Process
Outline your approach to the project? What ideas did you generate and how did you refine or reject them? What did you research and explore? what were the design choices? What challenges were encountered and how did you resolve them?
In this project I wanted the device to do 3 things: 1) Collect data on soil moisture level. 2) Use that data to automate watering. 3) Notify user when the device need to be refilled with water.
For measuring soil moisture level I used a Sparkfun Soil Moisture Sensor that was available in the lab. The quality of the sensor seems to vary part to part. Some provide good data while some other ones didn’t. Otherwise the sensor is easy to use and well documented.
For watering a water pump was needed. I found an unmarked water pump with no documentation besides knowing it’s designed to run on 12v. After some trial and error I found it will start to run around 8v. Since the particle cannot provide that power, power to the pump is proved by a 9v battery and controlled via a NPN Transistor.
The last part was to measure water level. Originally I wanted to use a pressure sensor to measure the water by weight. However, the pressure sensor I had available to me could not produce data that could be used since it laced the fidelity to measure the smaller increments. I switched to my back up plane which used two wire in a similar mater to the soil moisture sensor.