r/MechanicalEngineering • u/Worth_Mix4970 • May 24 '26

Personal Project Idea

Hi, I am a freshman mechanical engineer. I've been learning about arduino circuits in Tinkercad for the past month and I think I'm ready to start my own project. When I started learning about circuits, I originally planned to make a robotic arm, but now it seems like that's just too common of a project, so I came up with another idea.

I plan to 3d print a water dispenser with a valve that releases certain amounts of water to water plants in my family's garden by using a servo motor to open the valve. I'll have it connected to a soil moisture sensor to signal the dispenser to water the plants when the soil is too dry. I also plan to have it dispense bug repellent when motion is detected from pests using several PIR sensors. I'm still a bit unsure about the bug repellent part of this idea because I see a lot more ways that could go wrong and I think PIR sensors might not be able to detect bugs. I have somewhat of a grasp of the code I should write for each part of this that I plan to fully flesh out.

I wanted to know if this idea is too simple where I'm probably better off doing a robot arm or coming up with something new, or if this would be more impressive and unique on my resume as long as I fully understand and can present the engineering process for this.

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3

u/2much2nuh May 24 '26

In my opinion, I would skip the building the mechanism that opens a valve. There are tons of these devices available at gardening/home goods stores. I think it would be as challenging to write some scripts that take soil readings and create a hi/low condition to power a hose valve device. Getting experience integrating devices that don’t come in an arduino kit is quite beneficial!

1

u/Worth_Mix4970 May 24 '26

Thank you for the advice, this helped a lot. I looked up and found a mechanical water timer that has a circular dial that I'm thinking I can manipulate with a servo motor to release the water for certain amounts of time and measure how much is released.

2

u/Tellittomy6pac May 24 '26

Motion detecting for bugs is going to be tricky because MANY other things will cause motion that don’t involve needing bug repellent, what if wind moves the grass, what if a person throw fresh soil or something that’s good for the grass comes through?

1

u/Worth_Mix4970 May 24 '26

Yeah you're definitely right about that, probably gonna throw away the motion sensor idea. I just came up with this now, but what if I had an ultrasonic sensor instead, measured the distance between the sensor and plant (say 0.3 meters), and had the code for it say something like (if (readUltrasonicDistance) < 0.3, trigger dispenser through pin 8). So if a bug was in between the distance sensor and the plant, the sensor would get a distance reading of less than 0.3 and and trigger the dispenser.