ESP32 BUILT-IN THERMOMETER¶

INTRODUCTION¶

Info

The ESP32 chip has a built-in temperature sensor that can be used to measure the temperature of the chip.

USE CASES¶

Measure the internal temperature of the ESP32 chip and display it on the LCD.

INVOLVED RESOURCES¶

ESP32 built-in temperature sensor
0.96-inch LCD
LED (optional)

CODE¶

temp.h¶

/**
 * @file temp.h
 * @author 
 * @brief This file is to drive the built-in temperature sensor of ESP32
 * @version 1.0
 * @date 2024-11-19
 * @ref Alientek Driver
 * @copyright Copyright (c) 2024
 * 
 */

#ifndef __SENSOR_H__
#define __SENSOR_H__

#include "esp_err.h"
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/temperature_sensor.h"

/* Parameter definitions */
#define SENSOR_RANGE_MIN    -10      /* Minimum temperature to be tested */
#define SENSOR_RANGE_MAX    80      /* Maximum temperature to be tested */

/* Function declarations */
void temperature_sensor_init(void); /* Initialize the internal temperature sensor */
short sensor_get_temperature(void); /* Get the temperature value from the internal temperature sensor */

#endif

temp.c¶

/**
 * @file temp.c
 * @author 
 * @brief This file is to drive the built-in temperature sensor of ESP32
 * @version 1.0
 * @date 2024-11-19
 * @ref Alientek Driver
 * @copyright Copyright (c) 2024
 * 
 */

#include "temp.h"

esp_err_t rev_flag;
temperature_sensor_handle_t temp_handle = NULL; /* Temperature sensor handle */

/**
 * @brief       Initialize the internal temperature sensor
 * @param       None
 * @retval      None
 */
void temperature_sensor_init(void)
{
    temperature_sensor_config_t temp_sensor;

    temp_sensor.range_min = SENSOR_RANGE_MIN;   /* Minimum temperature to be tested */
    temp_sensor.range_max = SENSOR_RANGE_MAX;   /* Maximum temperature to be tested */

    rev_flag |= temperature_sensor_install(&temp_sensor, &temp_handle);
    ESP_ERROR_CHECK(rev_flag);
}

/**
 * @brief       Get the temperature value from the internal temperature sensor
 * @param       None
 * @retval      Returns the internal temperature value
 */
short sensor_get_temperature(void)
{
    float temp;

    /* Enable the temperature sensor */
    rev_flag |= temperature_sensor_enable(temp_handle);

    /* Retrieve sensor data */
    rev_flag |= temperature_sensor_get_celsius(temp_handle, &temp);

    /* Disable the temperature sensor after use to save power */
    rev_flag |= temperature_sensor_disable(temp_handle);
    ESP_ERROR_CHECK(rev_flag);

    return temp;
}

Tip

在CMakelists.txt中添加temp.h, temp.c所在路径，分别添加到头文件和源文件对应位置。

main¶

/**
 * @file main.c
 * @author
 * @brief Main application to demonstrate the use of ESP32 internal temperature sensor
 * @version 1.0
 * @date 2024-11-17
 *
 * @copyright Copyright (c) 2024
 *
 */

/* Dependencies */
// Basic
#include "esp_system.h"
#include "esp_chip_info.h"
#include "esp_psram.h"
#include "esp_flash.h"
#include "nvs_flash.h"
#include "esp_log.h"

// RTOS
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

// BSP
#include "led.h"
#include "rgb.h"
#include "key.h"
#include "exit.h"
#include "lcd.h"
#include "spi.h"
#include "esp_rtc.h"
#include "temp.h"

void app_main(void)
{
    int16_t temp;
    esp_err_t ret;

    ret = nvs_flash_init(); /* Initialize NVS */

    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();
    }

    led_init();                /* Initialize LED */
    spi2_init();               /* Initialize SPI2 */
    lcd_init();                /* Initialize LCD */
    temperature_sensor_init(); /* Initialize internal temperature sensor */

    lcd_show_string(0, 0, 200, 16, 16, "TEMPERATURE: 00.00C", BLUE);

    while (1)
    {
        temp = sensor_get_temperature(); /* Get temperature value as float */

        /* Display negative sign if temperature is below zero */
        if (temp < 0)
        {
            temp = -temp;
            lcd_show_string(0 + 10 * 8, 0, 16, 16, 16, "-", BLUE); /* Display '-' sign */
        }
        else
        {
            lcd_show_string(0 + 10 * 8, 0, 16, 16, 16, " ", BLUE); /* No sign for positive values */
        }

        /* Display integer part */
        lcd_show_xnum(0 + 11 * 8, 0, (int)temp, 2, 16, 0, BLUE); /* Convert temp to int for integer part */

        /* Display decimal point */
        lcd_show_string(0 + 13 * 8, 0, 16, 16, 16, ".", BLUE); /* Display decimal point */

        /* Display fractional part */
        lcd_show_xnum(0 + 14 * 8, 0, (int)(temp * 100) % 100, 2, 16, 0, BLUE); /* Multiply by 100 to shift two decimal places */

        led_toggle(); /* Toggle LED to indicate program is running */
        vTaskDelay(250);
    }
}