Final Project
I worked on defining my final project idea and started getting used to the documentation process. It all begins in Week 1, where you can find my initial idea, some sketches, and links.
Curious to see my first sketches and research process?
Check them out here
Here’s an example of my concept:
A CO₂ Infopoint seamlessly integrated into the wall for Companys and open plan offices.
Time Line
2D and 3D Modeling
04.02.2025
The first prototype consists of an elegant wooden casing with a diffuse acrylic glass panel. This panel features a bee icon with a targeted opening for the CO₂ sensor, ensuring more accurate measurements.
Inside, a precisely fitting PLA frame securely holds the electronics and circuit boards. It is designed to slide into place without additional fasteners, staying in position due to its exact fit.
A dedicated groove accommodates the LED strip, while a subtle elevation in the center optimally positions the CO₂ sensor.
The LED strip emits a soft, diffused glow across the acrylic surface, preventing glare while creating a pleasant and evenly distributed light.
The acrylic panel itself is securely attached with magnets and includes two small foot supports to ensure a perfectly aligned installation.
At the bottom of the wooden frame, polygonal openings allow for clear sound output from the speaker. The rear side features carefully placed cutouts, making it easy to mount the enclosure flush against a wall.
Focus in March: PCB Design
In March, I primarily focused on designing the PCB for my final project. I reused the design of my polygon to define the cutout shape of the board, ensuring that it fits perfectly into my product.
First PCB Issue: Incorrect Voltage
With my first PCB version, I discovered that the voltage was incorrect. The CO₂ sensor requires a 5V supply, but I had mistakenly connected it to a 3.3V line. This oversight led to functionality issues, which I plan to fix in the updated design over the next few weeks.
Custom PCB for LCD Screen
For my LCD screen, I designed a custom PCB using the same polygon shape as the main board to maintain visual consistency. I used horizontal (lying) headers to connect the screen with flexible cables, allowing for more adaptability when integrating it into the housing.
Inlay Testing in April
In April, I tested the inlay for my final project and placed the PCB inside it for the first time. This allowed me to check the fit and alignment of the board within the housing and make any necessary adjustments early on.
For each component, I plan to design a dedicated PCB that fits precisely into the polygon-shaped slots of the 3D-printed parts. This approach ensures a clean and well-integrated assembly within the final product.
Materials
| Electronic Link | Picture | Price | quantity |
|---|---|---|---|
| 1. CO2 Sensor MQ-135 |  |
Price: 2,80€ | 1 |
| 2. PCB-Pixel-LED Strip |  |
Price: 8,29€ | 1x2m |
| 3. Joy-it com-lcd 16x2 Display-Modul 6.6 cm (2.6 Zoll) 16 x 4 Pixel |  |
Price: 4,99€ | 1 |
| 4. Xiao ESP32-C6 |  |
Price: 8,45 € | 2 |
| 5. Sound Output |  |
Price: 3,80€ | 1 |
Material List Updates (February – April)
Between February and April, I made several updates to my material list. Firstly, I replaced the originally planned CO₂ sensor—which was quite expensive—with a more affordable alternative. While this new sensor requires a 24-hour warm-up period, it consumes significantly less power afterward. I’m currently evaluating whether this option performs better overall. Additionally, I swapped out the Bluetooth transmitter for a Xiao ESP32-C6, which offers broader connectivity options and suits my project’s needs more effectively.
To improve clarity, I built my first prototype shell and created an electronic overview:
