Hi, I am interested in sending lots of sensory data (perhaps about 15-25, mostly analog but some digital, from the same room, wirelessly) to Arduino Mega. Is this possible? What is the maximum number of sensor channels? Besides the sensors, what hardware do I need?
It depends very much on the sensors and how they need to be connected.
I2C, for example, is a bus using 2 Arduino pins and you can hang loads of sensors on the same bus (subject to their addresses being unique). That gives you lots of sensors at a cost of only 2 pins total (plus power).
On the other hand sensors like PIR would have one digital line out each at a cost of one Arduino digital pin each.
So you really need to determine what sensors you think you might be using, then ask the question again....
Sorry I meant sending the sensory values to Arduino wirelessly. I am interested in monitoring the plants in a green house.
That will also depend on what kind of sensor you are using.
Are the sensors already wireless with their own logic? If not, you need to connect them physically to something that can read the values ( for example another arduino) and send it wirelessly to your Mega.