View source for Online heating system control project

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===[[online heating system control project]]===
====bits and pieces====
=====version 3=====
:[[php www-data program that creates a crontab and calls a C program that executes root commands to copy it into crontabs and install it]]

:write a php file that PUTS some light on on the AVR

:collect data from AVR and store it in mysql
:view the saved data on a client using javascript
====code working on arduino==== 
=====DS18B20 readings to json (in serial monitor)======
::in../electronics/Arduino/[https://github.com/mckennatim/arduino/blob/master/DS18B20Serial_json/DS18B20Serial_json.ino DS18B20Serial_json.ino] 
:key bits:
You need to allocate a buffer for tempstr
 float celsius, fahrenheit;
 String jsn; 
 char tempBuf[32] = {0};
You end the json after you've gone through all the sensors and if you are just starting start a, create a new json string. Otherwise, Increment to next sensor.
  if ( !ds.search(addr)) {//this is where it loops to the next address
	Serial.println("No more addresses.");
	Serial.println();
  	jsn = jsn + "}";//so end the json
  	Serial.println(jsn);//and print it out
  	ctr=0;
    ds.reset_search();//if there are no more devices go back to start of list
    delay(250);
    return;
  } else {
  	if (ctr==0){jsn="{";}//must be just beginning, start the json str
  	++ctr;//since we found a device, increment sensor
  }
The first two bytes of data = ds.read() is the sensor raw temp which gets converted here
  // convert the data to actual temperature

  unsigned int raw = (data[1] << 8) | data[0];
  if (type_s) {
    raw = raw << 3; // 9 bit resolution default
    if (data[7] == 0x10) {
      // count remain gives full 12 bit resolution
      raw = (raw & 0xFFF0) + 12 - data[6];
    }
  } else {
    byte cfg = (data[4] & 0x60);
    if (cfg == 0x00) raw = raw << 3;  // 9 bit resolution, 93.75 ms
    else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms
    else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms
    // default is 12 bit resolution, 750 ms conversion time
  }
  celsius = (float)raw / 16.0;
  fahrenheit = celsius * 1.8 + 32.0;
  dtostrf(fahrenheit, 5, 1, tempBuf); //turns float to string
  jsn= jsn + "\"sensor"+ ctr + "\": " + tempBuf + ", ";//appends temp to json

{{:JSON from arduino to PHP server}}
=====version 4 - temp readings beyond serial monitor=====
:a) separate out a function to provide a reading to send to cosm for pin 0(14) and 1(15)
:1 one possibility - send to cosm. This is better than having a webclient like thermometer.ino. Get it to Cosm and then later set up an api like cosm

=====version 3 - onewire demo=====
Put sample code in function getTemp(). Subsequent calls of the function don't reset the device counter. this is good.

http://sitebuilt.net/images/DS18B20wiring.PNG

On serial monitor running [https://raw.github.com/mckennatim/arduino/master/DS18x20_Temperature/DS18x20_Temperature.ino DS18x20_Temperature.ino] ala [http://www.pjrc.com/teensy/td_libs_OneWire.html the library here]. Of note: How it polls each device:
<syntaxhighlight>
  if ( !ds.search(addr)) {//this is where it loops to the next address
    Serial.println("No more addresses.");
    Serial.println();
    ds.reset_search();//if there are no more devices go back to start of list
    delay(250);
    return;
  }
</syntaxhighlight>

=====version 2=====
:Online thermometer creating web page in which you call for the data by clicking a button. Uses design from [http://www.freetronics.com/pages/online-thermometer#.UOt3dm_2GSo Practical Arduino] in /tim/Documents/electronics/arduino/thermometer[https://raw.github.com/mckennatim/arduino/master/thermometer/thermometer.ino thermometer.ino] and it runs at http://10.0.1.79

=====version 1=====
:Take random readings from analog pins start an etehrnet client that sends them out to http://cosm.com (mcktimo 6j) every ten seconds :[https://raw.github.com/mckennatim/arduino/master/cosmtest/cosmtest.ino comtest.ino]

====final narrative====
An Avr takes in temperature readings from multiple locations. At the control room the AVR hub polls temperature and for each zone knows the set temperature, the default temperature and whether or not a zone is ON and how long it has been on. If it doesn't hear from the (linux) scheduler then it falls back to act as a multi-zone thermostat set at the default temperatures. Through a rudimentary display it would allow you to set temperatures for each zone. 

The scheduler would take temperature data from the AVR client and would know the schedule. Whenever a schedule change point would come up, it would notify the AVR and instruct it to change the set point. It would do this via chrontab maybe.  

The controller would on the client probably an HTML5/javascript client. Here you can read the temperatures and view the schedule. You can override or change the schedule.

====possible routes====
A cheap circuit like http://www.craig.copperleife.com/tech/thermo/ or more complicated http://www.rentron.com/project01.htm using http://datasheets.maximintegrated.com/en/ds/DS1620.pdf which can be overridden by server program that controls multiple thermostats.

====ReST====
:[https://cosm.com/curl?url=v2%2Ffeeds%2F83080 cosm curl helper] 
:http://api.cosm.com/v2/feeds/83080/datastreams/noise.csv?start=2013-01-11T19:30:00Z&end=2013-01-11T21:00:00Z&interval=0 doesn't work
:http://cosm.github.com/cosm-js/tutorial/
:[http://www.lornajane.net/posts/2008/accessing-incoming-put-data-from-php accessing-incoming-put-data-from-php]
:[http://www.gen-x-design.com/archives/create-a-rest-api-with-php/ create-a-rest-api-with-php]
:http://rest.elkstein.org/2008/02/using-rest-in-php.html
:http://blog.garethj.com/2009/02/17/building-a-restful-web-application-with-php/
:[http://api.cosm.com/v2/feeds/83080 get for my feed] 
:[http://www.designspark.com/blog/pachube---making-reliable-connections-with-arduino making-reliable-connections-with-arduino]
=====websockets=====
:http://code.google.com/p/phpwebsocket/
:[http://net.tutsplus.com/tutorials/javascript-ajax/start-using-html5-websockets-today/ start-using-html5-websockets-today]
:[https://github.com/cosm/cosm-js cosm javascript library] [http://cosm.github.com/cosm-js/ docs]

====Cron Jobs====
:[[Hudsonvalley#cron_and_backups]]
:http://net.tutsplus.com/tutorials/php/managing-cron-jobs-with-php-2/
:http://stackoverflow.com/questions/4421020/use-php-to-create-edit-and-delete-crontab-jobs

====parts====
=====[http://www.maximintegrated.com/datasheet/index.mvp/id/2735 DS1620 Digital Thermometer and Thermostat]=====
In a [http://www.rentron.com/project01.htm thermostat circuit] $2.20 for dip
{{:DS18B20 Maxim 1-wire temperature sensors}}