Scheduling fresh air intake & air filtration?

When I’m at the space I often forget we have the fresh air intake & air filter in the main room, and the when I wake up the next day I always seem to end up a bit sniffly. I don’t know how much the wider membership is aware of & uses the air filtration systems either.

To try and maintain good air quality at all times, would it be possible and useful to have the air intake & filter run on a timer or schedule? E.g. set them going for a couple of hours every morning, afternoon, and evening?

Quite happy if the answer is “no that’s stupid”, but figured it’s worth talking about.

My unqualified thoughts / suggestions:

Fresh air intake
We might be able to wire in a mechanical timer could work? E.g. GREENBROOK T100A-SCR MECHANICAL TIMER (4883R)

Air filter

There are some little remote controls powering our air filtration unit. I wonder if it might be possible to reverse engineer / emulate a remote, and emit equivalent radio signals from an arduino on a given schedule?

Or for a slightly more destructive approach, replace the momentary switches on a remote with an arduino contraption that emulates whatever combination of button presses we’ll need to get the filter running how we’d want it to run.


This is an excellent idea! The original controller for fresh air was by the light switches but since being moved it’s a bit out of sight out of mind.

The fan used is rated to run for maximum two hours at a time, as are a lot of generic inline fans. So I’d say have it operate on a cycle throughout the daytime, giving the fan say 2h on 1h off. My guess is they run the motor a touch hot.

Could you keep the countdown timer though? I got that for the space and if we don’t need it for fresh air it would be great for controlling the halogen heaters this winter!

Hacking the filter could be done by checking if the remote works over 433mhz - in our last space I used an Arduino to control remote control sockets as there’s a library for 433mhz transmission, it just requires a simple transmitter board. I’d be happy to help with this if you would like!

Agreed this is a great idea. I presumed we hadn’t done it like this for when it gets bitterly cold in winter. But I agree, the air quality in the space is probably the bigger issue.

I was going to suggest we just wire the fans into the light switches, but I wasn’t aware of the 2 hour run time.

R.e. The air filter, my personal preference would for this to be on manual mode still. They’re very noisy and so I only tend to turn it on if there’s no one in the space I’m talking to. Mark pointed out that a lot of people probably don’t use it as a) they don’t know what it is, and b) it was broken for many months so didn’t do anything anyway.

If I got overruled though, I’d suggest it turns on (at say 1am?) for an hour each day, just so it’s cleansing the room occasionally while no one’s about.

I’d suggest whatever mechanism we install for the main air fan, we also install for the fan in the cnc room, which is sucking, then you’d get some air flowing through the space. If that’s going to make the cnc room become a mess, I’d propose we install one of the bits of ducting we bought recently to port the suction into the main wood room.

@Cone there was suggestions we get rid of the heaters entirely based on cost, and fire risk, considering on several occasions last winter I saw people with 2 or 3 heaters pointed at themselves and then found them a few hours later still turned on, but the person having left. Having them in fixed locations on a bump timer is the middle ground argument though, which I would support.

Tied in with the lights is a good shout, we could probably connect the timer above into the lighting circuit on a shorter frequency (perhaps 30m on/off) and then the timer will then only run when the lights are on.

The shorter frequency means someone who is only in for an hour will still get a bit of fresh air and it won’t burn the motor out if someone is in all day.

Good shout on heaters too, if the existing countdown timer isn’t needed that’s cool too, I’ll store it in my box and it’ll find a use eventually

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Sorry, when I said bump switch I meant your boost timer. I thought that was a good idea.

When the original Axminster air filter broke, we initially tried to fix it before we got a new replacement. So we got to see how it was controlled when trying to find the fault. I’m not great at electronics but @Ben_Dooks & @Greg both saw the control board and may be able to remember / advise on how we wire in an automated system

In its normal mode the fan has a timer setting, 1hr, 2hrs & 4hrs which is set by pressing the timer button (2 times for 2hrs, 3 times for 4hrs). If I’m the last person in I’ll often set the fan to run for 4hrs.

I do remember that when I spoke to Axminster to first report the fault (as it was still under warranty) they told me that taking the control board off and bypassing it to power the motor wouldn’t void the warranty, though similar to the fresh air fan I assume the fan has a maximum run time (though I can’t find any info on it)