Cheap 'human' non-contact thermometers - Page 1
Forum section: electronics / general

author: najrao
author_rank: Regular Contributor
timestamp: December 20, 2021, 10:31:32 am
content: Thousands, if not millions, of these handhelds are being discarded after they no longer work. I read in a manual that they only last for 'up to' 40 000 clicks, and indeed may be so. I checked a few: the displays still work, but report 'Hi' or 'Lo'. So it is the sensor. What sensor, and why does it have to have such limited life? Google failed me to find the answer. Seems criminal to create such waste. May be it is lucrative to the sellers to force new sales! Can we recover them to use again? How?

author: Berni
author_rank: Super Contributor
timestamp: December 20, 2021, 10:49:52 am
content: They are likely using a infrared thermopile sensor much like the general purpose IR thermometers. The sensor can be a bit delicate but it should not have a limited number of uses like that. Maybe the sensors get damaged from rough handling or blocked by dirt getting into the "optics"It is possible they have a built in kill timer that makes it dead after too many uses, very shady practice, but you can probably find out if you try reverse engineering one of these.

author: Gyro
author_rank: Super Contributor
timestamp: December 20, 2021, 01:18:19 pm
content: Quote from: najrao on December 20, 2021, 10:31:32 amNot a problem I've come across.Are you sure that isn't (only) 40000 clicks battery life? Did you try changing the battery (probably a CR3032).Even at 40000 clicks, with a fairly pessimistic 10 measurements a day (typical family twice a day?), that's still 11 years, which would be typical shelf life of the battery. I think I'd want to check its calibration well before then anyway.Edit: Yes, a good clean might well help.

author: najrao
author_rank: Regular Contributor
timestamp: December 20, 2021, 01:55:27 pm
content: Gyro, not so I'm afraid. These are used in hospitals, or even in metro stations, and may be clicked hundreds or thousands of times a day.The example here uses 2×AAA, and fresh batteries don't change the defunct status. Yes, I am sure the manual means "total service life" and not battery replacement time. Another said 'two years' as the instruments usable life.What I am after is identifyingwhatfails, and if the infrared source/sensor, what is it, and could it be cannibalized from another thermometer? Or sourced as a replacement part. There isnotype number on the little pcb which carries the sensor. It has 4 connections. That is all we have.

author: MK14
author_rank: Super Contributor
timestamp: December 20, 2021, 01:55:57 pm
content: Quote from: najrao on December 20, 2021, 10:31:32 amYou don't seem to have supplied a link or picture or quote from the actual manual.Here is one:https://d3m9l0v76dty0.cloudfront.net/system/photos/2705008/original/091a2827f12a4c29e09d06e0244fe9ea.pdf?1521030777It appears to say:QuoteWhich seems to mean, that it is suppose to work for at least >40,000 readings.I can't see why that would bother you. Since most things also have life expectancies and/or limited number of uses, before it wears out and/or runs out of guarantee.As with most things, they could be built to last longer. But it would usually considerably increase the cost.Example:You make yourself a screwdriver. You can make it quickly, using cheap materials, and it might last for 100 uses.Alternatively, you could spend weeks making it and the best and most expensive materials to make it. It then could be used by your great great great grandchildren, if you have any.

author: najrao
author_rank: Regular Contributor
timestamp: December 20, 2021, 03:01:47 pm
content: MK14, the manual you have linked to does not apply to the Bo Hui T-168, which is what I have here. I do have a manual for this, but am now unable to link it here. I attach a screenshot of the page which gives the service life as 40 000 clicks.I request that you desist from making sundry comments deviating from my legitimate request for possible technical help. Especially if you are unable to provide any.

author: tom66
author_rank: Super Contributor
timestamp: December 20, 2021, 11:13:17 pm
content: These sensors don't really work anyway. Non contact IR sensing for fever screening is done by looking at a very specific point on the face, just scanning foreheads or the back of hands tells you pretty much nothing about someone who doesn't think they're feverous, but is going into one (and that's probably the point where you're most infectious, especially because you're taking almost no precautions.) Besides, the forehead skin temperature variance between someone who is feverous and someone who has exercised is actually pretty close too.These problems means the screening process more or less requires a TI camera or very well focused thermal optics, neither of which these offer.Disclaimer - I work for a company that makes equipment like this, but this requirement is from FDA.

author: TimFox
author_rank: Super Contributor
timestamp: December 20, 2021, 11:21:59 pm
content: The manual pages posted above are not written in careful English, but I would read the "lifetime" as a minimum guarantee, not a defined or maximum lifetime.

