This is my first question on Electrical Engineering forum. I am preparing an IoT system for rugged and extreme conditions with Raspberry Pi and Arduino. The requirements for this sensor are as follows,

1) should work for high temperature (200+ degree centigrages)

2) should work in oil and water

3) should work in dust

4) should transmit the data with wireless

5) should consume low power

Please do let me know where I can find such sensor?

  • \$\begingroup\$ You are apparently asking for a complete electronics package, not just a sensor. How hot, exactly, is "hot"? 50 C, 60C, 100C? it makes a big difference. Do you expect the package to be submerged in hot oil? If so, you're probably in for a very expensive bit of kit, since hot oil will penetrate almost anything. Plus, of course, any wireless link will not work well when submerged. \$\endgroup\$ – WhatRoughBeast Oct 25 '16 at 4:52
  • \$\begingroup\$ A Pt100 element is a pretty standard go-to solution for industry applications. \$\endgroup\$ – Arnfinn Oct 25 '16 at 5:23
  • \$\begingroup\$ Thanks a lot @WhatRoughBeas. I have edited the question accordingly. \$\endgroup\$ – Ashwin Pajankar Oct 25 '16 at 5:26
  • \$\begingroup\$ When you say 200+, does that mean 200C? Or 200F? Generally speaking, electronics do not function at 200C. Thermocouples can function up to 200C (and much higher) with no problems, but the electronics itself must be in a cooler location. Would that work for you? \$\endgroup\$ – mkeith Oct 25 '16 at 5:37
  • \$\begingroup\$ @mkeith Thanks a ton Sir. I have edited the question. Yes. Thermocoupler would definitely work. I will read about those. My requirement is that the sensor should read and relay the data to the remote location. Can thermocoupler be connected to electronics? \$\endgroup\$ – Ashwin Pajankar Oct 25 '16 at 6:03

This is the kind of thing that I do all day long. One area for you to examine is called fiber optic thermometry (or phosphor thermometry or fluoroptic thermometry.) Some fibers can be built to withstand as much as \$450\:^\circ\textrm{C}\$, and more if you have enough money. They are very resistant to chemical attack, as well, and can be built to use very narrow fibers or rather larger ones, as well. Typical operating temperature range will be from about \$-200\:^\circ\textrm{C}\$ to a little over \$300\:^\circ\textrm{C}\$. Your range fits squarely in there. Inexpensive precision will be on the order of a few tenths of a degree Celsius. Accuracy, about half a degree. These probes are used inside of power substation transformer cores, for one example category of use, which are filled with rather hot oil and the fibers need to last decades in that environment. They can be low power, as well. But you haven't specified that. (You also haven't said how often you need a measurement.)

I've even done this with sapphire light pipes, which can withstand quite a lot of abuse, chemical attack, and temperatures probably over \$1900\:^\circ\textrm{C}\$, when they do start to get near their melting point. But that was done in a combo sensor which used phosphor for temperatures up to about \$400\:^\circ\textrm{C}\$ and pyrometry methods (same sensor installed in a space shuttle heat shield) above that. That single sensor works from \$-200\:^\circ\textrm{C}\$ to a little over \$1900\:^\circ\textrm{C}\$ using the same instrumentation box. But you'll pay for such fancy capability.

Fluorescent thermometry like this can even work by painting a ceramic mixture on the surface of a jet engine blade and pulsing light onto it while it operates at full speed, making in situ measurements in places where you'd think there was no possible way to do it. It's pretty versatile and has its place.

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