Inspiration
Our project focuses on automating soil moisture monitoring and irrigation control to improve plant health and reduce water waste. Since agriculture accounts for 70% of global freshwater withdrawals, we recognize the need for efficient water management to ensure sustainability (ERS, USDA). Overwatering can cause root rot and nutrient leaching, while underwatering can reduce crop yields, with research showing that plants thrive best at 75% water holding capacity (WHC) (PMC). Traditional irrigation methods can be inefficient, wasting up to 60% of water due to evaporation and runoff (MIT News). To tackle this, we designed a system that uses a soil moisture sensor to monitor conditions and a servo-operated water valve to adjust water flow dynamically. This ensures that plants receive the right amount of water, preventing overuse and keeping soil moisture within the optimal range for growth. By automating irrigation, we aim to promote water conservation, healthier crops, and smarter irrigation practices, making our project a valuable solution for both home gardeners and commercial agriculture.
What it does
We fabricated a custom soil moisture sensor by stripping two pieces of copper wire and creating probes for measuring soil moisutre. The sensor works by creating an effective voltage divider, as the resistance between the two probes when placed in the soil decreases when it is moisturized; we read the voltage on one of the analog inputs of the Arduino, and a higher voltage reading corresponds to more moisturized soil due to the lower resistance. The system continuously monitors soil moisture, displaying real-time readings on an OLED screen. In code, we implemented a simple linear mapping between moisture readings and the degree of servo motor opening, so half moisturized soil will result in the cover opening halfway, instead of completely open or closed. The servo adjusts the valve to regulate water flow—ensuring plants receive just the right amount of hydration while minimizing water waste.
Challenges we ran into
The biggest challenge we ran into was calibrating the servo motor position to map the pipe cover to the two "extreme" positions of completely opened and completely closed. It took trial and error, but we eventually got it to work.
Accomplishments that we're proud of
We were successful in successfully creating the soil moisture sensor from scratch, not needing to use any of the avaiable sensors that were available for pickup. This ensured that we understood the electrical engineering principles behind designing the sensor we were using.
What's next for our project.
One of our long term goals for this project is to incorporate more sopthisticated data processing methods, taking into account more variables such as temperature, current water flow, and more advanced mechanical design techniques such as a full fledged valve, etc.
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