General > General Technical Chat
Cheap 'human' non-contact thermometers
najrao:
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?
Berni:
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.
Gyro:
--- Quote from: najrao on December 20, 2021, 10:31:32 am ---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?
--- End quote ---
Not 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.
najrao:
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 identifying what fails, and if the infrared source/sensor, what is it, and could it be cannibalized from another thermometer? Or sourced as a replacement part. There is no type number on the little pcb which carries the sensor. It has 4 connections. That is all we have.
MK14:
--- Quote from: najrao on December 20, 2021, 10:31:32 am ---I read in a manual that they only last for 'up to' 40 000 clicks, and indeed may be so.
--- End quote ---
You 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?1521030777
It appears to say:
--- Quote ---its longevity is guaranteed for 40,000 takings
--- End quote ---
Which 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.
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