#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321
#include <SPI.h>
#include <SD.h>
const int chipSelect = 4;
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(115200);
dht.begin();
Serial.print("Initializing SD card...");
// see if the card is present and can be initialized:
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
// don't do anything more:
while (1);
}
Serial.println("card initialized.");
}
void loop() {
float temperature = dht.readTemperature();
float humidity = dht.readHumidity();
// Check if any reads failed and exit early (to try again).
if (isnan(temperature) || isnan(humidity)) {
Serial.println(F("Failed to read from DHT sensor!"));
return;
}
// Wait a few seconds between measurements.
delay(2000);
String dataString = "";
// read three sensors and append to the string:
dataString += "Humidity: ";
dataString += humidity;
dataString += "% Temperature: ";
dataString += temperature;
dataString += "°C ";
// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
File dataFile = SD.open("datalog.txt", FILE_WRITE);
// if the file is available, write to it:
if (dataFile) {
dataFile.println(dataString);
dataFile.close();
// print to the serial port too:
Serial.println(dataString);
}
// if the file isn't open, pop up an error:
else {
Serial.println("error opening datalog.txt");
}
}