@nca78 I understand your concerns and I would like to further sensing in this area - that sps30 you mentioned looks like a prime candidate for a future upgrade. Currently I take 20 readings at one second intervals and then average them. This happens once every 5 minutes and gives a graph plot like this...... [image: 1563015389376-dust.jpg] This is using the Sharp GP2Y1010AU0F but done the right way, not like the build page ;)