I have never done any sort of programming before so I need you to be gentle with me!!
I have been given the task of instructing a bunch of year 9 science club kids in building a desk top greenhouse to grow plants in optimal conditions. It needs to very simply control temperature, to be able to water plants and possibly to open vents to increase air flow as well.
We intend on building perspex boxes to act as the greenhouse...but then I got stuck as to what to do!
We intend on using Arduino to control this, but other than that we will only have basic bulbs and electrical circuit equipment as we are on a very tight budget. What sort of sensors do we need, and how do I connect these up so that they can be controlled by the students' programme?
Very basic help would be much appreciated as I have no idea where to start!!
To measure temperature, the DS18B20 is a favourite - you'll find many many references to it in the forum. You can get a waterproofed version of it too.
Google for garduino - this kind of project has been done many times and there are quite a few well documented versions around the web.
Sensing soil moisture is commonly done with a couple of nails as probes - see garduino above.
Watering may be a problem - you'll need some kind of pump or electrically controlled valve if you have gravity feed. If you're really strapped for budget, you may need to be creative about where you source these.
Linear actuators would be nice for opening vents; sadly they make the cost of all your other parts look like pocket change. Stepper motors or hobby motors and limit switches may have to substitute.
Are you building a single greenhouse or one per student?
We were planning on making one greenhouse per four students or so, and the simpler the better I feel!
I've read through the garduino stuff but to be honest I'm so overwhelmed with all the language used in it and the circuitry that I gave up a little! Would it be an idea if we could just monitor soil moisture and ambient temperature and then use a very basic feedback system (e.g. a simple switch system to complete a circuit to turn a heater on for a specific period of time)?
We only have simple circuitry available and I'm not really sure where to start...sorry to be such a pain but I have been completely lumped with this and I don't understand it at all!