I have the Milwaukee M12 , It was purchased mostly for inspecting the cylinders of an engine , works fine for that. Don't see why it wouldn't work in a wall you wanted to inspect.
Yup I had one that plugged into my smart phone. Used for automotive purposes. I think I payed 30 bucks for it. Worked pretty well. also used a snap on unit. Worked much better but $$$$.
I have the harbor fright version of that...it works fine, but sometimes things that aren't close to the lens are hard to see great details of...and mine is not self leveling, so you have to figure out which way is up...can be very disorienting to tell what you are looking at exactly. (when used in a wall, not so much in a cylinder) I've used a cell phone borescore too...it will fit in a lil smaller hole (3/8-1/2" maybe?) But IMO it has many of the same issues...plus, being that the wire is more flexible, it can be hard to push it to the exact spot that you want, unless it's a confined area, like a 2" pipe for example.
I too bought something off Amazon years ago to see what's in chimney of this old house. Plugged into my phone and a previous member here helped me discern it, I was pleased, didn't cost very much. Also I wonder if a FLIR would could pick them up? Anyone know?
FLIR = Forward Looking Infra-Red. the images are typically white hot or black hot. Meaning if it shows heat, it will be either more white or more black. A really good camera will let you switch between the two. British Army 'Introduction to Thermal Imaging' (youtube.com)
When I clicked on this thread I thought it was going to be a colonoscopy thread. my doctor has been suggesting.......
