Dust sensor and GrovePi

Archives GrovePi
1

Hi,
I have a Dust sensor and GrovePi+ and I would like to translate the measure unit from pcs/0.01cft to ug/m^3.
I have used the code from grove_dust_sensor.py


try:
		[new_val,lowpulseoccupancy] = grovepi.dustSensorRead()
		if new_val:
			print lowpulseoccupancy
		time.sleep(5)

the value of lowpulseoccupancy is already in pcs/0.01cft ?

Thanks

2

Hey,
lowpulseoccupancy is the number of ms in a 30 second period for which the sensor data was low which indicates a reading from the dust sensor. If you check the wiki here: http://www.seeedstudio.com/wiki/Grove_-_Dust_Sensor, to change that into concentration just do this:
ratio = lowpulseoccupancy/(sampletime_ms10.0) # Integer percentage
concentration = 1.1pow(ratio,3)-3.8pow(ratio,2)+520ratio+0.62 #using spec sheet curve

-Karan

3

Thank you karan for your reply.

With your code, concentration is in pcs/0.01cf ?

Do you know how translate it to ug/m^3?

Thanks

4

The datasheet says the concentration is in .01CF which is 283ml or 1 cubic feet. 1 cubic feet is 0.0283168cubic meter so you can just use a multiplying factor to convert it from cubic feet to cubic meter.

-Karan