Analog rotation sensing with relay control

Posted by: @fastrunner08

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I'm already writing a book here, and don't want to bore you with the details...

I really appreciate that you did write a book.  I'm a naturally inquisitive person and knowing why something is the way it is... is interesting even if not directly usable.

Posted by: @fastrunner08

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My thoughts are to do this with hall effect sensor for each of the 4 augers, but where I need some help is around how to try, keep the system analog if possible.

This may be more my curiosity than actual need to know... but why do you feel the need to keep it analog if possible?  You're obviously going to get it into the digital world eventually with your choice of using Arduino.

I can think of many ideas with spinning detection, but they're all digital.  

Let me throw this hair-brain, back to fundamentals that "your book" allows me to do versus a simple query of, "how do I detect spinning?"

1. First, do you know how much current your 110V motors draw
   1. Bad - when belt snapped?
   2. Good - when running normally?
   3. Good - when under maximum working load?
   4. Bad - when they're in a bind?
2. If so, is there enough variation between these values to conclusively state it's in that condition and not one of the others?

If so, I might suggest that you use the hall effect sensor for direct current detection instead of a spinning magnet.  I don't have a clue what current levels, and these are all probably way under what you need, so these examples are merely conceptual...

• A hall effect sensor to wrap around wire powering AC motor -  https://amz.run/7I7M
• I'm a big fan of ESP8266 instead of true Arduinos, but it still is compiled using the Arduino IDE.  It has WiFi so you could easily have it notify you of when something is amiss -  https://amz.run/7I7U
• A relay shield that works with that WeMos ESP8266 to cut power to the motor -  https://amz.run/7I7a
• Something to power this rig via the same 110VAC -  https://amz.run/7I7o

That should just about cover the hardware.

@fastrunner08

After a google search on what is a stirator I see the use of a mercury switch to detect a tilt?

@inq @fastrunner08 As a former heavy industrial electrician, I can tell you Dennis (@inq) is bang on. However, I think you are 220VAC, not 110VAC, for the stir motors. Also, could you add the same detector to the rotator 110VAC motor? WiFi may be a problem, so use LORA.

EDIT: YES, thank you for the 'book'.

Posted by: @zander

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As a former heavy industrial electrician, I can tell you Dennis (@inq) is bang on. 

I'm always glad when I'm on the right/same page when it comes to hardware.  Maybe, I'm beginning to learn from you and the other hardware guys.  😊 

Posted by: @zander

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WiFi may be a problem, so use LORA.

Well... yeah.  Even though I'm hip deep in trying LoRa out, I still don't think of it first.  Thanks for reminding me.  @fastrunner08 if this is a new term to you (it was to me until recently) this is @dronebot-workshop YT and thread on it:  https://forum.dronebotworkshop.com/2023-videos/lora-long-range-radio-for-iot-arduino-esp32-rpi-pico/

Hi @fastrunner08,

Just to re-cap what @inq has already specified.. the use of current sensors to monitor the load on the augers is a good idea, but it requires knowing what the different loads might possibly be... ie: stall  amps, running amps normal, and of course, no load amps. this can be quite an ordeal to figure out for someone who isn't fairly proficient in electrical motor application and theory background. But having said all that, the idea of using hall effect sensors to monitor the rotation of the augers  is a good one, but you could also use an encoded as well, so that the pulses can be counted in a time interval, and you would know if the augers have stopped rotating, or slowed down significantly due to binding. This can easily control a relay to shutdown power to the 110 vac and the 230 vac motor systems when required. The environmental problem can be addressed by locating the MPU( micro-processor unit) ie: arduino, to a remote location outside of the grain bin in a weather proof electrical enclosure where the power and sensor signal wires can be run to the sensors on the auger beam, thus isolating the MPU from the high humidity and heat. the electrical enclosure can be fitted with a Thermoelectric cooling ,that uses the Peltier effect.

Just a few thoughts for you to consider.. I think your on the right track.

regards,

LouisR

Posted by: @inst-tech

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this can be quite an ordeal to figure out

I agree... and I'm not sure... but from @fastrunner08's description, there may only be one motor and all 4 augers are belt driven.  If so, that would compound the issue considerably.  But... I just found a picture of what I think he's talking about and it has a motor on each of them.

By using a hall effect sensor, I'm assuming you're meaning to have say a magnet attached to the belt pulley and sensor close to it and see if it passes roughly at the appointed time???

This is a more digital solution, but it is not quite as fidgety about getting a hall sensor / magnet aligned. 

