HikMicro Mini 2 Plus - Anyone with the same Problem? (Solved!) - Page 1
Forum section: electronics / general

author: TurboTom
author_rank: Super Contributor
timestamp: August 23, 2024, 09:22:23 am
content: Recently, I got the mentioned LWIR "Adapter" at a bargain which works quite well otherwise -- I especially like the adjustable focus and the high frame rate -- but shows a peculiar "defect" after self-calibration:Upon "Cold Start" with the lens cover on, the image is uniform with only neglible variations in temperature over the image. After a few self calibration periods (audible clicks of the shutter), a gradient develops that finally spans approx. 2K in a diagonal direction. It clearly appears as if some component inside the camera heats up and either reflects in the shutter or heats up the shutter lid unevenly. This gradient also clearly shows in thermal images with low thermal contrast. High-contrast images are quite good, obviously.I'ld like to know if this problem can be observed with other specimen of this device, hence if it would make sense to return my Mini 2 Plus for a replacement.Thanks for your thoughts and input!Cheers,ThomasAttachments: Thermograms directly after cold start, after approx. five calibration periods (both with lens cover on), and two high contrast shots of a tiny tube amp project I'm currently working onEdit: Had to re-upload the thermograms since for whatever reason, they got displayed upside-down

author: Francesco Ang
author_rank: Newbie
timestamp: December 19, 2024, 04:25:21 pm
content: Hello, I bought a secon-hand one some months ago. It is a V2 version (manual focus). Same problem. I contacted them through the chat, and then emails. I presented the problem, which is even worse than yours (I get 4 K between the diagonal ends). They were quite kind, but actually they didn't provide me with a clear answer. I would like to go on and force them to replace it, since it is clearly out of declared specification. What did you do in the end?Francesco

author: TurboTom
author_rank: Super Contributor
timestamp: December 29, 2024, 12:38:40 am
content: @Francesco -I went through the same experience -- contact with HIKMicro through the contact form on their web site and elaborated on the problem. I quicky received a friendly reply with the hint to test the LWIR adapter with some other objects to verify the problem. As if I contacted them for fun. My impression is they try to be helpful but the personnel in charge of replying to the inquiries has little knowledge on thermal imagers...An experience in a high-tech store in Baoji, China (of a well-known quality brand for laptops among other things) comes to my mind: I've been looking for a laptop / notebook computer with very decent performance so I could run my CAD software for presentations at customer's locations on it, and intended to compare prices since we had some leisure time. I asked the personnel (who really tried their best to help) about the graphics processors used in their gear and the suitability for CAD 3D displaying jobs -- they simply didn't understand what I was talking about. It cannot have been the language alone, we had a native mandarin speaking individual with substantial technical background with us, but this still didn't help. It felt almost like talking to someone without any in-depth knowledge of their own products. Quite a peculiar situation.And this reply from the HIKMicro service gives me the same impression. If I had some time and found a way to reversable disassemble the "gadget", it may well be possible to identify the problem and work out a "DIY" solution. But since I've been quite busy recently, I didn't get back to HIKMicro's service. After all, I guess I still should do....All the best,Thomas

author: Francesco Ang
author_rank: Newbie
timestamp: March 14, 2025, 08:50:31 am
content: @Thomas: After some exchange with HikMicro service, they offered to replace my camera in order to solve. Mine was still covered by Warranty (bougth on AMZ). I spoke with Aisha, very kind. After sending mine to them, they sent back a new one to me. which has just arrived. This one is definitely better. The isothermal image appears now really isothermal, with differences in the same picture of say +/-0.1 °C. Also, the image is quite more defined compared with the older.I’ve noticed a sticker on the outer new box telling "New", like it is a new version. The older camera s/n was EA1072xxx, the newer one EA2565xxx (start with "2" instead of "1"). I cannot tell whether the improved operation is given by a different hardware inside or because the older was defective, but I would say the latter, since the camera was even getting hotter than this one, and this was not reflecting the declared power consumption.I hope you are still in time to ask for yours to be replaced.Regards!Francesco

author: JOSDHO
author_rank: Contributor
timestamp: May 14, 2025, 06:40:35 am
content: I’ve touched mine after it’s been running for a while. It gets pretty hot. The image doesn’t look as clean as it does right after boot. Maybe the heat is throwing off the calibration. For the price though, I’m probably being picky.

