Notes :

• for this setup the connections are made on the ethernet shield instead of directly on the arduino. Since Fritzing misses a library with external shield I used the arduino, the pinout stays the same either way.
• check the DS18B20 datasheet for the specifications on hooking up the sensor in parasite or powered mode

Schematics :

The arduino reads the sensors every 10 seconds and passes the data to a php script on your website; which then stores the data in a text file. A second script generates a line chart of the collected data.

22 hours of temperature data

I started from Cyberspice’s code and changed the arduino code to make use of the DB18S20 and the ethernet shield.

A variable was added to the upload php script in order to store the light intensity in addition to the temperature.

The graphing script was altered to also display the minimum temperature, the maximum temperature, the current temperature and the average temperature. A raster was added for a better interpretation of the plotted data and a green line is showing the average temperature  troughout the chart.

You need to alter your ip, domain and path as I explained in the post Arduino Wireless motion detector so I won’t go into those details here.

The arduino sketch :

#include <OneWire.h>
#include <string.h>
#include <Ethernet.h>

int count = 0;
OneWire ds(8);
int HighByte, LowByte, TReading, SignBit, Tc_100, Tf_100, Whole, Fract;
int Tcount = 1;
int W[6];
int F[6];
int photocellPin = 0;     // the cell and 10K pulldown are connected to a0
int light;     // the analog reading from the sensor divider

byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = {
  192, 168, 1, 36};
byte server[] = { 77, 222, 78, 32};
// String buffer
char buffer[256];

Client client(server, 80);

void setup()
{
  Ethernet.begin(mac, ip);
  Serial.begin(9600);

  delay(1000);

  // Serial.println("connecting...");

}

void loop()
{
  byte i;
  byte present = 0;
  byte data[12];
  byte addr[8];

  if ( !ds.search(addr)) {
    ds.reset_search();
    return;
  }

  ds.reset();
  ds.select(addr);
  ds.write(0x44,1);         // start conversion, with parasite power on at the end

  delay(1000);            

  present = ds.reset();
  ds.select(addr);
  ds.write(0xBE);         // Read Scratchpad

  light = analogRead(photocellPin);
  Serial.print("light intensity = ");
  Serial.print(light);
  Serial.print("\n");
  for ( i = 0; i < 9; i++) {           // we need 9 bytes
    data[i] = ds.read();
  }

  LowByte = data[0];
  HighByte = data[1];
  TReading = (HighByte << 8) + LowByte;
  SignBit = TReading & 0x8000;  // test most sig bit
  if (SignBit) // negative
  {
    TReading = (TReading ^ 0xffff) + 1; // 2's comp
  }
  Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25

  Whole = Tc_100 / 100;  // separate off the whole and fractional portions
  Fract = Tc_100 % 100;

  if (SignBit) // If its negative
  {
    Serial.print("-");
  }
  Serial.print(Whole);
  Serial.print(".");
  if (Fract < 10)
  {
    Serial.print("0");
  }
  Serial.print(Fract);
  Serial.print(" C\n");

  if (client.connect()) {
    Serial.println("connected");
 sprintf(buffer, "HEAD /path/to/script/newtemp.php?count=%d&temp=%d.%d&light=%d HTTP/1.1", Tcount, Whole, Fract, photocell);
 client.println(buffer);
 client.println("Host: yourdomain.com");
 client.println("Connection: close");
 client.println();
 client.stop();
 Tcount++;
 }
 else {
 Serial.println("connection failed");
 }
 delay(60000);  // wait 1 minute before sending new data
}

The upload script  ‘newtemp.php’ :

<?php

if ($_SERVER['REQUEST_METHOD'] == 'HEAD') {

	$fields = explode("&", $_SERVER['QUERY_STRING']);
	$values = array();

	foreach ($fields as $field) {
		$keyval = explode("=", $field);
		$values[$keyval[0]] = $keyval[1];
	}

	$file = fopen('./tempdata.txt','a+');
	if ($file) {
		fwrite($file, time() . ':' . $values['count'] . ':' . $values['temp'] . ':' . $values['light']);
		fwrite($file, "\n");
		fclose($file);
	}
}

?>

The graphing script ‘tempgraph.php’ :

