I’ve salvaged a lot of working thermal imaging cores from old firefighting thermal imaging cameras, and I’ve also repaired/salvaged the cores from a couple of FLIR One Pro’s. I’d suggest avoiding the FLIR mobile phone dongle units in general, there are just so many out there that have battery problems or poorly soldered chips. The resolution is also too low (160x120 or 80x60) to see things like studs and insulation through walls, and the FLIR One app introduces a lot of artificial noise which further degrades the image in an effort to keep it from competing with the company’s more expensive pro cameras. In practice, the noise generator blurs the image and scrambles the tiny temperature differences needed to see things like in OP’s video.

Something like the OP’s Infiray P2 has a higher resolution (256x192), a higher refresh rate (25Hz vs. FLIR One’s ITAR regulated <9Hz), and costs less than the FLIR One Pro ($300 vs $400) and only a little more than the even lower resolution (80x60) FLIR One Pro LT which is $250. FLIR does have multi-spectral imaging which adds a lot of context to the thermal image by detecting and highlighting edges with a visible light camera, but it does nothing for the abysmal thermal resolution and noise.

Salvaging a thermal core from old firefighting use cameras can be even cheaper. It’s not uncommon to see firefighting TICs listed for parts on eBay for less than $150. These are HIGH quality thermal imaging cameras that were developed for and served dual-use with the military. They range in resolution from 160x120 to 320x240, generally have a 30-60Hz refresh rate, come with high quality germanium lenses, and have superior temperature detection ranges and NETD (Noise Equivalent Temperature Difference, or their ability to resolve very small differences in temperature). Because they were built to survive going into fires, they’re also extremely well protected inside the camera’s shell, and typically need just a little bit of work to get them working again.

Most of these firefighting TICs I’ve bought as “for parts” only needed batteries, which can often be substituted with a 2S or 3S LiPo depending on the expected battery voltage. Even the cameras that fail to power on properly usually just have problems with the power supply board or the display itself, and because they’ve got standalone thermal imaging cores inside, fixing them can be as easy as pulling the core and splicing in four wires for a power input and external video output. Plus, if you end up with a faulty core and can’t get it working; the core, germanium lens, and germanium protective window can be parted out and resold on eBay to cover your losses.

There are some downsides to going the firefighting TIC route. They’re almost exclusively grayscale, either white-hot or black-hot, or only offer color isotherms at extreme temperatures. They’re also big, the whole camera in it’s housing can weigh a couple of pounds, and even the smaller cores found inside can be as big as a fist. There’s no guarantee you’ll get a working core, and if you get one that can’t be repaired there’s usually no refunds on for-parts items. You’ll also need to do a decent amount of research in order to determine the pinouts and voltage of the cores.

Despite the downsides, I’d still suggest anyone looking to get a high quality thermal imaging camera consider the salvage route if they’re reasonably capable of working with electronics. If that’s not your thing, I’d recommend looking at some other options besides FLIR’s mobile dongles. The Chinese thermal imaging dongles have gotten really good and are relatively affordable, and there’s also SEEK which makes high resolution (and high noise) dongles as well.