# DIY Dust Sensor Build Help



## Rayne (Mar 9, 2014)

Calling all LJ hive mind with a knack for electronics. I have been researching a way to create a cheap Dust Sensor bin similar to that of a popular device. I have the recommended parts, but not entirely sure how to wire all of this together. That's where I would like LJ's to come in and see what can be done to make this work. I researched the photosensor and found a very similar item (if not exact) to the one used in commercial businesses. I also found a review that listed the exact part I found, so that was reassuring. I'd appreciate any feedback into putting this together and would love to build this, post the build, and let anyone else have at making one themselves. What do you say? If you have any other parts to add, by all means, let's see if we can make something as a community that could help all of us.

Parts: 
1 - Banner QS18VP6D Sensor (there's also QS18VN6D that seems to be more readily available, but I honestly don't know the difference)
1 - 12V Strobe light
1 - 12V DC / 200mA power supply.


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## TheFridge (May 1, 2014)

The concept would work. Don't know about those particular parts. I'd worry about dust build up on the emitter and receiver. If it was negligible it could work well.

I'd add some kind of off delay of about 10 secs.

I think that is the wrong sensor for what you're trying to do.


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## Redoak49 (Dec 15, 2012)

I believe there were several thread on this over on the Creek(Sawmillcreek).


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## Rayne (Mar 9, 2014)

> I believe there were several thread on this over on the Creek(Sawmillcreek).
> 
> - Redoak49


Kind of weird that none of the sawmillcreek posts showed up when I searched for the threads until I typed in "sawmillcreek" as part of the keywords. A whole slew of posts popped up and there is indeed one that had all the information, like verbatim and pictures on how to make one. So very simple; even pointing out the differences between the PNP and NPN outputs. Thanks for pointing that out and now, I will go out and get the parts to make my own. This should be fun.


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## becikeja (Sep 12, 2010)

Don't believe I would use a photo sensor, I would suggest a capacitive proximity sensor.


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## Mike_D_S (May 3, 2012)

I did the design here: http://www.clearvuecyclones.com/forum/forum/clearvue-cyclones/general-to-be-organized/419-dust-bin-quantity-sensor

The only difference is I used a small LED bulb instead of a candelabra. The parts I got off of Amazon for about $40.

It's easy to build and pretty reliable. In my case, my bin is closely coupled to the bottom of the cyclone (SDD), so I ran the system for a bit to see if the dust had a preferred side it stacked up on, then I mounted the light on the side of the bin and the electric eye on the lid above the light. I used a small household extension cord to make up a disconnect by cutting it in half and then wiring the cut ends to the light and to the relay. The plug ends serve as the disconnect for when I need to dump the bin.

Mike


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## Rayne (Mar 9, 2014)

Just completed my build after getting the right parts. Looks like it'll work perfectly. It cost me about $40. Replacement parts are easier to find as this particular Banner sensor is more widely available. Going to integrate it into my DC hopefully tomorrow.


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## Redoak49 (Dec 15, 2012)

Good work! Could you post links for the parts. I am pretty electronically illiterate but want to build one.


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## EEngineer (Jul 4, 2008)

I design industrial sensors for a living. I have even worked on systems for dust collection. There are few problems with this approach…

The biggest one has already been mentioned - photosensors don't work well with sawdust because of dust buildup on the face. I am familiar with those Banner sensors. The company I work for makes a (very) similar line. They include a plastic filter on the face of them that collects fine sawdust due to static. You'll be constantly cleaning it due to false trips. The other problem is false trips while the dust collection is working - the sawdust tends to swirl around while dust collection is running and may block the light enough to cause false trips while running. You may be able to adjust the sensitivity enough to cure either of these problems but in my experience it is very touchy.

May I suggest a capacitive sensor instead? In real world applications, capacitive sensors have proven to be more reliable than photosensors in sawdust detection. I have been experimenting with a capacitive sensor for my dust collection. It is really hodged up right now because I am still experimenting with it so there is nothing I would post as a project.

I have had good success with two approaches for the capacitive sensor:
1. I hung the sensor from the top of the dust collection canister on its cable. It hangs down to a specific heght and trips as the sawdust covers the sensor face. The sensitivity of the sensor can be adjusted so that a light covering of fine dust on the sensor head will NOT trip it but being immersed in sawdust WILL trip it.
2. The approach I think I will use, though, actually senses the sawdust level through the side of the dust collection canister. I am using a cardboard canister (I think it was used to ship soap powder originally) and I can adjust the sensitivity of the capacitive sensor so that it ignores the cardboard wall but will trip if the sawdust builds up inside the canister above the face of the sensor. This approach should work with a plastic container or almost any non-conducting material but NOT a a metal canister.

