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Robert Walters
10-14-2010, 1:04 PM
I'm building an air scrubber and would like to incorporate an air flow or air pressure switch of some sort.

1) Has anyone played with car air sensors before, or maybe come across one that doesn't have a funky connector that could be used for this application?

I seriously doubt most car sensors are meant to be used on a dust collector though.


2) How would you install one in such a way that that it can detect a reasonable airflow or pressure going though it? The only thing I could think of is install the sensor in a small tube, and place the tube in-line with duct work.

I'd prefer air pressure as then I could tell if there has been some change or blockage down the road.

Rodne Gold
10-14-2010, 1:15 PM
You could easily rig up a MAF (mass air flow) sensor or a MAP sensor (manifold absolute pressure) to some sort of alarm system , albeit I wouldnt bother , you can rig a simple mechanical pressure relief valve with a whistle even cheaper

Robert Walters
10-14-2010, 1:29 PM
You could easily rig up a MAF (mass air flow) sensor or a MAP sensor (manifold absolute pressure) to some sort of alarm system , albeit I wouldnt bother , you can rig a simple mechanical pressure relief valve with a whistle even cheaper

Hey Rodney,

Do you think a MAF/MAP sensor could deal with the airflow of a dust collector without saturating it?


I'm up to no good here...

Once in a while I'll forget to hit the exhaust until after I hit the START button. So I'm working on a way to start the exhaust automagically but requires "feedback" that the air is flowing.

I'm also adding in an OFF-DELAY timer (~20s) to exhaust the chamber once the job is complete.

Rodne Gold
10-14-2010, 3:11 PM
Well the MAF sensor would heat a wire and the airflow would cool it and drop the resistance , depending on what you use , it could cope with 1000cfm - any air flow would drop the resistance actually. You could use one from an old V8.

You could also use an adjustable hobbes switch which is a pressure sensing switch - used to use one on my NOS system, if oil or fuel pressure dropped it switched the system off.

Would probably be easier to take a T off a power feed somewhere on the laser which is powered when you hit start to switch a relay to turn on the blower.
In the car world , you can get programmeable boost sensors - will monitor boost and switch various systems like a dump valve at predetermined levels.

Im not quite sure what you want to do , start the blower on start - monitor to see there is air flow and then also monitor the pressure to see if there is a blockage?

George D Gabert
10-14-2010, 3:12 PM
Just a thought

Put a limit switch on your outlet flapper. When no flow the flapper is against the switch, when there is flow the flapper moves away.

GDG