Refreshing the topic. I had installed a home-made air quality sensor using the sensor from Sharp (GP2Y1010AU0F/GP2Y1010AU0F posted in this forum) and a MQ131 sensor (for ozone). I’ve been logging for a while now but don’t get any exciting result. I do readouts either every 1 second or do a 10-sec average and log to a file.
I’ve noticed a difference between two sensors: GP2Y1010AU0F has an offset of about 0.4-0.5 V which is what the specifications say. The GP2Y1010AU0F has no offset (or 0.04-0.05 V).
I’ve attached a log for one day from both sensors that are installed side by side.
Either our air is that clean or something does not work OK. Can someone post a log for one day from the PurpleAir sensor? I wonder if the dynamics is more interesting there.
PS: I made a smoke from a candle and both sensors reacted immediately. So they should be connected alright. ??
Smoke is a good test. You may want to check the sensitivity specifications for those sensors to calibrate your expectations for general air quality sensing.
With the Napa wildfires, I have to say that the Purple Air sensor was a good investment. The air quality around here has really sucked the last several days.
//Air Quality
//==========
$purpleair2_5 = '%purpleair2_5%'; //Value of 2.5 micron particle measure from purple air sensor (see in WD under setup, advanced/misc)
$purpleair1_0 = '%purpleair1_0%'; //Value of 1.0 micron particle measure from purple air sensor
$purpleair10_0 = '%purpleair10_0%'; //Value of 10.0 micron particle measure from purple air sensor
$purpleairaqi = '%purpleairaqi%'; //AQI (air quality index) value from purple air sensor
$purpleairaqidescription = '%purpleairaqidescription% '; //AQI description (e.g Good, moderate)
$purpleair60minmean10_0 = '%60minmeanpurpleair10_0%'; //Last 60 minutes average PM 10.0 value
$purpleair60minmean2_5 = '%60minmeanpurpleair2_5%'; //Last 60 minutes average PM 2.5 value
$purpleair24hourmean10_0 = '%24hourmeanpurpleair10_0%'; //Last 24 hours average PM 10.0 value
$purpleair24hourmean2_5 = '%24hourmeanpurpleair2_5%'; //Last 24 hours average PM 2.5 value
$purpleair60minmin10_0 = '%60minminpurpleair10_0%'; //Min value in last 60 minutes PM 10.0 value
$purpleair24hourmin10_0 = '%24hourminpurpleair10_0%'; //Min value in last 24 hours PM 10.0 value
$purpleair60minmin2_5 = '%60minminpurpleair2_5%'; //Min value in last 60 minutes PM 2.5 value
$purpleair24hourmin2_5 = '%24hourminpurpleair2_5%'; //Min value in last 24 hours PM 2.5 value
$purpleair60minmax10_0 = '%60minmaxpurpleair10_0%'; //Max value in last 60 minutes PM 10.0 value
$purpleair24hourmax10_0 = '%24hourmaxpurpleair10_0%'; //Max value in last 24 hours PM 10.0 value
$purpleair60minmax2_5 = '%60minmaxpurpleair2_5%'; //Max value in last 60 minutes PM 2.5 value
$purpleair24hourmax2_5 = '%24hourmaxpurpleair2_5%'; //Max value in last 24 hours PM 2.5 value
New graphic of aqichart.gif (graph) and aqi.gif (gauge) also available.