前言

具体SD卡接线可以参考 Arduino读写SD卡模块（获得SD卡信息）
本篇博客使用温湿度传感器DHT22来举例，至于其他的传感器大家可以举一反三

硬件准备

SD卡模块
请添加图片描述
温湿度传感器DHT22
在这里插入图片描述

DHT22	Arduino
+	5V
S	7
GND	GND

代码部分

温湿度检测

#include <dht.h>
#define DHTPin 7 
dht DHT; 

void loop() {
    
    
  
  int readData = DHT.read22(DHTPin);
  float t = DHT.temperature; 
  float h = DHT.humidity;

  Serial.print("Temperature = ");
  Serial.print(t);
  Serial.print(" *C "); 
  Serial.print("    Humidity = ");
  Serial.print(h);
  Serial.println(" % ");

创建.txt文件

myFile = SD.open("可以自主命名.txt", FILE_WRITE);

写入SD卡的函数：“myFile”

if (myFile) {
    
      
    myFile.print("Temperature = "); 
    myFile.print(t);
    myFile.print(",");  
    myFile.print("    Humidity = ");  
    myFile.println(h);
    myFile.close(); //结束文件记录
  }

判断文件是否可以打开

else {
    
    
    Serial.println("error opening data.txt");
  }

完整代码

#include <SD.h>
#include <SPI.h>
#include <dht.h>
#define DHTPin 7 
dht DHT; 
File myFile;
int pinCS = 4; 
void setup() {
    
    
   
  Serial.begin(9600);
  pinMode(pinCS, OUTPUT);
  
  // SD Card Initialization
  if (SD.begin())
  {
    
    
    Serial.println("SD card is ready to use.");
  } else
  {
    
    
    Serial.println("SD card initialization failed");
    return;
  }
}
void loop() {
    
    
  
  int readData = DHT.read22(DHTPin);
  float t = DHT.temperature; 
  float h = DHT.humidity;

  Serial.print("Temperature = ");
  Serial.print(t);
  Serial.print(" *C "); 
  Serial.print("    Humidity = ");
  Serial.print(h);
  Serial.println(" % ");

  myFile = SD.open("data.txt", FILE_WRITE);
  if (myFile) {
    
      
    myFile.print("Temperature = "); 
    myFile.print(t);
    myFile.print(",");  
    myFile.print("    Humidity = ");  
    myFile.println(h);
    myFile.close(); // close the file
  }
  else {
    
    
    Serial.println("error opening data.txt");
  }
  delay(500);  
}