Since my second milestone I have improved my project by integrating Raspberry Pi into my project. The Raspberry Pi is connected to the arduino through serial communications, where the arduino sends the sensor data over. The Raspberry Pi hosts a server that has a website inside, and the website shows a graph of the data from the sensors so you can monitor it as long as you are connected to the same wifi.

I have recently just finished my second milestone, which was to improve and build a physical body for the project. This setup has two circuits, one for the water pump, and one for the arduino and is sensors on the perfboard. The arduino circuit contains the arduino microcontroller, a homemade water level sensor, a soil moisture sensor, and a temperature + humidity combo sensor. The water level sensor consists of two galvanized nails in a wood holder (block of wood with slots in it for the nails). When the water level sensor nails are not touching a common object or liquid, the output will be 1023 because the circuit is not closed, and when they are touching a common object or liquid a legitimate output will result which can vary depending on the substance and its conductivity. The soil moisture sensor also uses the same concept as the water level sensor but is optimized for use in soil. The DHT11 humidity sensor part works using a moisture holding substance sandwiched in between two electrodes. As humidity rises the moisture holding substance absorbs water thus altering the conductivity of it which is measured and used to calculate the humidity. The temperature part of the DHT11 uses a thermistor (thermal variable resistor) that decreases resistance as temperature increases, which is then calculated for an output. The relay circuit consists of a relay, water pump and battery. The relay acts as a switch controlled by the arduino circuit. The data from the sensors is inputted into the Arduino, which runs its code. Depending on the values inputted, the arduino will decide to either run the water pump, or to leave the plant as is. As well as deciding whether the pump should be watered, it also displays the data on a front-mounted LCD.