Many, of the items that make up the w|edge folk:land Survey Project are handmade. The tent is hand sewn with Ripstop nylon, the poles are cut to size from furniture grade pvc pipe. As the project moves forward, I'm focusing on the fabrication of more tools for folks to interact with as they examine our shared landscape. The next set of posts will highlight the tools I have made thus far as well as those yet to come.
The Particulate Matter Sensor has three lights. This project was built using instructions provided by the EPA. "The amount of PM pollution is determined based on the amount of time the sensor is detecting particles. The Arduino then lights up the LEDs based on how many particles are seen. 1 LED for a low number of particles, 2 LEDs for a moderate amount of particles, and 3 LEDs for a high amount of particles... Since warm air rises, a heater causes air to flow through the sensor. This is why the sensor must be mounted vertically. An LED shines light on the particles and the amount of light that is deflected by the particles is measured by a light receptor. This type of particle detection generally sees particles greater than 1 micrometer, which makes the sensor more sensitive to larger particles like dust and less sensitive to very small particles formed in smoke."
Information above quoted from directions for building your own PMS. https://www.epa.gov/sites/production/files/2014-12/documents/sensor-kit-instructions.pdf