Online Particulate Matter Sensor (no temp and Humid)

all credits to Chris for this great project: https://www.thingiverse.com/TheChrisP
i just made a small modification so that the display reads all 3 particle sizes and thus removed the temp sensor hole from the model.

For the Original instructions please read ChrisP's thing:https://www.thingiverse.com/thing:2320020

I do have some NOOB tips to share my experience as a total arduino noob. Perhaps it helps other builders.
Perhaps all is obvious for experienced people...i was not :-)

Downl