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Weather Station Hardware => Air Quality Sensors => Topic started by: watsonm on August 19, 2022, 05:11:39 AM

Title: PMS5003 Orientation
Post by: watsonm on August 19, 2022, 05:11:39 AM
Folks,

I have the PMS5003 Particle Sensor and have it successfully attached to my weather station. I am now looking to install it on a wall outside rather than by my open window ledge.

Obviously it is not weather secure so I have decided to re model a fridge food container to house it. (SImilar to the Airlink unit with a section at the "bottom" of the container removed)

My questions are:

1) Does the air flow from large aperture to the four small holes. I believe it does as I have tried with the smoke from a match but because the flow rate is so low it wasn't conclusive.

2) Having watched a video of a strip down of one of these units for clearing and seeing the dust inside the unit I wanted to know whether it would be better to mount it with the exit holes at the bottom of the unit (hopefully reducing the amount of dust settling on the photo diode)

Any comments?

(Also posted in CumulusMX forum)
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Title: Re: PMS5003 Orientation
Post by: davidefa on August 19, 2022, 05:44:11 AM
I think the best position ( regarding dust build up ) is with the sensor facing down.
I think the vertical position with the air vents on the bottom is ok too ( regarding dust build up ) and has the advantage of permitting free air circulation and easy rain protection
Title: Re: PMS5003 Orientation
Post by: watsonm on August 19, 2022, 05:55:34 AM
David,

Many thanks for your opinion.  I had thought about vertical before and after your comment went back to the product sheet.   Came up with this in the installation section.

2) The best way of install is making the plane of inset and outset closely to the plane of the host. Or some shield should be placed between inset and outset in order to prevent the air flow from inner loop.


Not exactly sure what the first sentence means... The host could refer to the shroud or protecting unit that the sensor is placed in. The second sentence I can understand.
Title: Re: PMS5003 Orientation
Post by: davidefa on August 19, 2022, 06:14:49 AM
I think it refers to the opening on the container box:
- if the air inlet/outlet of the sensor are flush with the opening on the box, nothing is required ( see purpleair: https://www2.purpleair.com/products/purpleair-pa-ii-flex?variant=40067721396321 )
- otherwise a separator is required ( to separate inlet and outlet fluxes )

P.S.
I'm 'reworking' my sensor too: adding a a second sensor and changing the orientation ( the poor man's purple air )
Title: Re: PMS5003 Orientation
Post by: watsonm on August 19, 2022, 08:13:58 AM
Ok thanks David... Understood.