Applied Science - 2010-10-08
I am trying to develop a low-cost DIY thermal imaging device. The commercially available thermal imaging cameras still cost well over $1000 because of high production costs and low demand. Many hobbyists would like to have a cheap thermal imaging camera even if performance is not as good as commercial or military units. My goal is to build such a camera. In this video, I am testing one possible approach: Using a very thin projection screen that is painted with thermochromic liquid crystals. These liquid crystals change color in the temperature range 77*F to 86*F. Ideally, the projection screen housing would be heated (or cooled) to 77*F, so that all incident thermal radiation would raise the screen temperature higher than this, and immediately cause a color change.
Nice project.
Those little thermal viewports would make awesome toys.
A year or so ago I watched a project on TV that used an aftermarket thermal imaging device. It did not have anything but the camera that hooked to a notebook for viewing. The cost was said to be 500 bucks, but I was never able to find the outfit who supplied the unit. It was used for a robot along with a night vision unit. The unit came out of the box as a circuit board that was installed into a small plastic job box about 4x4x2 inch. if you know of this unit let me know. Cheers and good luck!
Been watching your videos for years....
Just found this... Holy fetch.... Passive!? Where is the follow up.
Where do you purchase the liquid crystal paint?
Well, slow is certainly an issue for S&R. The problem with this is that it wouldn't reliably show any detail about temperatures below 77F, since that's the floor, so it wouldn't be of much use, for instance, searching for people in an avalanche. The signature is already fairly minimal with a nice FLIR camera, raising the temp floor wouldn't help at all. What would work fine is a rapid scanning pyrometer. A 40 degree difference would indicate MP is present, which works in the above situation.
It sure would be nice for this to be affordable enough to make a "lie detector" device that parents can afford, but it would have to be sensitive and quick enough to detect slight temperature changes around the eyes. I'd buy one!
You can't be serious...
Amazing idea. Just a couple of thoughts in case you get to tinkering again. Could you use soot from a candle or similar as the substrate for the liquid crystal paint? Then possibly use your vacuum jar to do a poor man's vacuum deposition of the crystals on to the surface of the soot, or just mix the paint in with the wax before burning? Lastly, 'shine' the IR directly on the painted surface, rather than through the substrate. Short focal length of the lens might make that impractical? Dunno.
I could only suggest to use ZnSe lenses, they are also cheap and more transparent AFAIK,
Silicon can definitely be used for around 5um. Germanium @ 8-12um
To heat or cool the projection screen housing, a Peltier Effect (PE) device may be a good option, you can change it from cooling to heating, by switching the polarity of its power supply leads. A PE device has no moving parts and there is no heat exchange fluid involved.
All you'd need would be an electronic temperature controller.
A small PE device may suffice because of the small range of temperature required. Operating the PE device at full current may also not be necessary because with a PE device, operating at its full rated voltage and current, one side gets cold enough to freeze water to ice, and the other side gets too hot to touch. The temperature controller would require a current output with possibly the ability to switch polarity automatically as needed.
Of course the sixe of the PE device would depend on the thermal mass of the projection screen housing, and any internal warm/cold air.
Thermochromic paint maybe would work better? I heard there are developments in Terahertz CMOS cameras and THz is even more interesting than FLIR because it penetrates walls.
Cool. Instead of a plastic bag, why not spray the paint onto a thin sheet of PVA? After the paint dries you can then immerse it in water and the PVA will dissolve away.
Dang this is very clever. Like a ramenspec scope but for heat =)
When you air brush it did you add anything to the liquid
This is sooooooooooooo awesome!!!!!! I am planning to make own!
Have you tried it?
How about clear plastic wrap stretched over a cylinder and soaked overnight in the paint that way it wont be just a top coat on the film and the image wont be as grainy because of the plastic wrap, just an idea.
To sauroman1; Silicon cannot be used in place of Germanium because Silicon is opaque to thermal infra red frequencies.
have you tried fiber-optic in a bunch as the screen and only paint the very tips''''''
I saw you were in PM the other day, nice one! Im interested in your projects espesically your cryocooler and your thermal imaging. Do you have any tips on where to buy the special parts for your stirling cooler? Thanks
nice project !
