Jisu's Final - Still a Flower (temperature and Humidity Sensor With Lights Signal)

For this project, I wanted to create something I genuinely needed. The first thing I bought when I came to the US was a humidifier. The dryness here was such a drastic environmental change for me. As winter approaches, I found myself wanting to know the exact humidity and temperature of my space, and I also wished for a small companion-like presence in my room, something like a plant.

One day, while these ideas were floating around in my head, DJ Okawari’s Flower Dance came on my playlist. The track opens with a dialogue from a 1960s film, Space-Men (released in the US as Assignment: Outer Space), and that scene gave me the exact vision I needed.

In the scene, a woman born on a spaceship doesn’t know what a “flower” is. On Earth, flowers were romantic symbols, but in space, they’re just called “Diasporas”—functional devices that convert hydrogen into breathable oxygen. But the man know what flowers meant on Earth.

He says: “But I still say they’re flowers”

And then he said “you won’t have to send them anywhere. I’ll pay for them, and then, I’ll leave them here, for you.” He gifts her the emotion and meaning from Earth. She understands his intention and smiles.

That moment made everything clear. I didn’t want to just display temperature and humidity readings. I wanted to create something that, like a plant, stays by my side and breathes the same air in my space, responding to it.

So this project goes beyond measuring humidity and temperature. It’s a small object that reacts to the air in my space and glows like a tiny living thing, offering me comfort.

Arduino board

LCD display with I2C backpack

temperature and humidity sensor

button led

Jumper wires

Breadboard

USB cable for power

acrylic plates + dome

First, I connected the LCD and backpack to display temperature and humidity, then connected the temperature and humidity sensor. After that, I wired the button and LED, using the code.

At the beginning, I tested with a different example code instead of helloworld_i2c and spent about an hour troubleshooting, thinking the LCD wasn’t working.

For the humidity sensor, it would have been much easier if I had purchased the jumper wires (or connector cables) that come as an option when buying the sensor. I recommend getting those together to save time on wiring.

I 3D-printed the plant object, then bought an acrylic dome and acrylic sheets to go on top. I cut the acrylic and assembled everything together. I’m the type who just dives in and makes things by hand, so I don’t have many photos of the process. I laser cutted a section in the acrylic for the LCD panel to fit through, and engraved “if(dry){hydrated()}” on front sides. (It’s not very visible now that it’s done, but I added it to bring in some emotional touch.)

For the base box, I used 1/8-inch thick acrylic. To ensure the light would illuminate only directly beneath the plant object, I built the enclosure with black acrylic, then topped it with mirrored acrylic. I added ledges to keep the lid securely in place without shifting. I also drilled a 1.4mm hole to allow just the cable to pass through cleanly.

P.S. In person, you can see the details—I made precise measurements and added ledges for the lid. I’m proud of how carefully I crafted it.

I set up the code so the LED color changes based on humidity levels. When I measured my room’s humidity, it usually fluctuated between 20–30%, but comfortable humidity is over 35%. So I adjusted the ranges to fit my environment.

1. Below 20% → Red (too dry, need humidifier)
2. 20–30% → Orange/Yellow (dry, needs attention)
3. 30–35% → Green (getting better)
4. 35–40% → Blue (comfortable, goal reached)

Since my room rarely goes above 40%, seeing blue became a small achievement.

I turn on the humidifier and fall asleep watching the plant shift from green to blue.

And like changing an LP record, I designed it so you could change the plant object based on your mood or on season.

I took this after I got home.

If there’s one thing I’d change, it’s that I didn’t know the humidity sensor had a built-in green LED. If I had known that beforehand, I would have designed the box structure differently. The sensor’s light overlapped with the plant object, creating an unintended visual element.

I also realized during assembly that placing the LCD panel at the top might have worked better. The engraved text would have been more visible that way. Next time, I’ll examine all the components more carefully before starting.

But when it came to proportions, I tried many iterations. I bought four different sizes of acrylic domes just to find the one that fit best with the object. With all the care I put into it, this is still a flower to me.

https://drive.google.com/drive/folders/1J3W8q8kzUqmo9FFRmaQ4vjpsD6fBMZOw?usp=drive_link

Future Development:

If I get the chance, I'd love to add IoT functionality so the device can send alerts to my phone when the air gets too dry. It would be nice to receive a notification even when I'm not in my room, reminding me to turn on the humidifier before I get home.