<?php

define('WIDTH', 1000);
define('HEIGHT', 520);
define('FONT', 1);
 define('FONT2',2);

// Get the temperature data
$data = array();
$file = fopen("./tempdata.txt","r");
if ($file) {
	while (!feof($file)) {
		$line = trim(fgets($file));
		if (strlen($line)) {
			$fields = explode(":", $line);
			$keyval = array();
			$keyval['time']        = $fields[0];
			$keyval['count']       = $fields[1];
			$keyval['temperature'] = $fields[2];
			$keyval['light'] 	   = $fields[3];
			$data[] = $keyval;
		}
	}

	fclose($file);
}

// Get the number of data points
$datapoints = count($data);

// Lines are chronological
$mintime = $data[0]['time'];
$maxtime = $data[$datapoints - 1]['time'];

// Temperatures need to be processed.
$mintemp = $data[0]['temperature'];
$maxtemp = $data[0]['temperature'];

foreach ($data as $datapoint) {
	$mintemp = $mintemp < $datapoint['temperature'] ?
	           $mintemp : $datapoint['temperature'];
	$maxtemp = $maxtemp > $datapoint['temperature'] ?
	           $maxtemp : $datapoint['temperature'];
	$avgtemp += $datapoint['temperature'];
	$curtemp = $datapoint['temperature'];
}
 $avgtemp = round(($avgtemp / $datapoints),2);

// Get the axis dimensions.  Round up and down to the nearest
// degree C and hour.
$lowtime  = intval($mintime / 3600) * 3600;
$hightime = (intval($maxtime / 3600) + 1) * 3600;
$difftime = $hightime - $lowtime;

$lowtemp  = intval($mintemp);
$hightemp = intval($maxtemp) + 1;
$difftemp = $hightemp - $lowtemp;

// Create the image
$image = imagecreate(WIDTH, HEIGHT);
if ($image) {
	$background = imagecolorallocate($image, 255, 255, 255);
	$black      = imagecolorallocate($image, 0, 0, 0);
	$red        = imagecolorallocate($image, 255, 0, 0);
	$blue       = imagecolorallocate($image, 0, 0, 255);
	$green		= imagecolorallocate($image, 0, 204, 5);
	$grey		= imagecolorallocate($image, 210,210,210);

	// Draw the axes
	imageline($image, 20, 20, 20, 485, $black);
	imageline($image, 15, 480, 980, 480, $black);
	imageline($image, 15, 20, 20, 20, $black);
	imageline($image, 980, 480, 980, 485, $black);

	// Draw top horizontal line
	imageline($image, 20, 20, 980, 20, $grey);

	// Draw right most vertical line
	imageline($image, 980, 20, 980, 479, $grey);

	for ($i = 3600; $i < $difftime; $i += 3600) {
		$x = 20 + (($i * 960) / $difftime);
		// Draw ticks on horizontal axis
		imageline($image, $x, 480, $x, 483, $black);
		// Draw horizontal guides
		imageline($image, $x, 479, $x, 20, $grey);
	}
	$temp = intval($lowtemp);
	for ($i = 1; $i < $difftemp; $i++) {
	    $y = 480 - (($i * 460) / $difftemp);
		// Draw ticks on vertical axis
		imageline($image, 17, $y, 20, $y, $black);

		// Draw vertical guides
		imageline($image, 21, $y, 980, $y, $grey);
		$temp = intval($temp) + 1;
		$ytemp = intval($y) - 5;
		//if($temp % 2 == 0){
			imagestring($image, FONT, 0, $ytemp, $temp . 'C', $black);
		//}
	}

	// Draw the labels
	imagestring($image, FONT, 8, 490, date("H:i", $lowtime), $black);
	imagestring($image, FONT, 970, 490, date("H:i", $hightime), $black);
	imagestring($image, FONT, 0, 475, $lowtemp . 'C', $black);
	imagestring($image, FONT, 0, 15, $hightemp . 'C', $black);

	// Draw min, max and avg
	imagestring($image, FONT2, 700, 430, "Cur. temp : " . $curtemp . " °C",$black);
	imagestring($image, FONT2, 700, 450, "Avg. temp : " . $avgtemp . " °C",$green);
	imagestring($image, FONT2, 850, 430, "Min. temp : " . $mintemp . " °C",$blue);
	imagestring($image, FONT2, 850, 450, "Max. temp : " . $maxtemp . " °C",$red);

