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DIY Temperature Monitor Keeping Cables Straight

1325 Views 15 Replies 6 Participants Last post by  BTO Fama
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!
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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?
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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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
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