DIY Temperature Monitor Keeping Cables Straight

1327 Views 15 Replies 6 Participants Last post by BTO Fama, 5 mo ago

physicsuofraui

Discussion Starter · 6 mo ago

I have been working on monitoring grain temperature using the Arduino MKR family and DS18B20 sensors, and it worked well the first year but this year the cables I made got drawn over to one side and now it does not give an accurate reading.

I am guessing this is because it is too far to the side that the grain is not insulating enough to keep a steady reading.

What would be the best way to keep them straight?

Extra Information:
I have a Hackaday page for this project here: Bin Temperature Monitoring System.

I initially was going to post on this thread, DYI Open Source Arduino bin temp reader project **help**, to share my project and trouble, but the system told me it was an old thread and perhaps I should make a new one.

I'm planning to keep developing this project to the point where one could simply buy a unit, climb to the top of the bin, drop the cable down, stick the controller to the bin (probably being held with a magnet), and then scan a QR code with an app, and be able to monitor the temperature in their bin. I also plan to keep this project completely open source, and probably keep a DIY version with an Arduino an option. All, that is to say, is if anyone is interested in a collaboration that would be great too

.

Now I'm going to go browse this forum. Seems like there is tons of interesting stuff!

Reactions: 1

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torriem

· #2 · 6 mo ago

Are your cables just hanging freely, or do you fix them to the floor? All our cables are tied to the floor. And they need to be quite strong tor resist the pull of the grain. The commercial temp cables are made using a steel cable core. Although they recommend using more, we just use one cable per 5000 bu bin, just off to the side of the very center of the bin.

I like the idea of using the Arduino to monitor temps! A few guys on this forum have done something similar. I've never found it economical to make the cables, though. And any new installations we do are temperature and humidity cables for tracking grain moisture as well.

Someone's working on a homemade moisture cable on this forum right now. See Sensors used in OPI's moisture cables?

Guy1000

· #3 · 6 mo ago

You are definitely going to have to tie the cables down. It needs a ridged mount on the bottom to prevent them from being pulled up and to the side when filling.

i am also currently using an arduino to read the cables. I plan on having a “node” that can read multiple cables that the sends the readings with a Lora radio. In theory I should be able to get up to 16 km of range, maybe further if I used a yagi but I haven’t tested it. This is received by a base esp and is stored on the onboard flash memory for logging. This esp also hosts a website that allows you to see what temps you currently have, in theory I want it to be a complete plug and play very similar to what you are trying for but their is still a ton of little kinks to work out.

physicsuofraui

Discussion Starter · #4 · 6 mo ago

torriem said:
Are your cables just hanging freely, or do you fix them to the floor? All our cables are tied to the floor. And they need to be quite strong tor resist the pull of the grain. The commercial temp cables are made using a steel cable core. Although they recommend using more, we just use one cable per 5000 bu bin, just off to the side of the very center of the bin.

I like the idea of using the Arduino to monitor temps! A few guys on this forum have done something similar. I've never found it economical to make the cables, though. And any new installations we do are temperature and humidity cables for tracking grain moisture as well.

Someone's working on a homemade moisture cable on this forum right now. See Sensors used in OPI's moisture cables?

I am not currently tying them down. The cables are currently made out of just 4 wire fire alarm cable, so I am guessing that I will need to upgrade them if I go to tie them down. Last year I think we just got lucky that they went reasonably down straight.

All I am planning is one cable per 5000bu bin and placed about how you described. Currently, I have them space 7ft apart (I think) and there are three sensors in total. I may increase the sensor amount since it looks like the commercially available ones have more.

I am guessing that it would be more economical to just buy cables and then read the temperature from them, but I am hoping to have a fully open-source version. I'll check out that other thread.

Thanks!

physicsuofraui

Discussion Starter · #5 · 6 mo ago

Guy1000 said:
You are definitely going to have to tie the cables down. It needs a ridged mount on the bottom to prevent them from being pulled up and to the side when filling.

i am also currently using an arduino to read the cables. I plan on having a “node” that can read multiple cables that the sends the readings with a Lora radio. In theory I should be able to get up to 16 km of range, maybe further if I used a yagi but I haven’t tested it. This is received by a base esp and is stored on the onboard flash memory for logging. This esp also hosts a website that allows you to see what temps you currently have, in theory I want it to be a complete plug and play very similar to what you are trying for but their is still a ton of little kinks to work out.

That sounds really cool. If I understand correctly your system wouldn't require any outside servers and would act sort of like how networked security cameras work (DVR acts as a server and then you can access it through their app remotely, but don't have to pay for a subscription)?

What are you using for your cables?

Guy1000

· #6 · 6 mo ago

physicsuofraui said:
That sounds really cool. If I understand correctly your system wouldn't require any outside servers and would act sort of like how networked security cameras work (DVR acts as a server and then you can access it through their app remotely, but don't have to pay for a subscription)?

What are you using for your cables?

That is pretty much how I have it planned to work. No servers or anything external from the base. In theory a esp32 comes with up to 32mb of flash with about 100000 write cycles and each reading of up to 255 cables with up to ~15 sensors each works out to about 30kb I should get approximately 10 million writes.

For cables I am currently using the existing opi cables we have. I have tried building some using pex pipe but it wasn’t nearly strong enough to be any good. m_elias suggested pex-al-pex instead but I haven’t had a chance to try it. I am going to try and build a cable stretcher this winter to try and test some of my ideas before I put anything in bin. I am also currently trying to build moisture cables but I still haven’t figured out the sensor they are using. If you are planning to sell a diy moisture cable you should be aware that their is a patent held by opi. It specifies a 3 wire cable that has 2 holes to allow air to flow by the sensor. Might cause problems if you ever got caught selling them.

