One, if Seek Thermal does their Christmas sale again this year, there is no point.
So if I go home and set up post objective scanning with a pair of galvanometer scanner driven mirrors and a single point detector, will you give me 200$ for recreating 1970s technology? Hint, I might have already done this in other wavelengths....
I have a pair of Cambridge Galvos with large metalized mirrors, this is a non-issue to set up.
The big issue is the Pyroelectric sensor used in motion sensors needs an AC optical signal in order to respond, so you need a optical chopper in front of your four Dollar sensor to obtain any sort of linearity. Most of them have two sensor chips wired in parallel with opposing polarity , so you have a great motion sensor when there is an optical grating in front of the sensor. However this makes a for lousy imaging sensor unless you mask 1/2 of the detector using an aperture. I can order a discrete sensor, but by the time I pay that much, I might as well buy the Melexis array development kit and scan across that. The issue then becomes the very slow I2C readout for that sensor.
By the time I get you an image update with a pair of mirrors moving at 60 Hz and 1 Khz or so, there will be a serious change in even a static scene. This is why early thermal viewers used an expensive spinning, mirrored, polygon, or an expensive resonant scanner that scanned at 1/4th or 1/2th the video line frequency.
For the resonant scanner, this means you need a way to sense and linearize the sinusoidal variations in pixel clock. To get the update up, you need scan bidirectionally as well.
I see the resonant scanner / linearizer board combo on Ebay about twice a year. They are still used in a few Confocal microscopes.
Which is why the mechanical IR video cameras were rare, and expensive.
You could try a Nipkow disk, if you cooled the disk and had a very hot scene, like a propane torch or soldering iron in the near field. Single element lenses with suitable coatings are sold on ebay for replacement focusing lenses for CO2 based Laser Cutters. This is all a long shot because any scanning process really, really, reduces the chance of such a cheap detector working well.
To get good video, I would then need Liquid Nitrogen from work, for the Mercury Cadmium Telleuride detector I have on my desk.
The moral of the story is the modern Bolometer pixel is so much much more sensitive then the ancient TGS Pyroelectric detector, its not even funny.
Besides, My friend Phil Hobbs was working on a better way with his Footprints project....
Scroll down to "A 10$ Thermal Infrared Imager", on his page:
http://electrooptical.net/http://electrooptical.net/www/footprints/fpspie11.pdf Phil would be the first to tell you that he had the resources of IBM Research at his disposal.
Steve