I would suggest just using an infrared to accomplish the same thing, but it would detect the wheel passing.  They look to have spokes so a spoke passing under it would be counted and you'd get a signal / spoke versus one per magnet passing.  Something like this:

https://amz.run/7IA8

Unfortunately, those need to be fairly close, but just detecting a shadow, it might have a range of an inch or so.  If you needed more clearance, you could also use one of these and they might detect stopped motion near instantly versus waiting for a spoke to not pass by.  I've never used these, but I think they have adjustments on them to tune their sensitivity.  

https://amz.run/7IAB

My main point, the entire electronics/sensor package could be made in one unit and sealed.  3D Printed case or equivalent.  And, it wouldn't need any secondary pieces, "magnets".

Posted by: @inst-tech

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The environmental problem can be addressed by locating the MPU( micro-processor unit) ie: arduino, to a remote location outside of the grain bin in a weather proof electrical enclosure

I'm thinking that if these are silos, he may not have a router handy near by even if the MPU is on the outside of the silo.  They may be hundreds of yards away from the nearest one.  

Louis, if you ever had need of such monitoring, you might look at Bill's video on that LoRa.  One of Bill's experiments had the sensor/unit inside a freezer chest in his basement and he was still getting reception multiple suburb blocks away.  I'd have thought a freezer would be durn-near a perfect Faraday cage.  I've got some of the LoRa units coming and will be abusing them for distance, but they're claiming miles... not yards range like WiFi.

VBR,

Inq

Hello. I agree that an analog system might be best here. One method is to incorporate a current sensing relay into each of the four auger motors. These devices clamp around one wire going to the motor and sense the motor current, turning on when the current is above some normal set value. The set current can be adjusted to a level that would reflect a broken belt. Here is one such device.

https://www.supplyhouse.com/Functional-Devices-RIBXGF-Enclosed-Self-Powered-Split-Core-Fixed-Current-Sensor-35-150-Amp-Wire-Leads?utm_source=google_ad&utm_medium=Shopping_tm&utm_campaign=Shopping_TM_New_users&gclid=CjwKCAiA3aeqBhBzEiwAxFiOBg4Rvgm9XeeiJuuPzCoV0FlNonaLqFgUIma5VitcR7HBT2zp75HfMBoCTW0QAvD_BwE

Note that the output switches cannot handle the full power of your 110 volt motor, so you would need a low voltage relay to switch the motor on or off. I did not see a power rating for the 110 volt motor, so be sure the relay can handle the rated horsepower of the 110 volt motor. I suggest a solid state relay rated for the motor current or higher. These are typically turned on by a low voltage DC signal, so you would need to add a small AC to DC adapter, 12 to 24 VDC would be good. Here is one solid state relay available from Mouser, rated for up to 240 volts 30 amps. that may or may not be adequate for your 110 volt motor, depending on horsepower. You can find the AC to DC converter at Mouser or ebay, Amazon, etc.

https://www.mouser.com/ProductDetail/TE-Connectivity-PB/SSRK-240A30?qs=F5EMLAvA7IAyBNXDLKViEw%3D%3D

Connect the four current sensing relay contacts in series and place them in the control relay circuit to switch the low voltage DC on or off. If any one auger motor current drops below the normal set current, the current sensing relay will turn off.

Bob Butcher

retired electrical engineer

@inq My experience with the (white dome) PIR sensors is very poor. The hall effect or an IR beam through a drive wheel if it has openings (or drill one) are all better in my opinion.

@bbutcher85 I think the OP said the auger motors are 220VAC, the motor that moves the auger motors around is 110VAC. In either case their are parts for both 110 and 220.

@inq I'll try to answer all your questions.

Why analog.  I'll start by saying I love digital, i have so many farm improvements that I have made over the years with pi, arduino, and now i have been messing with lattepanda a lot.  In this case, i don't have a super large amount of room on the beam that the sitrator is built on, and so mounting a box to contain all the components ie, 12v or 5v transformer, microcontroller ect will be tough if it is too big of an enclosure. The other big reason is the use environment (dust, moisture, temperature extremes).  In my mind analog might be more reliable. 

I  agree, all my thoughts were around digital as well.  Reliability though is key considering the "tilt switches on it now are crap" I'm worried about the reliability of an Arduino in the environment.  Then again if i made it such that if it failed the relay kept the motor circuit open it might not be too bad, just annoying needing to get a ladder into the bin to get up to the beam to fix it. 

No to the motor load question, I don't know, but i think the track motor is pretty constant as it is geared way way down to move around the track slowly.  (I need to get into the bin to provide pictures and maybe a video.  I didn't have a chance today, since i was out combining).  The one 220v motor that powers the actual stirring augers might see a few different loads, but I think the belts would slip before it gets overloaded.  all 4 augers are belt driven off of it, not direct drive.  The reason the belt broke that caused the auger to stop aka the upset condition was actually because an tensioning idler wheel bearing seized causing the belt to rub/overheat. 

