I’ve got problem with (I think) too high measurements with PPD42NS. During 30s I have about 25s of LOW state on P2 pin. I checked my connections many times, compared it with different documents, pages about PPD42NS so I’m sure it’s connected good. I checked also voltage on P2 with voltmeter. Of course voltage was changing all the time, but very rarely I saw it over 3-4V. Most of time it was around 1-2V, sometimes below 1V.
Seeing such results I thought about voltage min rates. For PPD42NS low state is BELOW 0,7V. But for Arduino low is BELOW 1,5V. There’s 0,8V of gap. This can make measurements not accurate, because if 42 gives for example 1V (which is not low state for it) Arduino shows that it’s low state. Can it be a problem? If yes, how can I multiply by 2 (from 0,7 to 1,4V which is max for low state in Arduino) voltage that comes from 42 and also make sure that it won’t be over 5V?
Or… my measurements are correct and my air is so bad? 
Because what’s interesting, all measurements are very similar. It’s always between 24800ms and 25100ms. Always…
