A problem with a motion detector.

[waross]

I need help on this one.
I have a no-name motion detector at a remote site.
The owner tells me that it is acting erratically.
What I have been told, I can't vouch for the accuracy of the statements. (That may be part of my problem)
This is a cattle watering system.
The motion detector is the second new detector.
When the detector sees motion, it starts a submersible pump which fills a watering trough.
The cows tend to come together at different times of the day, and when the detector sees the cows it turns the pump on. It times out about 90 seconds after the last detected motion.
It doesn't always turn on.
It may turn on and run continually.
I had the owner cut all the tall weeds and grass away that may have been giving false signals.
The supplier is very protective of his sources and will not supply any technical information.
On a phone call he verified that the detector was correct for the supply, 24 Volts DC, and that the output was relay contacts, not an electronic switch.

Possible causes, you tell me: The watering tub is supported by a rough textured black plastic culvert, about 36 inches in diameter. Could bright sunlight on the plastic be causing issues?
The detector is facing north and looking at the south side of the culvert.

The detector provides a signal to an inverter which drives the submersible pump. I will check if the inverter is hanging on.
Wiring. The next time on site I will look at the possibility of rewiring the installation. We may have some compromised wiring.
(Bad insulation and high leakage.)
I am open to suggestions as to replacing the unit.
24 VDC supply.
Relay output, able to switch 120 VAC.
Able to work at minus 40 degrees Celsius or colder.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[3DDave]

I assume an optical/PIR detector and not a microwave one? I have a PIR one that often refuses to detect ME and wish I'd gone with a microwave sensor. I can wave, walk back and forth. Painful. The microwave ones are used for security and I've found them to be most amusing in trying to hold still long enough for them to time out. Not easy. I see that microwave sensors may be too sensitive, but they should be adjustable and, well, it's cows, so that helps.

 

[itsmoked]

That's a tough one. I'm not even clear on the style of detection. A standard motion detect will have lots of problems with daylight detections.


What's the power source, battery solar?

To solve this I think you need to be a cow. A patient cow.. I can see the system blinding itself after a completed motion cycle. Then staying blinded as cows mill around continuously after that.

If it's solar you should check the battery voltage. Could be it's marginal. Could be the voltage dips and resets the sensor.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[MacGyverS2000]

"Motion detection", to me, indicates some form of optical recognition... I doubt the cost for such a detector was put into this, so I have to assume a simple sensor (e.g., PIR).

I'd start by completely covering the sensor for a day and see if the pump still turns on/off. If it does, you're not dealing with a sensor issue, you're dealing with a glitchy electrical issue (switch, power noise, etc.). If the pump never turns on, on to stage 2 of debugging. Place a short pipe over the sensor with black construction paper inside... that will narrow the field of view a bit and cut down on incident light being reflected to the sensor... again, leave it for a day and see if the pump is triggered.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[waross]

Thanks friends.
Battery voltage: This is the setup with the Primus Air 30 wind turbine as well as solar. The Turbine locks down and stops turning at 27 Volts on a 24 Volt system.
The turbine is typically stationary (eg: 27 Volts) until the pump starts,)
One description that I found as to the operation of a PIR seemed to indicate that they responded to temperature differences to infer motion.
The vertical, flat black culvert section may be heated above ambient temperature on a cold, clear, sunny day.
I wonder if that may be an issue?
I am going to town today and am considering buying a couple of rattle-cans of flat white paint and painting the culvert white.
Any comments?
The cows need water every day, preferably at their choice of time. They are grazing over several square miles. It seems as if one cow gets thirsty and heads for the water. Herd instinct kicks in and the rest follow.
There may be serious consequences to a failure to supply water.
The cows tend to then look for water in the dug-out, the summer water supply.
Even though the ice may be several inches thick, the combined weight of a herd of cattle may break the ice.
In the last week or so, a local rancher lost about $50,000 worth of cattle when the ice broke and they drowned in his dug-out.
This is not a trivial problem.
Thanks again.

Then staying blinded as cows mill around continuously after that.

That is not a problem. That is normal operation. The issue is; the pump continues pumping after the cows have left.
Over pumping and overflow leads to two serious issues.
1. The water must no make its way back down the well casing. The environmental branch will not allow anything to be introduced back into the aquifer. The overflow may contain cow slobber.
2. Damage due to surface overflow. After the last serious overflow issue the earth around the vertical culvert section was partly softened and partly washed away and the culvert tilted to one side.
The eye was replaced after that wreck.
They brought in a vac' truck to excavate around and straighten it up.
After that there are no weeds or grass left to give a false signal.
I just spoke to the rancher.
The water bowl has cracked badly. It is losing a lot of water.
The cattle are there for extended periods, but it doesn't seem to be running on after the cows leave. The run on issue may have been a fault in the previous motion detector.
The culvert is no longer flat black. The sides are now covered with frozen water and cow slobber. That is probably masking it better than a paint job would.
I now understand that when the eye fails, recycling the inverter that drives the pump will restart it.
Disclaimer. All information may be suspect. These people raise cattle and do it very well. However they may be misled by electrical symptoms.
Moving forward: I will be looking at the wiring and the inverter.
Speculation:
The inverter may be drawing the batteries down and cycling off on low voltage. By the time the rancher checks it, the batteries will have been recharged and cycling the control switch off and on the inverter would restart.
The next time out, I will be trying hard to identify the motion detector and the inverter so as to get technical specs from the makers.
The story on this comes out bit by bit.
I enjoy working with these folk, but it does bring out the human aspect of trouble-shooting.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[waross]

The tall grass and weeds have been cleared away.