author: Zero999
author_rank: Super Contributor
timestamp: December 21, 2021, 11:33:33 am
content: Quote from: tom66 on December 20, 2021, 11:13:17 pmI suspect the real reason why lots of these contactless thermometers have been discarded is because a huge number were purchased with the aim of controlling the spread of SARS-Cov2, but unlike the previous virus, whether someone has a fever or not, is a poor indication of infection.

author: najrao
author_rank: Regular Contributor
timestamp: December 21, 2021, 12:25:09 pm
content: The discarded ones are almost always defunct and FUBARRED. So, not a case of excess stock thrown out.

author: tooki
author_rank: Super Contributor
timestamp: December 21, 2021, 12:30:01 pm
content: Quote from: najrao on December 20, 2021, 03:01:47 pmYour original requestassumesthat the failure of your unit a) has to do with the 40K rated lifespan, and that b) it must be the sensor that failed.You have no proof for either of those assumptions, and it’s just as likely that they’re not the case.If you have a concrete failure you want to repair, give more info on it so we can troubleshoot. But your original post suggests more of a general question, which makes the “sundry” comments absolutely relevant.

author: Someone
author_rank: Super Contributor
timestamp: December 21, 2021, 10:01:27 pm
content: Quote from: TimFox on December 20, 2021, 11:21:59 pmWorse:low cost products cloned n times over, their product specifications have been through the same "telephone game" of imperfect copyingand/orlow cost item loudly proclaims performance specifications copied from contract/competitor/tender documents to "compete", item has never been tested or verified to meet said specifications. paper is cheap

author: floobydust
author_rank: Super Contributor
timestamp: December 22, 2021, 07:44:33 pm
content: I have .webm explaining the issue but could not upload- the IR sensor is not wired up and firmware gives nice 36.1C readings that move around a little.Basically, they are fake IR medical thermometers.

author: MK14
author_rank: Super Contributor
timestamp: December 23, 2021, 12:50:20 pm
content: Quote from: floobydust on December 22, 2021, 07:44:33 pmThis has a video about it. It looks remarkably like the one the OP pictured.https://www.thesun.co.uk/news/11365234/scammers-trade-fake-coronavirus-protection-gear-medicine/

author: floobydust
author_rank: Super Contributor
timestamp: December 23, 2021, 08:29:16 pm
content: Yes that's the vid, thanks for the link.I can't see any money savings there, aside from the 3-wire cable to the IR sensor and labour to solder it in. Unless it's to destroy the West by giving out fake negative fever results.Somebody came up with fake firmware for a reason.

author: MK14
author_rank: Super Contributor
timestamp: December 23, 2021, 08:41:58 pm
content: Quote from: floobydust on December 23, 2021, 08:29:16 pmIt's crazy, and totally reckless, as it risks lives. Ignoring earlier arguments (e.g. on medical grounds), as to if these head scanning thermometers (IR), are useful/safe (when NOT fakes).It would seem to be a very dubious way of making money, by selling/producing/designing fake thermometers (IR). Because it could literally end up killing people.Some of the really cheap Chinese stuff, is known to have potential safety hazards, such as electric shock, fire and maybe other hazards. BigCliveDotCom youtube channel, often details such things.The front blue keyboard layout/section and its colour. Seem amazingly identical, between that video and the OPs supplied picture. Even the label on the side seems rather similar or identical.It would be nice to see big/clear decent photographs of the inside (especially), of the OPs unit(s). So, we could judge for ourselves.It is a bit like the jellybean cheap/plentiful, op-amp parts, which the Chinese still fake, just to save a cent or so, on the genuine parts. It just seems so silly, really.

author: cdev
author_rank: Super Contributor
timestamp: December 23, 2021, 10:16:19 pm
content: Maybe accurate instruments cost more because they work better.Coronavirus is supposed to be "the money making opportunity of a lifetime". And its safe to say it also drove up prices of many goods.. Items are supposed to determine their own prices in a self-regulation process, At least that is my understanding of the economics of prices as elucidated by Friedrich Hayek. and debunked by Karl Polanyi.

author: ejeffrey
author_rank: Super Contributor
timestamp: December 24, 2021, 10:32:35 pm
content: Where are you getting these? Do you know their history? How many are there? It sounds like you are dumpster diving and testing discarded devices?There is no real wear mechanism except the switch. If the switch is fine and the sensor isn't working my guess is that it was dropped and something inside broke or got misaligned so it was thrown away. Nothing to do with a 40,000 click lifetime, but these are built cheap and flimsy.

author: Zero999
author_rank: Super Contributor
timestamp: December 25, 2021, 08:33:13 pm
content: Quote from: cdev on December 23, 2021, 10:16:19 pmBecause they're useless in preventing the spread of SARS-Cov2?