BTW, the difference between the two Banner models you mentioned (QS18VP6D vs QS18VN6D) is only the output configuration:
1. the "P" variant has a PNP output - i.e. the ouput pulls up to the + supply when tripped
2. the "N" variant has a NPN output - i.e. the output pulls down to the - supply when tripped


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## Mike_D_S (May 3, 2012)

Is there a particular sensor you are using. I see quite a few just skimming Amazon that seem to be rated for multiple materials and with input voltages suitable for 12v or 120v layouts.

This would be interesting to me to try out in parallel with the optical sensor I'm using now.

Mike


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## Rayne (Mar 9, 2014)

> Good work! Could you post links for the parts. I am pretty electronically illiterate but want to build one.
> 
> - Redoak49


Go to Sawmillcreek and look for "Building your own and improving upon the Oneida dust sentry bin level sensor". It's only fair they get the credit and view for this. The links are posted there along with the wiring diagram.

But if the Banner sensor is not as good as other posters have said, maybe it needs to be slightly updated. I'm not sure. I'm going try to get mine installed this weekend. I'm doing another major MOD on my DC while adding this sensor and a pressure relief valve.


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## Rayne (Mar 9, 2014)

> I design industrial sensors for a living. I have even worked on systems for dust collection. There are few problems with this approach…
> 
> The biggest one has already been mentioned - photosensors don t work well with sawdust because of dust buildup on the face. I am familiar with those Banner sensors. The company I work for makes a (very) similar line. They include a plastic filter on the face of them that collects fine sawdust due to static. You ll be constantly cleaning it due to false trips. The other problem is false trips while the dust collection is working - the sawdust tends to swirl around while dust collection is running and may block the light enough to cause false trips while running. You may be able to adjust the sensitivity enough to cure either of these problems but in my experience it is very touchy.
> 
> ...


Glad to have an expert chime in here. I'm no expert or even amateur by any means. lol. I'm just following what I found, but have read in other places the Photoelectric probably isn't the best as you confirmed. I haven't done any research on capacitive sensor and how easy it would be to rewire it if the phototelectric sensor fails, but like I said in my original post, this would be a good reference in the future for all of us if we all get one working with optimal performance. Thanks for helping out and let us know how yours turns out in the end.


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## Rayne (Mar 9, 2014)

> Is there a particular sensor you are using. I see quite a few just skimming Amazon that seem to be rated for multiple materials and with input voltages suitable for 12v or 120v layouts.
> 
> This would be interesting to me to try out in parallel with the optical sensor I m using now.
> 
> ...


Not sure who you're referencing, but I'm using the Banner QS18VN6D sensor and used the correct wiring diagram for the N output model from the Sawmill creek post reference above.


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## Mike_D_S (May 3, 2012)

Sorry, should have been more specific. I'd like to know which capacitive sensor EEngineer was using in his testing.

Mike


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## EEngineer (Jul 4, 2008)

It shouldn't be a big deal to substitute a different sensor. They are all wired the same way:

BRN= +V (positive rail)
BLU = -V (negative rail)
BLK = sensor output

Like I said before, if it is a PNP output, it will pull up to the positive rail. If it is a NPN output , it will pull down towards the negative rail. It doesn't matter whether it is a photo or a capacitrive sensor, they all have he same interface.

The specific sensor I am using for my tests are no longer made (that's why I have them - they were being thrown out) but they are quite similar to this:
TOOGOO DC 6-36V 300mA NO 3-wire Capacitance Proximity PNP Switch Sensor Detector 1-25mm
(search on amazon)

I used a 24VDC DIN rail supply and a simple LED to show whwn canister is full.


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## Mike_D_S (May 3, 2012)

> The specific sensor I am using for my tests are no longer made (that s why I have them - they were being thrown out) but they are quite similar to this:
> TOOGOO DC 6-36V 300mA NO 3-wire Capacitance Proximity PNP Switch Sensor Detector 1-25mm
> (search on amazon)
> 
> - EEngineer


I didn't do a lot of research, but how focused is the sensing area of this type of sensor. I would assume that since they are commonly mounted perpendicular to the material to be sensed, leading me to think they would have a focused sensitive region out the end of the sensor.

But that would mean that mounting it to the side of a dust bin drum would have the sensor sticking out a bit and potentially being well positioned to get caught on something when moving the drum around.

Would they have much sensitivity to the sides so it could potentially be mounted more or less banded to the side of the drum?

Mike


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## EEngineer (Jul 4, 2008)

You are right. The most sensitive area is at the front face. There is an area of sensitivity to the sides - it is not a "cone", it is more like a "light-bulb" that extends from the face of the unit. So the side-lobes of the sensing envelope might be enough to detect sawdust level. Haven't tried that.