@Ron Yes the motor driving the augers is a 7hp 220v motor.  The motor driving the unit on the track that causes it to travel around the bin is 110v.  I'm going to try and get some photos and a diagram tomorrow while i'm replacing the bad idler pulley. 

@inq & @Ron, yes I have some loRa experience.  I actually configured the hardware/built a GPS system using the ideas/info from OPENAG GPS for tractor guidance earlier this year.  It is super awesome, and i was able to build an Autosteer system for my planting/spraying tractor for about 2K when the equivalent system from a dealer/ag precision planting developer would have cost around 28-35k.  For the GPS RTK correction data I built a base station at my house and used loRa to send the correction data to the unit in the tractor.  I plan to build a few more for my other equipment this winter after i finish harvesting. 

@fastrunner08 I am sure Dennis (@inq) won't mind me answering that first part. The kinds of controllers we are talking about can run on batteries if needed, the case can be fairly small and sealed, so no issues with the environment.

Given what you have already accomplished, I am shocked you are having trouble with this project. Exactly what part is stumping you. You need a sensor to detect one of the stir moptors is acting strange and we have suggested 3 or 4 types. The controller/processor you have done before and used LORA so exactly what is the part you are having trouble with?

I don't see much benefit of monitoring the 110 motor, but it will not hurt to do so.

Concentrate on the sensor to determine there is a problem, the rest is more straightforward.

Hi @fastrunner08,

   Just a comment or two. 140 Fahrenheit is 60 Celsius. Most commercial chips are specified up to 70 Celsius, but that is the silicon inside the package, which will be heated by the electricity it is using, so you are right to be suspicious, but this is a 'soft' wall, that can usually be pushed a bit. One trick is to slow down the clock rate of the processor. As usual, some trial and error testing will be required.

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You might be unlucky and have one or more premature failures or programmes crashing, so assume that will happen when assessing safety precautions.

But many environments with digital electronics are worse than yours appear to be from your description ... be prepared to work a little harder and more intelligently, find out the real issues, and fix them.

Of course, all of the responsibility is yours!!!!

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And maybe you can put the electronics somewhere a little cooler, or even provide a small chamber with cooling air blown down a tube/duct with a small fan?

As for sensing, I would suggest hall effect .. for comparison, petrol engines now often use a hall effect sensor to figure out when to fire the spark .. and that part of the engine must get to the same sort of temperatures. Plus, unlike optical sensing, it is relatively impervious to dust, of which I suspect there will be quite a lot.

I presume you would attach a hall sensor to each auger, and pull the power if any of them stopped sending pulses. You might consider if you are looking for a complete cessation of pulses, or just a relative slowing, which might indicate a belt slipping or similar, which I assume would be a better time to do maintenance, for lots of reasons.

Making an analog circuit that simply spotted no pulses for say  one second (assuming the normal rate was more than 1 per second), should be fairly easy, but a digital system could be much precise and versatile.

Of course, I have only considered low voltage circuits to detect a problem, and I have not discussed the methods of switching the power to the motors. I assume you have, or will get suitable skilled personnel to do that part of the task. Please don't take any unnecessary risks.

Good luck with your project. Best wishes, Dave

@davee @fastrunner08 The case containing the MPU/MCU can be mounted outside the silo where it should be cooler, especially if mounted on the shady side..

To add to my previous post, batteries are possible, but if 110 or 220 is available, then a simple phone charger-type wall wart can power the circuit.

@fastrunner08,

Posted by: @davee

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Plus, unlike optical sensing, it is relatively impervious to dust, of which I suspect there will be quite a lot.

Totally agree, now that I hear the conditions.  Can't say I've ever found myself inside a silo... yet.  😆   

Temperature - @davee is unconditionally one of the hardware guys.  But, the ESP8266 I specified above is rated -55ºC to +125ºC.  I've made several projects that I've 3D Printed ABS Housings for.  I even totally sealed them (melted ABS plastic) so that they can be under water.  

Size - the components I specified would all fit in about 3 cu-in although the relay is way too small.  It'll only handle 10A @ 250VAC.

One last try on a digital, single unit design... (hey, I got'a try)  I'm enamored to the single piece designs.  Having secondary parts, magnets, senders/receivers that have to be placed securely / accurately is a PITA.  How about the radar units?  I have a couple, but haven't played with them yet.  I was disappointed to learn (after getting them) they don't give position/distance, just that things moved.  These with the Arduino could be sealed inside a housing and the radar just shoot through said plastic.  If you don't have a 3D printer, you could use epoxy.  Just a thought.   

https://amz.run/7IIw

Anyway, sounds like a interesting project.  And also... if you want to share some of your others, I'm sure many of us would be interested in seeing some of your solutions.

VBR,

Inq