Particulate Sensor

[willbish]

Im in the market and looking for recommendations for a particulate sensor that will connect with Loxone and shut down the MVHR should the neighbours smoke cause us too much bother.

Farnell have a sizeable range and Im drawn towards the Honeywell model.

I think I have two options

1. Sample the outside air, broadly in the area of the intake.
Issues are finding somewhere to keep the sensor which is dry and with power.

2. Sample the air from inside the MVHR ducting.
Issue is none of the sensors Ive seen, so far, have a narrow intake pipe which can be put into the MVHR ducting. So I would need to alter/fashion something.
Other disadvantage with this method is the MVHR would need to be running for the sensor to have a fresh (or not) sample of air. This may involve running the MVHR for a short period every 15mins or so after the sensor has been activated. Not difficult to do in Loxone but may undermine my attempts to keep wood smoke out of the house.

Has anybody attempted something similar?

[Faz]

Is it an existing issue bud or a what if?  Must be fairly extreme if existing tbh.

 

Haven't looked into how they work but I imagine that the particulate sensors would offer on or off which basically shuts down your whole system - I wouldn't have thought this the ideal solution.

[SteamyTea]

Played with one of these, connected to a Raspberry Pi.

http://plantower.com/en/content/?106.html

 

It has a built in fan, but I am told the accuracy soon drops off.

 

Some of those Honeywells seem good value.

[willbish]

32 minutes ago, Faz said:

Is it an existing issue bud or a what if? 

It's a what if, thought I'd first fix the cabling initially, have decided I might as well do the whole install whilst I'm at it.

 

34 minutes ago, Faz said:

I imagine that the particulate sensors would offer on or off 

They measure the proportion so can set a threshold in the Loxone.

 

34 minutes ago, SteamyTea said:

Played with one of these, connected to a Raspberry Pi.

http://plantower.com/en/content/?106.html

 

It has a built in fan, but I am told the accuracy soon drops off.

 

Some of those Honeywells seem good value.

Would love the time to learn and tinker with a Raspberry Pi, unfortunately deadlines are looming.

 

With the Honeywell I'd need to modify to get a sample inside the duct. 

I'm thinking very small funnel glued to the unit, then small hose which would pierce the ducting...

[TonyT]

 

https://edinburghsensors.com/products/oem-co2-sensor/boxed-gascard/

 

[willbish]

On 22/10/2021 at 21:32, TonyT said:

 

https://edinburghsensors.com/products/oem-co2-sensor/boxed-gascard/

 

They appear to only do Gas sensots but I've shot them an enquiry email.

 

CVC were interested in the idea but ideas from them have since dried up.

[PeterW]

On 22/10/2021 at 21:25, willbish said:

With the Honeywell I'd need to modify to get a sample inside the duct. 

I'm thinking very small funnel glued to the unit, then small hose which would pierce the ducting...

The Venturi effect would do the opposite and pull air the wrong way - fans on these sorts of units are tiny. 
 

Can you not use a plenum box on the intake and install the sensor in that..?

 

The other low tech way is install activated carbon filters in a pre filter box - should reduce a substantial amount of the smoke. If you want slightly more high tech then build an ionisation box on the way in too. 

[willbish]

@PeterW I see what you mean. The unit needs to be sat within the air it's sampling.

 

I'm pretty tight for space to be adding boxes.

 

Perhaps I can find somewhere discreet in a room, probably a bedroom, not far from the input terminal. 

 

Could that be falsely triggered by aerosols or any other bedroom activity?!