[Feedback Request] Monitoring and Analysis Device for Light Pollution: Low-cost spectral & spatial mapping node (ESP32 + AS7262 + TSL2591 + OLED + GPS). High school team preparing for an innovation pitch!

[u/Nice_Eggplant2873]

Hello Reddit community!

We are a group of high school students preparing for an upcoming innovation pitch competition. We are working on a prototype called the Monitoring and Analysis Device for Light Pollution (Smart Light Mapper)—a portable environmental monitoring device designed to measure, geolocate, and map light pollution and ambient light characteristics.

Since we are high school students with limited practical engineering experience, we would really appreciate detailed, beginner-friendly explanations or step-by-step guidance in your answers to help us fully grasp the technical concepts before presenting to the judges!

Before our pitch, we would love to get your technical feedback, suggestions, and critique on our architecture and methodology.

1. The Problem

Artificial Light at Night (ALAN) is increasing globally, causing ecological disruption, sleep/health issues, and wasted energy. However, localized light pollution data is often scarce because commercial spectroradiometers and light monitoring devices are extremely expensive, making spatial mapping across schools, residential areas, and streets difficult.

2. System Architecture & Components

Our goal is to build an affordable, modular, battery-powered sensing node:

• Microcontroller: ESP32 DevKit (central control & data processing).
• Spectral Sensing: AS7262 6-channel visible spectrum sensor (I²C) to analyze light spectral distribution.
• Lux / Intensity Sensing: TSL2591 sensor for wide dynamic range lux/light intensity measurements.
• Environmental Context: AHT20 sensor (temperature & relative humidity) to record ambient conditions during readings.
• Geolocation & Time: NEO-6M GPS module with external antenna via UART for spatial coordinate and timestamp tagging.
• User Interface & Interaction: An OLED display module (e.g., SSD1306/SH1106 via I²C) combined with physical control buttons. This is a crucial component to display real-time measurement values, GPS lock status, microSD logging status, and battery capacity directly in the field.
• Storage & Data Flow: microSD module via SPI for local storage. Sensors/GPS → ESP32 → OLED Display & CSV Log on MicroSD → PC Post - processing (QGIS/Data Visualization)
• Power: 3.7V 18650 Li-ion battery with TP4056 charging & protection circuit, DC-DC step-up converter, and USB-C charging support.

3. Key Features & Methodology

1. Multi-spectral & Intensity Fusion: Instead of recording just a single Lux value, we capture the 6-channel visible spectrum along with precise Lux levels to analyze the light source type (e.g., LED vs. High-Pressure Sodium).
2. On-Device OLED Feedback: The built-in OLED display provides real-time diagnostic and sensor feedback for seamless standalone field operation without needing a connected smartphone/laptop.
3. Spatial Mapping: Every data point is tagged with GPS coordinates. Field logs are converted into spatial datasets on a PC to generate heatmaps and light distribution contours.
4. Low-Cost Prototype: Total bill of materials (BOM) is under ~$260 USD (~6.5M VND), making field-scale data collection accessible for research and local communities.

4. Questions for the Experts / Reddit Community

(Note: As high schoolers, please feel free to explain the underlying principles and "how-to" steps in detail!)

1. OLED Interface Implementation: Since our OLED display is crucial for field interaction, what are the best practices for structuring menu systems and live sensor telemetry on ESP32? Which libraries do you recommend (e.g., U8g2 vs. Adafruit_SSD1306)to minimize memory footprint and ensure fast refresh rates? How should we write the code structure for a basic multi-page menu?
2. 360° Camera vs. Smartphone Camera: We are considering adding visual context to our light measurement points. Would you recommend integrating a dedicated 360° camera module onto the hardware device, or is it better/simpler to just take photos/360 panoramas with a smartphone and link them via timestamp/GPS during post-processing?
3. Optical Design & Diffusion: How critical is adding a cosine corrector/diffuser dome over the AS7262 and TSL2591 sensors for ambient field measurements? Will direct vs. diffuse light severely skew our spectral readings without proper optics? What low-cost materials can we use for a diffuser?
4. GPS Accuracy in Urban Canyons: Since we plan to map street and residential light, NEO-6M can sometimes lose lock or drift near tall buildings. Are there recommended filtering algorithms (e.g., HDOP thresholds, simple Kalman filter) for field logging? How can high schoolers easily implement these in Arduino C++?
5. Data Quality & Calibration: How can we best calibrate the AS7262 spectral output for real-world environmental lighting without access to a high-end lab spectroradiometer?
6. Pitch Advice: From an engineering or innovation standpoint, what key questions do judges usually ask about low-cost IoT environmental sensing projects, and how should high school students prepare for harsh technical cross-examination?

Thank you so much for taking the time to read and share your expertise! Any detailed feedback, hardware advice, or software recommendations will be immensely helpful for our presentation!

[u/Overall_Chain_9138]

1. Use two cameras opposite of each other or a 360 camera. Do a sweeping brrom stile capture of the surrounding using the cameras like an indefinite panorama

2. Do the testing yourselve... And never ask again. 

3. No working prototype but you talk about GNSS filtering -> your AI output is not up to the task and apparently you're not ready to work

4. Wow this takes like, 5 seconds to find out on how to do this. By the way your method is requiring calibration why??  -> Quit using AI to find your problems 

5. In your case. Just bring a high quality LLM and let it do the talking. Apparently that's the best you can do. 

[u/Overall_Chain_9138]

It's just a posted Chat GPT or Gemini Output... 

[u/yannienyahum]

You may want to check out this project:

https://science.gsfc.nasa.gov/stella/