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Topic: Farm ventilation control (Read 4744 times) previous topic - next topic

futureless

Jul 08, 2013, 12:28 am Last Edit: Jul 14, 2013, 06:47 pm by futureless Reason: 1
Hi,

I was making simple ventilation control for my farm.

PHOTOS and SCHEMATIC are here:
http://ge.tt/3pQxzFl

Main functions of system:
* Display current temperature & relative humidity
* Intelligently control 4 fans depending on average temperature of current period
* Ability to set target temperature via buttons

* Relays just open/close 3-phase contactors for each fan. There are buttons for manual contactor ON/OFF + button to break the Arduino relay circuit from contactor box.

Components:

  • Arduino UNO Rev3

  • DHT21 sensor

  • 4 optoisolated relay array

  • LCD keypad shield 16x2



Features:
* Current temperature is being smoothened using moving average
* Fans are being turned on/off every 60 secs
* On sensor failure - fans are turned off & arduino freezes throwing out an error
* There is a 2 sec delay between starting each fan (so to not overload line - each fan ~0.55kW)
* Target temperature is being saved to EEPROM

Arduino source code:
https://gist.github.com/blacktea/5945177

P.S. This is my first project with Arduino and with low-voltage electronics. I will be very glad to receive comments and criticism.

wildbill

Assuming it works, it looks fine. There are a few minor oddities, such as your boolean functions that unconditionally return true.

Personally, I'd leave the debugging serial prints in, without checking whether the debug flag is set - the arduino doesn't care if there's no-one listening. I'd also put an L suffix on the large constants just to make sure the compiler treats them correctly. I don't see the need for an array of temperatures, you can just keep a running average. However, these are very small nitpicky things; overall, it looks clean and clear.


futureless

Thank You for Your remarks.

Edited code, added photos.

robtillaart


I would add an fire-alarm function if the temperature comes above some (serious) threshold.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

futureless

Thanks fire alarm would be fine, yet currently I have no GSM module and not much pins left on UNO.

I'm planning on more advanced farm control system.

Including SMS alerts, web console, ammonia sensor, feeder/water failure sensing and so on...

futureless


robtillaart

Quote
and not much pins left on UNO.

go for an I2C LCD that uses only 2 pins.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

futureless

Thanks for great idea. There are cheap adapters for I2C -> 1602 LCD.

I thought I will need a MEGA...

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