

            // Check if the device is a DS18B20 sensor
            if (ds18b20_new_device(&next_onewire_device, &ds_cfg, &ds18b20s[ds18b20_device_num]) == ESP_OK) {
                ESP_LOGI(TAG, "Found DS18B20[%d], address: %016llX", ds18b20_device_num, next_onewire_device.address);
                ds18b20_device_num++;
            } else {
                ESP_LOGW(TAG, "Found unknown device, address: %016llX", next_onewire_device.address);
            }
        }
    } while (search_result != ESP_ERR_NOT_FOUND);

    ESP_ERROR_CHECK(onewire_del_device_iter(iter));
    ESP_LOGI(TAG, "Searching done, %d DS18B20 device(s) found", ds18b20_device_num);

    // Read and print temperature from each detected DS18B20 sensor
    while (1) {
        for (int i = 0; i < ds18b20_device_num; i++) {
            float temperature = 0.0;
            if (ds18b20_trigger_temperature_conversion(ds18b20s[i]) == ESP_OK) {
                vTaskDelay(pdMS_TO_TICKS(DS18B20_CONVERSION_DELAY_MS));  // Wait for conversion
                if (ds18b20_get_temperature(ds18b20s[i], &temperature) == ESP_OK) {
                    ESP_LOGI(TAG, "DS18B20[%d] Temperature: %.2f°C", i, temperature);
                } else {
                    ESP_LOGE(TAG, "Failed to get temperature from DS18B20[%d]", i);
                }
            } else {
                ESP_LOGE(TAG, "Failed to trigger temperature conversion for DS18B20[%d]", i);
            }
        }
        vTaskDelay(pdMS_TO_TICKS(2000));  // Wait 2 seconds before the next reading
    }
}