author: TurboTom
author_rank: Super Contributor
timestamp: July 12, 2025, 01:51:59 pm
content: Well, curiosity got the better part of me and I decided to tear down the Mini2Plus... I just wanted to understand why this gadget shows this type of inhomogenuous background. Interestingly, all the small "Cube" style cameras appear to be designed completely differently, some with glued plastic housings, others with screwed metal enclosures. Also the chips that make them tick seem to be of completely different origin. Here, an Efinix Titanium Ti60F100S3F2 gets used.The hardest part of the disassembly was getting the "HikMicro" label that covered the casing screws off the recessed rear face... I had to heat the whole camera substantially to soften the adhesive but still wasn't able to remove the label without leaving any tracesAnyway, I cannot complain about the build quality of the camera at all -- everything's tidy and solidly made. Initially, I thought the chip located at the edge of the (open) calibration shutter was a regulator, unevenly heating the shutter, until I found out that the STS31 is a highly accurate temperature sensor...But the other side of the same PCB accomodates two linear, ultra-low-noise voltage regulators (Gongmo GM1201 ~ LT3042) that may very well lead to an uneven heating of the shutter. I'll probably experiment with some thermal shielding of the area between the PCB and the shutter. But I need my other thermal camera that's currently located at our production location, to verify effectiveness of the shielding attempts.So what's left is to enjoy the teardown photos... Have fun!

author: Fraser
author_rank: Super Contributor
timestamp: July 12, 2025, 02:55:54 pm
content: Excellent quality images. Thank youAs you say, the build quality appears excellent

author: TurboTom
author_rank: Super Contributor
timestamp: July 20, 2025, 06:17:24 pm
content: This Sunday I decided to have a closer look at a possible solution for the inhomogenous background problem of my thermal dongle. Guess what? I succeeded!Here's what I found upon removal of the shutter assembly from the FPA board: The shutter "hand" is made of plastic. The poor thermal conductivity of this material means that local heat sources can easily result in a thermal gradient across the surface of the shutter, which would be interpreted as constant temperature by the compensation routine and result in the uneven background.Since there was ample distance (relatively speaking...) between the shutter surface and the FPA, my idea was to attach some highly thermally conductive coating to the shutter. I searched my basement and found some very thin copper sheet (0.2mm) of which I cut a tiny rectangle of 6x4mm² to just match the surface area of the shutter hand. I flattened it by means of a steel roller of good surface quality and attached it to the shutter (I used simple contact glue for this job). Fortunately, the return spring of the shutter motor is strong enough to cope with the additional few milligrams...Since copper is highly reflective in the long wave infrared range, I had to make it opaque. I decided to try the thinnest kapton adhesive tape I could find in my basement and attached it to the copper suface somewhat skew...never mindAfter that, I cut the accessible edges to size.Apparently, this worked very well - see the attached thermogram (taken after approx. two minutes of operation and several shutter operations with theprotective lens cap on) and compare it to the one from my opening post of this thread. I'ld say, quite some difference!So if someone's got one of these tiny "thermal dongles" and observes the same problem, this is how it can be solved. Yet, it's definitively no job for the faint of heart since there are many chances to mess things up! Good luckCheers,Thomas

author: Fraser
author_rank: Super Contributor
timestamp: July 20, 2025, 07:18:35 pm
content: Excellent workThe only thing I would do differently is to spray the metal plate on the FFC flag with a high Emissivity paint that I already have in stock.Whilst Kapton tape will work, as you have proven, the traditional approach is a Matt black high Emissivity coating as this avoids the possibility of a tape detaching over time.As you say, plastic FFC flags are not ideal and there is good reason why professional thermal imaging cores use a thin metal flag that is coated with high Emissivity black paint or special coating like nano Matt black. The location of the FFC flag temperature sensor is also important in high accuracy measurement systems.Fraser

author: TurboTom
author_rank: Super Contributor
timestamp: July 23, 2025, 06:41:58 pm
content: Fraser,thanks for the hint. Is this paint you're referring to something special or just plain black matte spray paint? If it's the first, could you possibly disclose the make and type?I chose a the Kapton (polyimide) tape as a coating since we used to use it at my former job as an aid to increase emissivity of bare metal surfaces to be able to pyrometrically measure surface temperatures more accurately -- with considerable success.I just found a scientific paper where an absorption plot of aluminized 50µm (same gauge as the tape I used) polyimide film has been reported (attached). Except for the relatively narrow dip to 50% around 10µm, it looks quite favorable. Hence, I'm not too sure if using a "proper" high emissivity paint would make a noticeable difference.But I may try anyway just to find out...Cheers,Thomas

author: Fraser
author_rank: Super Contributor
timestamp: July 23, 2025, 09:11:03 pm
content: Thomas,I recommend Krylon Ultra Matt black paint as it is used by some thermal camera manufacturers known to me. It is a specialist Industrial camouflage paint. NASA tested this Krylon paint with very good results and it was considered the next best option to specialist, hard to source paints that most of us cannot obtain in small quantities.https://www.krylon.com/en/industrial/products/specialty/camouflage-painthttps://www.tactical-kit.co.uk/krylon-black-spray-paint-10918-p.aspThe issue with Kapton tape is that it is an adhesive tape as that can present a problem if it peels away from the substrate to which it is attached.Fraser