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torriem

· #7 · 6 mo ago

Yeah grain has a lot of force. I'm surprised it didn't rip your alarm cables down. But I'm glad you're exploring all this. It's really fun. I heard of one person that put the sensors in a steel pipe. But with something that permanent wouldn't work for sweeps. But in a hopper bit it might work. Would need a way of making sure the sensors have good contact with the pipe, or stick through the pipe into the grain somehow.

Surely the Opi patent has expired by now. There are several companies all selling compatible cables. The latest ones I've bought from BinSesse are compatible with the opi reader, even the moisture cables. Of course they could be licensed. The nice thing about patents is they are supposed to describe how it's done, so maybe the Opi patents would list the sensors they use and the arrangement. But IP is abused heavily these days, so maybe they got a patent on the idea, no the actual implementation.

If I was to roll my own cables and reader, I'd ditch the two wire arrangement and go for the full three wires. Much more reliable when you can power it directly, rather than rely on parasitic power.

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Guy1000

· #8 · 6 mo ago

Apparently the patent was filed in 2018. I don’t know much about patent law so I can’t really comment on what exactly this means. But it looks like this one guy has a couple different ones. Erron Leafloor Inventions, Patents and Patent Applications - Justia Patents Search

712alberta

· #9 · 6 mo ago

About half of our bins are secured to the floor with a hinged eyelet, kind of like a light duty d ring. The rest of the bins have the removable above floor aeration and the floor is right where I would want to secure the cable. And if what you attach to the floor has any type of a lip on it, and the floor moves against it when your cleaning the bin bottom that one piece can be a real pain in the arse to remove. So on those bins I use a foot long piece of 2 x 8 with an eye bolt threw the middle . I make the rope long enough for it to sit on the floor. Placement is key using this method. Looking down from the top of the bin, I want the rope to have enough slack so that the cable hangs down straight, or perhaps just a little to the center. When I look down from the top, on our bins, I see the cross of the aeration close to dead center. I place the anchor board so that the cable and rope crosses the center of the bin. This way, as the grain comes in, it covers the board. If the board is going to get moved by the grain, it will only pull the cable closer to the center of the bin. If you run it straight up and down, the board can catch the flow of the grain and ride out to the side. I hope that makes sense.

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physicsuofraui

Discussion Starter · #10 · 6 mo ago

I think it is generally quite hard to enforce patents. I've seen a few patents after doing some googling today dealing with monitoring grain bins. I think unless you are doing something that can only be done one way there is not really any way of stopping people from doing the same thing a different way. I am guessing each company's cables monitor the temperature/moisture differently and that OPI only has a patent on the way that they monitor them.

That's one of the reasons I've tried to steer away from looking at/reverse engineering commercially available cables. I don't really want them accusing me of anything.

I might take a closer look at the different patents to ensure I don't step on any toes.

torriem

· #11 · 6 mo ago

Near as I can tell they are all using the exact same Dallas Semiconductor 1-wire chips. Same 1-wire protocol (which is itself patented and sensors are available only available through Dallas Semiconductor). There are only so many ways to talk to a cable with DS 1-wire sensors on it (2 wires parasitic power or 3 wires with normal power).

torriem

· #12 · 6 mo ago

I took a look at the 2018 patent application (both patents in the search appear to actually be the same). The entire patent seems to surround the idea of using a particular user interface (phone-based) to tell their system where a cable is in a bin and which cables to use with what bins. I'm very surprised this was deemed to be a valid patent. There's nothing original or novel here... Just describing their user interface. Man patents have really gotten absurd these days. You can safely skip that patent, and in fact would be better off for it so you won't be influenced by their user interface design.

In my mind the real novel stuff that's worth patenting is manufacturing techniques for making the cables (including sensor placement and the materials used to encapsulate everything), and any techniques used by the software to create 3D heat maps, track the drying front, and make predictive prescriptions for running fans, based on temperature and relative humidity differences between the grain and the outside air. In many cases patenting is as important as publishing (establishing prior art) to head off big companies steeling your idea and patenting it for themselves.

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physicsuofraui

Discussion Starter · #13 · 6 mo ago

If they are using those sensors I am guessing they couldn't patent anything specific to that sensor since Dallas Semiconductor would probably say it infringed/violated their patent (to them the more products with their sensor and protocol the better).

That is the sensor I actually use and I use the 3-wire configuration currently.

Patents can get ridiculous. I guess I won't bother reading it, thanks for doing it for me.

Guy1000

· #14 · 6 mo ago

US Patent Application for GRAIN BIN WITH TEMPERATURE AND MOISTURE SENSOR CABLES Patent Application (Application #20180372406 issued December 27, 2018) - Justia Patents Search This is the patent that I was referring to. It doesn’t list specific sensors but it includes 3 wire moisture cables.

Joel Hubert

· #15 · 6 mo ago

If you are only doing something for yourself and aren't selling it, a patent doesn't really apply to you. It is only meant to control the manufacture and sale of a particular product/idea.

BTO Fama

· #16 · 5 mo ago

as long as you arent taking their exact product and copying it patents are useless. people have done that and the patent still doesnt hold up in court. patents have become a marketing thing in north america cause as soon as you go overseas the companies who manufacture the products will just sell it to less know companies in developing countries.

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