Relation between pwm ratio and dust concentration

[chupachupbum]

Do you have any explanation or reference for this formula?

MySensors/examples/DustSensorDSM/DustSensorDSM.ino

Line 136 in f4fd69e

long concentration = 1.1*pow(ratio,3)-3.8*pow(ratio,2)+520*ratio+0.62; // using spec sheet curve

[mfalkvidd]

You could try posting in the forum. Might be a bigger chance that your question is seen by someone who can answer.