Here is the introductory report of our project.
Short description of the concept
SmartPot is an intelligent watering system for flower pots. It uses a soil humidity sensor to calculate if the flower needs more water. Then it has a water reservoir and a pump to water the plant when needed automatically.
Description of how you arrived at your design
The first idea was creating a moving flower pot, with light photodiodes all around the base to get which side was the brightest and then make the pot move toward the light. It was a cool idea, but not for the plant, since it would have been disoriented. That's because plants tend to grow in the direction of light so if the pot moves, the plant would never know where to grow.
So we decided to create something to solve another problem: watering of plants. People may find it really hard to remember watering their plants on time or they may leave their house for a long time so that they can't keep the plants alive. It will be helpful to have a tool to help them watering their plants, totally automated.
Here are the first sketches:
We have a reservoir with water which the user can hang on the ceiling or we could design a proper stand for it. Then we would use a siphon to let the water flow into the pot. We will design our valve in this way: a steel ball would stop the flow of water down the pot and when we want to open it we will use a coil to lift it up and let the water flow down.
As for the sensor, the idea is creating two conductive line close together and measure voltage, that changes when the humidity of soil changes, this is due to the different dielectric properties of soil when dry or not.