	// Draw avg line

	$avgtemp = 480 - ((($avgtemp - $lowtemp) * 460) / $difftemp);
	imageline($image,20, $avgtemp, 980, $avgtemp, $green);

	// Draw the temperature points

	// Position of the first point
	$prevx = (($data[0]['time'] - $lowtime) * 960) / $difftime;
	$prevy = (($data[0]['temperature'] - $lowtemp) * 460) / $difftemp;

	// Draw line from previous point to current point
	for ($i = 1; $i < $datapoints; $i++) {
		$x = (($data[$i]['time'] - $lowtime) * 960) / $difftime;
		$y = (($data[$i]['temperature'] - $lowtemp) * 460) / $difftemp;
		imageline($image, $prevx + 20, 480 - $prevy, $x + 20, 480 - $y, $red);
		$prevx = $x;
		$prevy = $y;
	}

	// Finally time and date stamp
	$generated = 'Generated: ' . date("r");
	imagestring($image,
	            FONT,
	            WIDTH - 15 - (imagefontwidth(FONT) * strlen($generated)),
	            HEIGHT - 15,
	            $generated,
	            $blue);

	// Output the image
	header('Content-Type: image/png');
	imagepng($image);

	// Destroy it
	imagedestroy($image);
}

?>

I will soon post some improvements on the scripts :

• averaging 6 readings ( 1 minute ) to 1 datapoint to get rid of the noise
• let the script fill one text file for each day, so you can look at a history over several days
• split up data into different charts
• last but not least, trying to add the S65 in the game : showing the current sensor readings or a graph

Please leave a comment or send me a link to show your arduino projects!

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Each time motion is detected, the networked arduino connects to the web and executes a php script which writes the time and date of the event to a text file. When you want to check if motion was detected, acces a different php script which displays all (if any) recorded events.

Check my next post to see how to send sensor data from the arduino to a website using php.

If you followed part 1 and part 2 all you need to do for part 3 is change the code of the receiving arduino since we’re only changing the output from ‘blink a led’ to ‘access a website’.

Sketch :

#include <Ethernet.h>

int ledPin = 13;    // pin for the LED
int RFinPin = 8;    // pin for the RF receiver
int val = 0;         // variable for reading the pin status
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };    // unique mac address
byte ip[] = { 192, 168, 1, 36};        // unique and valid ip for your network
byte server[] = { 77, 222, 78, 32};  // ip google

void setup() {
   Ethernet.begin(mac, ip);
   pinMode(ledPin, OUTPUT);    // declare LED as output
   pinMode(RFinPin, INPUT);    // declare RF receiver as input
   Serial.begin(9600);
   delay(1000);
}

Client client(server, 80);

void loop(){
   val = digitalRead(RFinPin);        // read input value
   if (val == HIGH) {
     digitalWrite(ledPin, HIGH);      // turn LED ON
     if (client.connect()) {
       Serial.println("connected");
       client.println( "GET /folder/movement.php HTTP/1.1");
       client.println("Host: yourdomain.com");
       client.println("Connection: close");
       client.println();
       client.stop();
     } else {
       Serial.println("connection failed");
     }
   } else {
     digitalWrite(ledPin, LOW);       // turn LED OFF
   }
   delay(5000);
}

The script movement.php is executed when the arduino connects to www.yourdomain.com/folder/movement.php

movement.php code :

<?php

$myFile = "movement_data.txt";
$fh = fopen($myFile, 'a') or die("can't open file");
$stringData = date("D, d M Y H:i:s") . "\n";
fwrite($fh, $stringData);

fclose($fh);

?>

The script display_movement.php takes the movement data and prints one line for every event recorded.

display_movement.php code:

<?php

 $fileName = "movement_data.txt";

 if(file_exists($fileName)){
      $file = fopen($fileName,'r');

      while(!feof($file)){
                $name = fgets($file);
                if($name != NULL){
                echo('<br>'. "Movement registered on : ".$name.'</br>');
			}
        }

        fclose($file);
}
?>

When display_movement.php is executed you should see something like :

In the next post I’ll discuss how to write sensor data (light intensity, temperature,…) to a website and plot a line chart using php.

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