For that reason the first approach for mounting the sensor that I mentioned is more ergonomic. Hanging from the lid of the sawdust container and mounted right next to the dust cyclone, it would stay with them when I disconnected the canister to empty it. My experiments with the second approach center around seeing if I can get enough range to leave the sensor mounted to the frame of the dust collector so I don't have to disconnect it when I empty the canister. What I have right now (still playing) is too finicky about its placement in relation to the side of the container - I only have a 15 mm sensing range and that is barely enough to reach through the wall. With 25 mm sensing range that might get easier.

I am using these just because they were free - I rescued them from the trash. If you are starting from scratch and intend to order sensors, try something like this:
search Ebay for: NEW Omron E2K-F10MC1 Flat Proximity Switch Sensor, DC 3-Wire Model

Note that the flat-packs generally have less range, though. That's problematic with thick canister walls.

Hmm, I thought about those flat-packs more. What if you cut a hole in the side of the canister at the depth you want to fill to and then caulked the sensor into the side of the sawdust canister? It eliminates sensing range problems but would require disconnecting the wiring to empty. I would still like to avoid that.


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## torus (Apr 8, 2017)

@EEngineer

What do you think about "Ultrasonic Distance Sensor". Will they have the same problem as photosensor?


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## EEngineer (Jul 4, 2008)

I spent a lot of time with ultrasonics, too. One problem with ultrasonics is secondary reflections off the walls of the canister. Success in ultrasonic level sensing applications in tanks depends a lot on the geometry of the enclosed space it is used in. In general, unless it is spaced so that the walls are a lot further away than the distance you want to use as a trip level, it won't work reliably. Additionally, sawdust is a very "soft" target (i.e. absorptive) so returns from the sawdust level are weak, usually much weaker than the returns you get from the walls of the container. Most level sensing with ultrasonics is done on liquids or solids ("hard" targets) and in tanks that have large diameters compared to their height - all of which is just about exactly the opposite of what you see in dust collectors.


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## Rayne (Mar 9, 2014)

It's been a long while, but I wanted to update that I finally completed for my 3rd DC Modification. The DIY Dust Bin Sensor is installed and working. I haven't filled the bin yet, but I have put my hand underneath it to test.


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## Notw (Aug 7, 2013)

Rayne, mind listing your final selection of parts you used and how it is wired up?


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## Rayne (Mar 9, 2014)

> Rayne, mind listing your final selection of parts you used and how it is wired up?
> 
> - Notw


Some of the parts are from eBay, so just look it up and match the model number exactly. 
Sensor is from eBay: Banner QS18VN6D sensor
Red Light from Amazon: Huoshang RED LED 12 Volt Security Alarm Strobe Light
Power adapter from Amazon: LE DC 12V 2A Power Supply Adapter, AC 100-240V to DC 12V Transformers, Switching Power Supply for 12V 3528/5050 LED Strip Lights, 24W Max, 12 Volt 2 Amp Power Adaptor, 2.1mm X 5.5mm US Plug

Wiring diagram for the N output from Sawmillcreek's post I mentioned in a previous post above. Didn't want to post someone else's work.


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## Sparks500 (Jun 30, 2017)

Not to derail the topic too much, but, the inside of a a dust bin is a pretty dirty place, and sensors will be tricked or clogged or damaged or whatever.
I'm thinking load cells to measure the weight of the bin. set them for about 40-50lbs, since I don't want to wrestle anything heavier than that to take it out. clean, simple, and not fighting the tornado inside the bin.
Thoughts?


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## Rayne (Mar 9, 2014)

> Not to derail the topic too much, but, the inside of a a dust bin is a pretty dirty place, and sensors will be tricked or clogged or damaged or whatever.
> I m thinking load cells to measure the weight of the bin. set them for about 40-50lbs, since I don t want to wrestle anything heavier than that to take it out. clean, simple, and not fighting the tornado inside the bin.
> Thoughts?
> 
> - Sparks500


Oneida uses the same sensor and I haven't heard of any one having issues with it causing a false positive due to dust build up (mind you, I haven't searched for people having problems; only seen people saying it works). My install has the sensor recessed a good ways in the lid, so debris will have a hard time hitting it, but there could be dust build-up. Even if there is, it's not hard to clean as it's super simple to just raise the lid and roll the dust bin away to get to it.

As for the load cells, I had to look it up but it does look like a decent alternative solution, but you would have to come up with a unique way to separate the load cell from the dust bin for easy cleaning; there is always the harder/heavier way of course.


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## Sparks500 (Jun 30, 2017)

I'd probably put the cells between two pieces of plywood under the bin, making a stand the the bin would just sit on.


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