Looking easterly. The fence is running east and west.The galvanized culvert was a previous installation. This was a wet well that was connected to the dug-out in the background by a pipe, buried below the frost line.
An excavator was cleaning the digout and inadvertently "cleaned" the buried pipe.

Looking west.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[3DDave]

Big Clive has a good video on PIR:

https://www.youtube.com/watch?v=evZM2_RTvTU

Also of interest:

https://www.youtube.com/watch?v=cL4h2gNFJeY

and

https://www.youtube.com/watch?v=Hf19hc9PtcE

 

[waross]

Thanks Dave³

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[LionelHutz]

I'm using cameras and detecting people or cars at the new house, but that's way too complicated for there.

Putting a shield around the motion sensor might be a good idea.

Using RE it needs a low voltage cutout that will reset itself when batteries are charged enough again. That needs to be added if it's not there.

What about using a DC pump? Get rid or the power conversion.

 

[itsmoked]

Those pictures helped (me) immensely, except where is the sensor?

Is this cockamamie setup to keep the watering bin from freezing?

Does the water all go away in a few minutes? If so where does it go that doesn't cause muck problems? Back to the pond?

If this is the point then: the bin is empty.
The cows walk up and signal their presence.
The pump starts and runs filing the bin to some overflow.
The overflow goes back to the pond(?)
Cows drink
The cows split the scene.
The water ALL drains back to the pond.
The system waits for more cows.

Correct?


Beware small animals coming for water. I put up PIR sensors at the train yard and small animals set them off continually; opossums, cats, skunks, coyotes.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[Comcokid]

Flock of birds? Occasional hawk? Varmints? Some of these are smart enough to learn how to turn-on your water fountain. Again, like itsmoked asked, where is the PIR sensor? A mouse at 6 inches probably looks like a cow.

 

[3DDave]

It's not required to identify things with a camera, just enough to detect that some number of pixels in one image are very different than those in another. To keep from picking up waving grass, do the difference and then expand/contract the delta by one or two pixels. This will take out the majority of little stuff; then count the number of pixels that did change.

There was a script to do that sort of detection with the CHDK (Canon Hackers Development Kit) that ran on Canon small cameras. It could send out a signal via a status LED if there was enough change.

It's still amazing to me that a person can now buy billions of transistors for not much money and build devices that were science fiction dreams in the 1960s to do tasks like read the numbers on gas meters using OCR, transmit the results over a reliable radio connection, and operate it with software that is mostly copied from free sources. The toughest part is getting reliable power.

 

[waross]

If this is the point then: the bin is empty.
The cows walk up and signal their presence.
The pump starts and runs filing the bin to some overflow.

Spoiler

The overflow goes back to the pond(?)

Cows drink
The cows split the scene.

Spoiler

The water ALL drains back to the pond.

The system waits for more cows.

Pretty close.
The pump starts and runs filing the bin to some overflow.
It doesn't generally overflow. The cows drink a lot.

I will try to check out small animals and birds.
The first motion detector was damaged by birds.

DC pump.That will be considered. The original pump was DC.

For now, I will be investigating the small animal/birds possibility and the low voltage possibility.
All suggestions have been helpful. Thanks.

In the last picture, the motion detector is mounted about 6 feet high on the furthest vertical post,pointing to the right.



--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[itsmoked]

A PIR sensor is filtered to only see fast changes in the scene. That way ambient changes like the sunlight don't trigger it. Anything faster than a second or two will trigger them. Mounting the sensor up a spindly pole that is subject to any wiggling by the wind can trigger them because they see changes in the horizon faster than a few seconds. If it can see the water column that could confuse it too since it would be a sudden thermal change in the scene.

I'd make sure it was on a rigid pole like a 4x4 or pipe driven in the ground.

You also wouldn't want it to 'see' the sun anywhere in the sky as that can swamp it causing no triggering.

Some have ridiculous viewing angles that can be problematic too.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

It is on a substantial pipe driven into the ground. I will check for rigidity.
It is pointing north.
It doesn't see the water (until it is already in trouble) Something has to hold the pump on for five minutes or more before the water is high enough to be seen by the eye.
I will be particularly paying attention to birds and low voltage.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!