Written by Vansh Arora, 17, 12th Grade
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My name is Vansh Arora, and I have developed an economical device that continuously monitors carbon dioxide, carbon monoxide and fine dust levels, with the readings sent to a dashboard accessible from any web browser. I am a secondary school pupil, and I built the device myself, learning the hardware and software required along the way.
This instrument, no larger than a smartphone, has found its permanent place in the Humayun's Tomb museum, where it performs a task no one visiting the place ever does: it counts the invisible. Every few seconds it monitors the carbon dioxide, carbon monoxide, and dust particles present in the environment around it, then sends the numbers to a constantly updated dashboard available on the Internet.
The invention came about thanks to a question that belongs to two disciplines that rarely overlap: engineering and conservation of heritage sites. Old buildings are very vulnerable to environmental conditions; increased carbon dioxide may indicate insufficient ventilation, dust settles on walls and speeds up the process of decay, and temperature and humidity changes gradually destroy the building's structure. While conservationists are aware of all these threats, what has usually escaped them are tools to detect them without cease.
The device includes an ESP32-C3, a low-power Wi-Fi microcontroller, connected to three sensors that detect various types of danger. One is the Sensirion SCD40 that checks for CO₂ emissions alongside the measurements of temperature and humidity. The MQ-7 sensor detects carbon monoxide: an invisible gas produced where no air flow is present. The optical sensor by Sharp monitors particulate matter down to PM2.5, which is responsible for harm to materials and humans.
Rather than storing the values on the chip, I transferred these readings to a cloud database, which logs in and uploads the latest value every few seconds. A caretaker can monitor changes in the room during the day, such as a sudden increase in carbon dioxide levels as the gallery gets crowded or an increase in dust as someone leaves the door open, without entering the room at all. One-off snapshots become a continuous stream of readings.
The construction of the project was not easy. Creating three sensors with diverse output values sharing one microcontroller involved resolving analogue and digital signal issues on limited equipment. The carbon monoxide sensor had to be calibrated in clean air before any readings could make sense, and each of the sensors had to be adjusted individually for conversion calculations. Finally, as the cloud software refused to fit into the default memory allocation of the chip, I had to modify the storage allocations in my device.
Also, the monitor picks up a common theme in my previous works, in which I studied the behaviour of air in constructed structures, including modelling of air movement and pollutant transport using computer software. Here, I developed the technology from theory to practice since computer simulations would predict the behaviour of air, but the monitor records the actual behaviour of air.
This has been used in collaboration with the Aga Khan Foundation for 6 galleries, an organisation working on the conservation of monuments across different countries, thus placing the prototype in an area where its readings affect the conservation of the structure.
I made sure to put things into perspective. It must be noted that a prototype is just that, a start and certainly not a finished product, and issues related to accuracy and durability are still open for discussion. I believe in the scalability of my invention since it allows for multiple low-cost devices to be used in an area instead of one expensive station looking at only one room.
