[eBender] was travelling India with friends, when one got sick. Unable to find a thermometer anywhere during COVID, they finally ended up in a hospital. After being evacuated back home, [eBender] hatched an idea to create a portable gadget featuring a few travel essentials: the ability to measure body temperature and heart rate, a power bank and an illumination source. The scope evolved quite a lot, with the concept being to create a learning platform for environmental multi-sensor fusion. The current cut-down development kit hosts just the air quality measurement components, but expansion from this base shouldn’t be too hard.

This project’s execution is excellent, with a hexagon-shaped enclosure and PCBs stacked within. As everyone knows, hexagons are the bestagons. The platform currently hosts SCD41 and SGP41 sensors for air quality, a BME688 for gas detection, LTR-308 for ambient light and motion, and many temperature sensors.

On top sits a 1.69-inch IPS LCD, with an OLED display on the side for always-on visualization. The user interface is completed with a joystick and a couple of buttons. An internal blower fan is ducted around the sensor array to pull not-so-fresh air from outside for evaluation. Control is courtesy of an ESP32 module, with the gory details buried deep in the extensive project logs, which show sensors and other parts being swapped in and out.

On the software side, some preliminary work is being done on training TensorFlow to learn the sensor fusion inputs. This is no simple task. Finally, we would have a complete package if [eBender] could source a hexagonal LCD to showcase that hexagon-orientated GUI. However, we doubt such a thing exists, which is a shame.

There are many air quality sensors on the market now, so we see a few hacks based on them, like this simple AQ sensor hub. Let’s not forget the importance of environmental CO2 detection; here’s something to get you started.