#1486

Episode 1486
how are thermal (IR) camera sensors constructed.
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[@ivanpopovic9503]

Few months ago I gave you a very bad comment about Your rewiev of Textronix power supply... This here was one of the best short explanations of IR measurement and basic physics behind it. Great great job! Just great! Short, simple, perfectly clear explanation.

[@IMSAIGuy]

Score: Ivan 1 : Imsai 1 😀

[@cmuller1441]

The key part is that you use a temperature dependant resistance. Then you use a known tiny current and measure the voltage to find the resistance and the corresponding temperature. Also the trick is that you reach an equilibrium when the absorbing element is at the same temperature as the emitter (ignoring losses). That's because the absorbing part becomes itself an emitter when it heats up.

[@craigs5212]

Thanks for the nice video. I got one of the Uni-T UTi260B thermal cameras a while back. Didn't think I would use it all that much but its been quite useful around the lab. Great verify your design has good thermal margins, finding faulty components and shorts. Would have been great back in the 70's when we had boards with 30 or more TTL devices on them. Bad components on busses were always a pain to find. Wan not uncommon to have 10% DOA TTL components.

[@hgbugalou]

I got a Flir one a while back and its been incredibly useful in all kinds of projects. I thought I would barely use it and end up using it all the time and it can really save you time and effort.

[@alklapaxida850]

nice vid, these can are so useful in any field that anyone cares to mention i use them in RF, electronic, automotive, mechanical. chemical applications

[@johnwest7993]

Measuring bolos in the wild. "I'm blinded by science!"

[@monad_tcp]

Hum, delicious. Now I want cake for some reason

[@IMSAIGuy]

🎂

[@chaorrottai]

Darn, not what I was hoping for.... Looks like I have no choice but to got with MCT photodiodes.

[@kmgflavin]

Wonderful explanation and lead up to the construction of the device! Have you thought about covering deformable mirrors? They are made a similar way.

[@IMSAIGuy]

I designed optics for the TI micromirror chips

[@cmuller1441]

Why adding dashes or minus signs in the units? There's nothing between μ and m and a multiplication between m and K. It's μm multiplied by K: μm*K μ is the 10^-6 S.I. prefix like k is the 1000* prefix for km (1km=1000m) Also be careful with case. k vs K: k is a prefix, K is the Kelvin temperature unit

[@str8upkickyaindanuts289]

I was under the impression that the IR sensor used in the touchless temp probe was using a pyrometer thermopile, essentially a thermal couple type sensor rather than a resistive sensor. Funny that I don't know this because I used the MLX90614 for years in designs to measure the voice coil in a speaker as a feedback in high power audio systems to prevent thermal destruction.

[@IMSAIGuy]

simple 'one pixel' temp sensors do not use a microbolometer, there are several other temp sensors

[@wilurbean]

Why not use semiconductors like diodes with their exponential charge carrier relatio ship to temperature

[@PatientZiro]

Brilliant! Thank you for the explanation! I found your channel few days ago and since then I learn something new every day! Keep it up!

[@fractalnomics]

13:54 Radiant heat does go through glass, think of an incandescent lightbulb or your window and the sun. And actually, germanium blocks radiant heat, try it yourself.

[@IMSAIGuy]

wp.optics.arizona.edu/optomech/wp-content/uploads/sites/53/2016/10/Saayman-521-Tutorial.pdf

[@danielepatane3841]

I wonder if a device like that may be used to measure rf power from a tx with a right implementation .....

[@DirtyPlumbus]

Suddenly $300 for an IR camera seems like a great deal. Lol

[@AJMansfield1]

I thought microbolometers were capacitive sensors rather than resistive? Using thermal expansion to move the top plate closer to or further from another large pad behind it to change the amount of capacitance.

[@kmp8563]

Not sure if what you're describing exists, but that's an interesting concept. VOx microbolometers use thermal coefficient of resistivity. The temperature of the VO2 affects its electrical resistivity to a measurable degree

[@K1ZEK]

That was a struggle as I haven't had my first coffee yet.😅 Give me credit as I stayed till the end, though I didn't read the other comments yet😊. Leo ☕

[@sammin5764]

🌟🌟🌟🌟🌟

[@__--JY-Moe--__]

yea! the rodeo! Cadillac has had bolo's since 2000! they should have a 360` IRcam in all car's!! just say'n! if U've ever been blind sided by a deer or moose. U'll want one! outside on U'r car! 🤣 a funny thing! u'r doing a 1980's formula! 1960 formula would have been 5X longer! It's much fun'er 2 equate in long form! I discover much more rather than just make'n cube steak! yup! it's super sensitive! U'r dog tracks were cool !! edmund scientific wantabee!

[@bobkozlarekwa2sqq59]

555nm, the wavelength of the light emitted by a firefly, and coincidentally the part of the visible light spectrum that human vision is most sensitive to. Coincidence or is this all a piece of natures puzzle?

[@__--JY-Moe--__]

but if nature was just nCr, wouldn't every1 own las-vegas!

[@amarpersaud2950]

About 550nm is where the peak of light emission for the sun is. Eyes developed mainly to be able to detect this color of light, hence human vision is more sensitive in this area. The peaks don't line up exactly because many creatures use different chemicals and proteins to achieve the same effect; for humans the OPN1MW ("green" sensitive protein) has a peak at 530nm and OPN1MW ("red" sensitive) has peak at 560nm. Vision cuts off at around blue/violet beyond that range, things like air and water become opaque to those frequencies of light, and I'd assume low IR sensitivity in the eye probably because it could impart heat and damage the eye. Humans can still see IR in some capacity as a violet like color, but it is overshadowed by other colors, and the eye itself filters out a good majority of it.

[@bobkozlarekwa2sqq59]

Yes, and the bluish cutoff likely accounts for why blue Christmas lights appear to be diffused or out of focus.

[@ThinklikeTesla]

And the 555 is coincidentally one of the most common ICs used by electronics enthusiasts to make blinking lights. I want to believe.

[@IMSAIGuy]

blue is blurry because we have fewer blue cones than green or red

[@MrMegaPussyPlayer]

11:48 Higher resolution ones have already been spotted in the wild. Though, that might also be Chinese lying to your face.

[@bruceblosser384]

So many draw the radiation graph backwards! It drives me NUTS! put the longer wave lengths to the left, and the shorter wave lengths to the right!!!!!!!!!!!!!

[@IMSAIGuy]

guess it depends on your upbringing. All optics folks do it this way: simple.wikipedia.org/wiki/Infrared_spectroscopy

[@bruceblosser384]

@@IMSAIGuy I have a background in photography and astronomy.... so I guess I should know better... but i always remember the Electromagnetic spectrum charts, with Radio Waves on the far left, and UV and X-Rays on the far right

[@IMSAIGuy]

@@bruceblosser384 If you think about it, all graphs usually have small number left and big numbers right. so wavelength should be no different. I have seen all those graphs you are thinking about and they plot frequency and then label the graph wavelength. the reason is wavelength can be used for all, frequency not so much.