Arduino - controlling fans and door/hatch greenhouse

Dear: Frode

I am really liking your idea but I have one problem with your post. You said that...

 

I want something that can do this :

 

• Open a small door/hatch temp controlled
• Start two fans 12v temp controlled
• Watering system (thats for last)
• Turn on and off heat and lights (for now this is 220v)

But how are you going to do that all. Could you explain your designs if you have any?

From: Noah

Frode,

          yes you can do all you want to do for your greenhouse and in fact I do all of those things in my greenhouse.  However I feel obliged to issue the usual advice regarding the 220 volt stuff, which is unless you are completely competent to work safely with such voltages you should not attempt projects involving mains electricity especially where there is likely to be water / moisture.

At a safer level say 12 volt then you can definitely control low voltage lights, vent openers, fans and a watering system.

For vents you need some form of motorized mechanism to move the vent, the mechanism depends on how much you need the vent to open and its weight. Alternatively a bank of low voltage fans can provide air movement.

For my watering system I use 12 volt solenoid valves, one per plant.  Not cheap initially but very versatile.  Alternatively one valve can control several 'drippers'.

I do use soil heating cables on my propagating benches.  These come prewired and in my case the supply cable goes into a sealed box which houses the control relay in a separate dry area.  The opto isolated control relay is controlled by an Arduino which senses temperature, humidity and ambient light level.  The DHT22 does both temperature and humidity, the BH1750 is the ambient light sensor.  The Dallas 18B20 is also an excellent temperature sensor.

Stealing a phrase from another contributor 'Google is your friend' and my advice to you is to google each of the items you want to do and develop each aspect on its own then add it to your complete system.  All of the sensors I have mentioned have some good information on the net and often Arduino example code and libraries.

It should be the same as what you did with the pi.  you basically use relays.  we would need to know the amps to help you pick the relays.

Hi

I can skip the 220v project for now, most important for me is controlling the fans and the small door. Motor for the door is a drill motor 18v and the fans are radiator fans from a car (yeah low budget style) so they got motor to run it.

Amps on the fans are somewhere between 10 and 15 amps, not sure, but 15 amps fuse working

Frode

A simple Logic level power MOSFET should do the trick there ?

Regards

Peter

I would think that the MOSFET idea proposed by Peter would be the easiest and most efficient way to do what your looking for without the 220v.

Hi

I can see that I need to read alot about this How about this package on ebay

http://www.ebay.com/itm/Sintron-Mega-2560-Starter-Kit-LCD-Servo-Motor-Sensor-for-Arduino-AVR-Learner/271353386561?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D24901%26meid%3Da8c8ba4001944d489e74f01b416bc593%26pid%3D100033%26prg%3D10502%26rk%3D4%26rkt%3D4%26sd%3D311084836752

Any good?

it looks to be as good as any you may find and the price looks good, there is nothing there you should have an issue with and you can always add to it after the fact to suit your needs

Hi

Thanks again for great support and help. These MOSFET on ebay link below, is it just på plug it onto the arduino and of course code/program it? Excuse my english from time to time, my main language is norwegian

Frode

http://www.ebay.com/sch/i.html?_odkw=arduino+mosfet&_from=R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xarduino+Logic+level+power+MOSFET&_nkw=arduino+Logic+level+power+MOSFET&_sacat=0

Yes these would work just fine for up to 24V and a reasonable current (4A ish)

http://www.vishay.com/docs/91017/91017.pdf

I would not exceed about 4A as the FET does not have a heat sink, also if you find it is not turning on fully then you can remove the LED on the card to reduce the controller load

Regards

Peter