I have found germanium blocks real heat radiation. You cannot sense the heat through it like you can glass. It blocks heat where glass is transparent to heat. So I wonder what is going on here. What happens if you do not use the germanium?
I have been thinking: there is something significant happening here, but it is not heat radiation as we know it, I think it is electricity. It is a real mystery, one I have been working on for some time. You test what I am saying: whether the germanium blocks the heat radiation.
Do the thermochromic liquid crystals respond to current?
What if you remove the IR lens of a regular webcam and let the ccd w/o the IR record the image?
man working good i think you should try reverse engineering of some cam and then try direct trying takes years
this is very interesting. so was there any second day or a third day?any updates?
Did you get any further with this?
I wonder what you would see if you used that germanium lens on a standard webcam instead of its lens arrangement, or perhaps a super low lux cctv camera at night?
Probably nothing. Webcams aren't sensitive in those wavelengths.
can you actually make sunglasses out of those? would Lab be able cut that lens and shape it to fit into an actual frame?
The IR would probably be not very good to shine in your eyes all day.
how about using aluminum foil instead of the plastic from the bag. It is very thin and it has a very low thermal mass.
Low thermal mass??
Even if it had, it's a very good conductor of heat.
Would it be possible to fashion the made lens into goggles as well as a camera lens?
Did this idea go anywhere?
Maybe cling wrap would work better
Any new development?
you should put a cameralens on or colored rappers
did this progress?
Any updates how to improve design? I'm looking to make IR camera for painting investigation so I need high resolution preferably SWIR and MWIR? What spectrum it can display? You use carbon based pigments? Is vanta black better? In theory it would be also possible to image even THz or microwaves with powerful enough source and UHMW HDPE?
Why would you want to use vanta black?
@@stefanmayer444 Because it's blackest material and has lowest reflectivity what makes it excellent at absorbing broad spectrum of light, liquid crystals need anyway black background. Also carbon nanotube vertically alligment "forest" has good thermal conductivity in one direction mostly. I guess soot can cheaper alternative. However I don't how well they absorb infrared. Any suggestions what to use instead to achieve good sensitivity say in MWIR range? I was thinking also of cooling one side with Peltier to increase sensitivity.
@@RynaxAlien Yes I have a view thoughts about that, but just to clarify; In what order was he coating the plastic film?
@@stefanmayer444 Basically there need to be three layers as thin as possible. One is to act as frame in this case thin streched PE bag. Then it's coated with black or other material that has good absorbtion in desired wavelenght. And eye facing side is coated wth LC. I got LC for nails which already comes with adhesive so I was thinking just to make it by pressing evenly with two teflon films. LC has to be thick enough to produce more vibrant colors. But again making it too thick introduces thermal dissipation problem which results in blur and sensitivity loss. So ideally you want there to be insulated "pixels".
You used carbon based pigment? I want to see broad thermal specrum mainly MWIR. Is there alternative to germanium lens? It's important to have also wide aperture lens since many use F/1.0 lens
Do you have some pictures to show up?
@bkraz333 Hey thanks a lot fr the awesome tut i will try it out but i wanna know if you can Increase the temprature range like 24 celcius to 40 celcius? I want to use it for fever detection and stuff kindly reply, P.S u deserve a nobel ;)
Have you achieved the 24°C goal?
i am trying to do that very hard to get that paint
Have you tried it?
Please tell me more about the crystal paint from Edmund Scientific. I can't find such a product on their site. Do you have the model number of the product you can share with me?
Bill Bass Unfortunately, Edmund discontinued the product. I went back to order more, and the item number is no longer available, and has no replacement.
Any news of ideas where one could find replacment ?
@@NccWarp9 Solar Color Dust, or something like that
@@NccWarp9 some color changing nail polish is made with this stuff.
can i buy one?
@bkraz333 Hey thanks a lot fr the awesome tut i will try it out but i wanna know if you can Increase the temprature range like 24 celcius to 40 celcius? I NEED ur HELP ASAP!! plz plz I am working on a very imp medical project for a science fair,So i need ur help and wats the refresh rate like?
waaaaaaat?
Thermal reader
@AppliedScience - 2013-01-27
Not a whole lot. The CCD is designed to be sensitive to visible and near IR wavelengths. The thermal energy will just heat up the CCD, and the tight thermal coupling between cells will cause the whole thing to heat up almost uniformly.