A WiFi-Enabled, Solar-Powered Particle Analyzer Housed in a Seashell
This low-cost monitoring station sends particulate matter sensor readings to your phone.
Measuring airborne particulate isn’t usually the first thing on your mind, and if doing so means having an unsightly — depending on your point of view — monitoring station in plain sight, this could make doing so even less attractive. To encourage others to participate in at least observing the environment, “rabbitcreek” made a solar particle analyzer that’s cleverly disguised as a large seashell.
The shell not only looks good, but provides a waterproof housing for the electronics inside. This includes an Adafruit HUZZAH32 ESP32 Feather board and charging circuitry, along with a Honeywell laser-based particulate matter sensor for actually collecting environmental data. This info is then relayed to the Blynk app over WiFi. Outside a 2.5W, 5V solar panel supplies power to the device, making it an entirely self-contained monitoring unit.
In order to save power, the station uses an Adafruit TPL5111 low power timer breakout, which sets a pin to high periodically — in this case every two hours — turning it on only for incremental readings. This, with the solar charging circuitry for an 18650 LiPo battery, could make the project an excellent template for other low-power devices. Notably, if two hours is too long of an interval, the reset timer can be set to activate as fast as once every 100ms.