An eye on the dust

How’s your dust bag?

Mine? I know it is getting full. But there is full, and then there is full.  I’m sure I can fit the sawdust from just one more saw cut in there.  And again, and again.

I have the extractor in the attached shed: saves on noise, saves on the otherwise lost floor area, and any dust leaks (if any) don’t matter.  But it does mean out of sight, out of mind.

I finally got around to changing the collection bag.  What a mission! It was rather fuller than I thought, and it was cumbersome, heavy, and a right pain.  Yes, I know I should have changed it earlier.  Yes, I know I could have checked more often.  Coulda, shoulda, woulda.

A great pile

So.  I need to keep a closer eye on the dust collection.

One thing that’d help is to do a pre-separation.  By placing the pre-separation drum in the main shed, I can keep a better eye on it.  There isn’t the issue with dust escaping from the collector as this is not the end of the line, and the inside of the drum is maintained in a negative pressure.

Rerouting the corner

I had a bit of a win doing the rerouting necessary to fit this drum in.  Got rid of a MDF cabinet, fitted the drum in, and then while trying to think of what to do with the two sanders, I happened to notice the Walko sitting there which I had used at Ballarat and hadn’t gotten onto putting back into the other shed.  Perfect fit!  Sure, a bit cramped (where in my shed isn’t!), but a solution where I wasn’t sure if I’d find one.

Walko is in the house

Getting back to the dust collection, and added an extra feature: an electronic eye to keep a watch on the dust collection, and let me know when things get too full.  This one is pretty cool!  It is the Trupro Dust Sentry from Woodworking Warehouse.  It may seem like some others, but for one very unique, clever feature.  But more on that shortly.

The sensor

The sensor fits very easily – drill a hole.  There are nuts on the threaded sensor that fit either side of the mounting position, holding the sensor in place.  The sensor has a maximum range of 40cm, and that meant it found the other side of my drum.  However on the side there is a small pot, and that can be wound down giving a decreased range.

Mounting position

You could use that sensitivity range so the sensor pointed straight down to where the dust was gathering, building a pile towards the sensor, or you can side mount it (as I have here) so it ‘sees’ the pile when it reaches that height.  I may change this location when I change the lid, but this was a good trial point.  (Lid change discussion at end!)  When the lid is changed, I’m likely to mount the sensor looking down – means I won’t have to remove the sensor each time I wheel the bin out for emptying.

Sensor range

You can test the sensor by waving a hand in front of it.  When it ‘sees’ you, a light comes on at the back (and a signal is sent to the control box).

Control box

The control box has the circuitry inside, and plugs into the wall for power.  It has the audible alarm, and an adjustment dial – all to do with a very special feature of this specific dust sentry….but I’m still not quite ready to tell you what that is!


Mounting the control box is very easy – couple of screws in through the back into a beam.

Dust speed

Ok, ok, the special feature.  This dust sentry is unique (as far as I can tell), as it doesn’t get fooled when a large quantity of heavy dust flies past it.  This sensor can be tuned to ignore passing particles that otherwise give a false reading, and triggers only from the stationary dust – the true level of dust in the bin.  This sensitivity can be tuned to your particular requirement.


So here is the unit all set, ready to sense. Ready to keep an eye on the dust!

Lid change: well, once I got all this set up, it was all working well…..except the pile of dust in the bin didn’t seem to be increasing.  At all.

I did experience this when first playing with this lid a few years ago, and was mucking around with all sorts of combinations of plumbing fittings to create a swirling, pre separation thing.  Really can’t be bothered trying to fix a bad design this time, so am looking at replacing the lid with this one (also from Woodworking Warehouse).  Chalk and cheese on the design!

Jet 2 stage

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