From Antitronics

Networked power monitoring device

This project is a power monitoring device that monitors the current in three conductors and sends the data to a web server for loggin and processing.

The current is monitored using three (model number here) Fluke clamp-on current probes. These probes output 1mA of current for each Amp of monitored current, with a maximum capacity of 400A.

The probe signals are conditioned by a circuit (details here)

The output of the conditioning circuit is connected to three analog input pins on an Arduino Duemilanove board. An Adafruit ethernet shield is connected to the Arduino, with an XPort module installed.

There are two pieces of software used. One is the Arduino sketch, which runs on the monitoring device. The other is a php script which runs on a web server to accept the data over the network from the device, and to log it.

Here is the Arduino sketch used:

// Copyright 2009 by Steve Conklin http://www.antitronics.com
// released to the public domain
//
// derived from some code and ideas by Maurice Ribble:
// http://www.glacialwanderer.com/hobbyrobotics
// http://www.glacialwanderer.com/hobbyrobotics/?cat=5&paged=2

// This sketch sends the values from the first three analog inputs to a web server
// for logging. It uses the adafruit ethernet shield with an XPort module installed.
// The XPORT connections and configuration are *almost* the same as documented on the adafruit
// web site: http://www.ladyada.net/make/eshield/index.html
//
// You must install the AF_XPort and NewSoftSerial libraries - see ladyada's site for links to them
//
// XPort connections on the eshield:
//
// XPort RX pin -> Arduino digital pin 2
// XPort TX pin -> Arduino digital pin 3
// XPort Reset pin -> Arduino digital pin 4
// XPort DTR pin -> Arduino digital pin 5 (not used)
// XPort CTS pin -> Arduino digital pin 6
// XPort RTS pin -> Arduino digital pin 7 (not used)
//
// XPort configuration:
//
// *** Channel 1
// Baudrate 57600, I/F Mode 4C, Flow 02
// Port 10001
// Connect Mode : D4
// Send '+++' in Modem Mode enabled
// Show IP addr after 'RING' enabled
// Auto increment source port disabled
// Remote IP Adr: --- none ---, Port 00000
// Disconn Mode : 80  Disconn Time: 00:03 <=== Different than adafruit example, she uses Disconn Mode = 0
// Flush   Mode : 77

// These are web server specific values
#define PHP_PAGE_LOCATION "/monitor/power.php"
#define WEB_HOST "HOST: mydomainname.com\n\n"
#define CONN_IP "172.130.0.003"
#define CONN_PORT 80

#include "AF_XPort.h"
#include "NewSoftSerial.h"

// the xport!
#define XPORT_RX        2
#define XPORT_TX        3
#define XPORT_RESET     4
#define XPORT_CTS       6
#define XPORT_RTS       0 // not used
#define XPORT_DTR       0 // not used
AF_XPort xport = AF_XPort(XPORT_RX, XPORT_TX, XPORT_RESET, XPORT_DTR, XPORT_RTS, XPORT_CTS);

char linebuffer[128];
int retstat;

void printstatus(int)
{
  // no output for success
  if (retstat == ERROR_TIMEDOUT)
    Serial.println("ERROR: Timeout");
  else if (retstat == ERROR_BADRESP)
    Serial.println("ERROR: Bad Response");
  else if (retstat == ERROR_DISCONN)
    Serial.println("ERROR: Disconnect");

  return;
}

void setup()
{
  Serial.begin(57600);
  Serial.println("serial port ready");
  xport.begin(57600);
  retstat = xport.reset();
  printstatus(retstat);
  Serial.println("XPort ready");
}

void loop()
{
  int value0, value1, value2;
  uint8_t read;
  char cbuffer[128];

  //Serial.println("Connecting");
  retstat = xport.connect(CONN_IP, CONN_PORT);
  printstatus(retstat);
  //Serial.println("Sending GET");

  //Serial.println("Request");
  value0 = analogRead(0);
  value1 = analogRead(1);
  value2 = analogRead(2);

  sprintf(cbuffer, "GET %s?value0=%d&value1=%d&value2=%d HTTP/1.1\n%s", PHP_PAGE_LOCATION,value0,value1,value2,WEB_HOST);
  Serial.println(cbuffer);
  xport.print(cbuffer);

  // read back the status from the web host
  read = xport.readline_timeout(linebuffer, 128, 1000);
  //Serial.println(read, DEC);   // debugging output
  //Serial.print(linebuffer); // debugging output

  //Serial.println("sent - sleeping");
  // Delay for 1 minute
  delay(60000);
  // The disconnect notification 'D' character probably arrived during this interval
  // so flush it so we don't read it after our next connect attempt
  xport.flush(255);
}

Here is the php script from the server:

<?php
// Setup variables
$value0 = $_GET['value0'];
$value1 = $_GET['value1'];
$value2 = $_GET['value2'];

// This code by Maurice Ribble:
// http://www.glacialwanderer.com/hobbyrobotics
// http://www.glacialwanderer.com/hobbyrobotics/?cat=5&paged=2

// if you are testing or your value is never actually zero, turn this on
//if (!$value0 || !$value1 || !value2)
//{
//  echo "<html><body>
//
//You need to pass in valid _GET parameters.  Script Terminated.</body></html>";
//  exit;
//}

$fp = fopen("/path/to/websiteroot/monitor/powerlog.txt", 'at');
if (!$fp)
{
	echo '<html><body>

Failed to open file</body></html>';
	exit;
}

$tstamp = date("m/d/Y G:i:s");

$outputstring = "$tstamp $value0 $value1 $value2\r\n";
fwrite($fp, $outputstring, strlen($outputstring));
// end with a 0 to close the session to the client:
echo "\0";
end;
?>