Bruce Ford suggested that I looked at a paper on using these sensors for PM monitoring. One point of interest is that the sensor output has some link to ambient temperature, so this update adds a TMP36 sensor to the stripboard.
It’s a fairly simple addition, one 3-pin device and a wire to the A1 input on the Nano.
In addition to the parts listed in the previous post : http://connectranet.co.uk/wp/2016/09/23/sharp-dust-sensor-arduino-nano-and-2×16-lcd
- TMP36 Sensor (TO-92 Package)
Add the TMP36 to the strip board…
Pin 1 to row 8 of the stripboard (+5v)
Pin2 to row 7 (temp sensor output)
Pin3 to row 9 (Gnd)
then add a wire from Row 7 to A1 on the Nano.
The Temperature can then be read from A1 using AnolgRead(1).
The output voltage of the TMP36 is 10mV / degree + 0.5v so 25c = 0.750v
temp = ((analogRead(1) * 5 /1024)-0.5)*100;
using the Temperature reading
I don’t have any information or calibration data that suggests how to adjust the reading to account for temperature so the next step is to try sealing the sensor with clear tape to keep the dust level inside constant, then vary the temperature to see how this varies the dust sensor output.