The Plantinator
GEEN 1400 Final Project
2021
The goal of this project is to design and create a device that autonomously monitors and sends alerts to an owner related to moisture and light levels (i.e. the plant talks to you). The target audience for this project is the busy student or working individual lacking time throughout their day. As an overview, a photoresistor and moisture sensor are used to collect data to send to an Arduino Nano microcontroller. The microcontroller interprets these resistances and assigns them a value based on testing parameters for light and moisture levels. Finally, RGB LEDs display a color corresponding to the assigned values. For example, if the moisture LED indicates green, the water content of the soil is ideal.
This project was completed as a team of four students, and my primary role was the manufacturing engineer. I took on this role to learn more about various manufacturing processes as I had little prior knowledge. My contributions consist of laser cutting the acrylic housing, 3D printing the photoresistor, and soldering and wiring the Arduino Nano to its various components (shown below). As a member of the group I was also jointly responsible for presentations, write ups, and team meetings.
I learned that teamwork and communication are crucial in any engineering project. Delegation of tasks and assignments, as well as assisting team members who are struggling was the key to the successful completion of our project in the allotted time frame. I also learned manufacturing skills that I had previously never been exposed to, such as laser cutting, 3D printing, and soldering. Along with teamwork, I gained new skills in professionalism through meetings with engineers for help with coding, and through presentations to project judges.
Initial Prototype CAD Drawing
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Small box housing electrical components designed to hang on rim of pot
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Casing is easily and quickly opened using a sliding door mechanism to access battery efficiently (made of acrylic)
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Aluminum arms are extendable and capable of folding inwards
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Ultimately decided against due to weight concerns as well as aesthetics
Final Product and CAD Drawing
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Circuitry housed in the small box next to the circle
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Circle illuminated by LEDs; color represents status of plant
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Right and left sides light up for moisture and light respectively
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This design was chosen over the prototype design as it conserves the most space and is the most aesthetically pleasing
Code Flow and Circuit Diagram
Code Flow
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Took original code of taking one reading at a time and developed more complex code. -
Created an array that stores 10 samples of both light and moisture readings independently and takes the average of those readings.
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The average reading for both light and moisture were then used to generate the correct light/moisture display that the arduino nano should be registering and outputting to the RGB LEDs.
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Two RGB LEDs that change color to represent light and moisture levels
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Displays blue, green, orange and red for above ideal, ideal, slightly below ideal, and far below ideal respectively
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Uses soil moisture sensor and photoresistor to input into Arduino
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Arduino outputs to LEDs
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Light Sensor:
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Powered by 3.3 V input
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Hooked in series to a 330 Ohm resistor in order to assign numerical values from the input
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Numerical values are taken by Arduino and output to the RGB LEDs to display the color that corresponds to that light leve
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Moisture Sensor:
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Powered by 3.3 V input
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Values taken in by Arduino and assigned to a numerical value
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These numerical values are read by Arduino and the color that corresponds to that value is displayed
Circuit Design
Arduino Calibration
*Our measurements for the Arduino's output when given some input (moisture or light)
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To create these graphs, we took soil with known moisture content and light of known intensity and read the output of these sensors.
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Both can be represented by exponential trendlines based on both our results and further research. Our light values were spot on but our soil moisture values were off due to the imprecise nature of the measurement technique.
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We used these graphs and experience doing the tests to set the values in the code for red, yellow, green and blue lights for moisture and light levels.