Thread: Looking for ideas

I looked into this a couple of years ago. At the time all alarm-based options were either expensive or unreliable. In the end I fitted a narrow perspex window to the wall of the wooden dust collection bin and an LED MR16 bulb to the top. Obviously this system only works if you have line of sight to the bin.

Easy.

• Rasp Pi Zero2W with a small screen.
• Two air pressure sensors*

One before the inlet and the other inline (before the cyclone). BobL called these "manometres" and used a simple tube with red dye (search the forum)

As the pressure on the internal manometer increases it shows how full/clagged the filter is.

For bag fullness, weight it.

• Use four pressure sensors, one on each corner.
• The bag is placed on a board, then the pressure sensors sandwiched between that board and one below it. It is essentially a scale. One could hack a bathroom scale.... (they employ the same sensors)

OR, one could use a ranging sensor ** which is accurate to a few mm. Mount it externally.

.....

Feed all this data into the Nano and wifi/send a message (sms or other, via the python messaging service) to your phone.

Display all results on the small screen, which could be either eye-catching green or red background if the inputs are within your own parameters,


* Environmental Sensor, Temperature, Humidity, Barometric Pressure on this module, but there are others that also do VOC and a whole heap of other measurements.
** there are other ranging sensor types. I simply chose one that would "see" the amount of dust in the bag and give a distance measurement to where its pointed.


7.3inch-e-paper-f-1.jpgScreenshot 2023-12-02 at 12-30-02 BME280 Environmental Sensor Temperature Humidity Barometric Pr.jpg3.jpg

If it were me i would use a capacitive sensor...

Thanks guys for your ideas, I’ll read and digest what’s been suggested so far and get back to you soon.

is the cyclone dumping into an actual bin or a bag?

honestly the cheapest and most reliable method is to write "go and check dust bin" in big black permanent marker around the start button

Some time ago I was looking at a proposed system that went by weight rather than volume. It appealed to me as I tend to use cheap bags that don't behave nicely when full of green/wet/heavy shavings and/or dust.

Sadly, the site discussing it disappeared shortly thereafter, I don't know why.

But I still like the idea...

Originally Posted by Skew ChiDAMN!!

Some time ago I was looking at a proposed system that went by weight rather than volume.

How does it allow for the huge variation in wood densities?

...and difference in density of sawdust and thicknenser/jointer shavings?

I don't think it was that involved; it was only a proposal that someone was considering developing.

I'd imagine that you filled a bag or two with 'normal' shavings to determine a max weight and just set it to trigger an alert at that weight or a bit less. I don't really care if the bag is only 3/4 full or thereabouts, I'm not that into "industrial economics."

Heavier stuff would fill the bag to a lesser degree before setting the alert. (This is what appeals to me; I've had too many bags with wet shavings split open on removal from the DC, even though they weren't yet fiull.)

Light stuff could be a problem, overfilling the bag if you were relying solely on the alert instead of actually checking as per normal. To me such a device is an aid, not a replacement for looking.

Another part of it that appeals to me is the possible simplicity. No need for pitots to measure wind speed or trying to shine lasers through rains of sawdust. Setting up a digital scale to weight the bag withing reasonable tolerance would be challenging enough for this li'l black duck.

Originally Posted by Skew ChiDAMN!!

To me such a device is an aid, not a replacement for looking.

To me that renders the device redundant. If you need to look to ensure the device is doing its job, you might as well just make it a habit of regularly looking.

Before I went to a cyclone with dust bin, I had a DC with a felt bag on top and poly dust bags on the bottom. The bags I had were very thick. I can't imagine one splitting. Are you reusing them multiple times?

Originally Posted by havabeer69

is the cyclone dumping into an actual bin or a bag?

honestly the cheapest and most reliable method is to write "go and check dust bin" in big black permanent marker around the start button

Thanks havabeer69, I think I’ll follow your advice, at least for now.
BTW, The bin is a cyclone 44 gallon drum, it amazes me how fast it can fill with thicknessser chips.

Originally Posted by Shedguy2020

Thanks havabeer69, I think I’ll follow your advice, at least for now.
BTW, The bin is a cyclone 44 gallon drum, it amazes me how fast it can fill with thicknessser chips.

Running an industrial CNC router with 2440 x 1820 melamine sheets on a busy day we could fill the 44gal drum on the unit within 4 hours, ie 2 drums per shift. How long does the thicky take?

It’s a 500mm wide spiral cut machine at our local shed and it’s probably one of the most used machines their.
It’s fairly regularly filled to its ‘limit’ in a morning, once it’s too full and the cyclone action cannot work anymore then the machine shute will start to block and/or the chips will start going back to the fan unit dust bags.
We were trying to overcome the ‘idiot factor’ it’s taken us long enough to instil the habit of using a metal detector prior to use!