AirGuard

Back View
Vent
Clip
Front View
Exploded View of AirGuard
Side View of Switch
Lineup of 4 LED Colors
Speaker View

Inspiration

First responders put their lives on the line every day, often entering hazardous environments without knowing the full extent of the dangers. The leading cause of death among firefighters is occupational cancer, often diagnosed within just a few years of retirement. In 2023, 72% of IAFF member line-of-duty deaths were due to occupational cancer, and in Canada, that number is as high as 94%. Many of these cases stem from prolonged exposure to toxic gases released during fires. Despite wearing protective gear, first responders are still exposed to harmful gases that they cannot see, smell, or feel. Right now, there’s no real-time solution that tells them what’s in the air they breathe. We were inspired by the need for a proactive, real-time safety solution: AirGuard, a device that alerts firefighters to dangerous gases before they suffer irreversible health consequences. Firefighters and EMTs should never have to guess whether the air around them is safe.

What it does

AirGuard is a real-time gas detection system to protect firefighters from toxic, corrosive, and carcinogenic gases commonly present in fire emergencies.

It is a compact, wearable design that ensures that firefighters can use it effortlessly in high-stress situations. Clipped to a pocket of the user, it detects four hazardous gases: HCl, NH₃, H₂SO₄, and HCN using electrochemical sensors.

An LED display and speaker system provide immediate alerts, with color-coded lights for each hazardous gas and audio signals indicating gas type and concentration.

Wi-Fi connectivity allows data to be transmitted to an app such as Ascent, providing remote monitoring and alerts for command centers.

How we built it

Hardware: AirGuard features four electrochemical sensors, each with three electrodes for high-accuracy gas detection. A vent system ensures proper airflow, allowing smoke to enter and interact with the sensors. It also includes a switch for the sensors to be turned on and off.

Signal Processing and Control: The STM32 microcontroller functions as a dedicated data acquisition (DAQ) unit, receiving analog signals from the electrochemical gas sensors. It performs signal conditioning tasks such as amplification and filtering and then converts the signals into digital data using its built-in ADC. This processed data is transmitted to the ATmega328 microcontroller, which serves as the main controller. The ATmega328 analyzes the data, manages the alert system (such as activating LEDs or buzzers), and coordinates overall device operation.

Alert System: An LED display provides a visual warning, displaying a different color for 4 hazardous gasses. It also displays the concentration of the gas detected while a speaker beeps at varying intensities, increasing with the potency of the gas in the air.

Wi-Fi Integration: Real-time data can be transmitted to the Ascent app, enabling firefighters to receive mobile alerts and track exposure levels over time.

Challenges we ran into

A challenge was figuring out how to incorporate sensors to detect multiple types of gas. We tried to find a way for a sensor to detect various types of gas, but because it does not readily exist in the industry. Instead, we opted for 4 different electrochemical sensors that each detect a specific gas.

It was also challenging to figure out how the overall design of our device is, especially because we want to keep it small enough for firefighters to carry without adding extra burden. Given space constraints, we had to prioritize essential components like the sensors, alert system, and Wi-Fi module while ensuring the device remained lightweight and durable.

We wanted an indicator of the kind of gas in a way that was easy to interpret in high-stress situations. This is why we chose an alarm and color-coded system so that it is visible even in low-visibility conditions.

Accomplishments

We are proud of creating this device that ideally has a robust sensing and alert system that balances real-time responsiveness with its user-friendly simplicity. We were able to complete a fully realized design that includes detailed schematics and a custom printed circuit board (PCB) layout for manufacturability. Additionally, we are proud to include Wi-Fi integration for real-time safety monitoring, allowing first responders and command centers to stay informed in dangerous environments.

What we learned

While we learned many technical details, such as rendering and using CAD, along with how gas detectors work through electrochemical sensors and the signal conversion process, something else stuck in our minds. Human-centered design is important; firefighters need simple, instant alerts that work under extreme conditions. This was done by talking to real people in the industry and putting ourselves in their shoes, a process we will never forget.

What's next for AirGuard

We want to refine and prototype this device to move from concept to a fully functional prototype for real-world testing. In the future additional hazardous gases (e.g., CO, NO₂, SO₂) can be explored to integrate into our device for broader firefighter protection.

By connecting AirGuard via microcontrollers to an existing app like Aventis, exposure tracking can be improved through cloud-based logging and long-term health risk analysis.

We hope to see this device work with fire departments and safety organizations to bring this device into real-world use to protect our first responders!