Are you intending that the user interface be on the Arduino? Or, are you intending the user interface be run on a PC that talks to the Arduino?
It will be smoother to start with the user interface to be running on a PC that communicates with the Arduino, since we do have the USB port as an advantage on Arduino kits, i will be making use of it . .
I came across some researches with Arduino Scada, will that do for my project, i still do not know the complexity behind building this interface via scada and the codes to be implemented, but i can see this way will be easier. . .
Any other suggestions please will be welcome . . .
I would get a Mega, it may wind up being more than you need and they are more expensive than say a Uno but unless you're a poor student another $30 or so shouldn't matter. If it does matter then get a Uno.
I will be seeing both the specs of the Mega and the Uno, and of course the price to see if it meets my budget,
and will decide it soon.
1. Controlling the ambient temperature of the Greenhouse. Simple LM35 style sensor or maybe a DS18S20 1-wire device.
Can this LM35 signal be controlled as analog ?
I will look into the specs ASAP, my worry for the sensing part will be the voltage supply, Im I to provide an external power supply to the sensing devices or can it get the supply form the Arduino supply ? ?
2. Controlling the humidity level of the soil. Measure resistance between two nails in the soil, there are also sensors that do the same.
Will look into a ready made sensor, else i will be building one i got a circuit for that . . see attached. .
If i will be building the sensor what should i use for the sensor leads . . copper will be best suited, how to fix something, will nail do the job?
3. Controlling the light of the Greenhouse. Transistor or relay, depends on voltage and wattage of light.
For the light i will be going for an LDR, i will need to resolve the supply issue to be able to move forward . .
As far as outputs is concerned, well i will be going through the relays, more appropriate, but as for now, i shall concentrate upon choosing the right inputs first and clear the voltage issue and choose my arduino kit.
Suggestions and comments are always welcomed and will be appreciated . .
Thanks . .
taz . .