DIY Data Logging Weather Station Under $15

In this instructable I am going to show you how to build a weather station that logs the information that it collects on a sd card.

Step 1: If You Prefer a Video Here It Is

Step 2: Get All the Parts

You need,

1 Arduino board, I used the pro mini

1 dht sensor I used the dht 22

1 10k resistor

1 SD card or micro SD card with matching board

3 feet on wire

3 wire cable (you will use this to connect your dht sensor to the arduino)

if you are using a pro mini you need the stuff to program it, I have a video on how to program one with out a usb to serial adapter you can find it here or you can check out my Instructable on it

Stuff to solder

Step 3: Wire It Up.

connect all the wires as shown in the diagram.

dht sensor Pro mini, Uno & mega.Connect pin 1 (on the left) of the sensor to +5V

NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1 to 3.3V instead of 5V

Connect pin 2 of the sensor to whatever your DHT PIN is

Connect pin 4 (on the right) of the sensor to GROUND

Connect a 10k resistor from vcc to data pin

For the mega MISO-50 MOSI-51 SCK-52 SS/CS 53

For the uno & pro mini MISO-50 MOSI-51 SCK-52 SS/CS-53.

Step 4: Program the Arduino.

// Created by A Homeschoolers Workbench
// 12/1/2016
#include "DHT.h"
#include <sd.h>
File myFile;
int pinCS = 10; // Pin 53 on Arduino mega   10 on pro mini and uno, this is the SS pin
// For the uno and pro mini connect sck-13 miso-12 mosi-11 cs/ss-10
// For mega connect sck-52 miso-50 mosi-51 cs/ss-53
#define DHTPIN 2     // what digital pin we're connected to
// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321  I am using the 22
//#define DHTTYPE DHT21   // DHT 21 (AM2301) 
// Connect pin 1 (on the left) of the sensor to +5V
// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
// to 3.3V instead of 5V!
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10k resistor from vcc to data pin
// Initialize DHT sensor.
DHT dht(DHTPIN, DHTTYPE);
void setup() {
  Serial.begin(9600);     // Start the serial
  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;
}
  dht.begin();
}
void loop() {
  // Wait a 60 seconds between measurements.
  delay(2000);
  // Reading temperature or humidity takes about 250 milliseconds!
  float h = dht.readHumidity();
    // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);
  
//   Check if any reads failed and exit early (to try again).
  if (isnan(h)||isnan(f)) {
    return;
  }
    // Create/Open file 
  myFile = SD.open("TH.txt", FILE_WRITE);
//   if the file opened okay, write to it
if (myFile) {
    Serial.println("Writing to file...");
    // Write to file
  myFile.print(h);    // print Humidity
  myFile.print(",");  // place a divider
  myFile.println(f);  // print the temp and start a new line
    myFile.close(); // close the file
    Serial.println("Done.");
 }               //if the file didn't open, print an error:
else {
    Serial.println("error opening TH.txt");
 }
}