OK, strange question: I fried my digital thermometer apparently through over-washing. (#%@-ing electronics!) To be fair, we probably didn’t need to be taking our temperatures every hour, but the panic was new back then. Anyway, the replacements I ordered a month ago won’t arrive for another month or so. (#%@-ing hoarders!) However, I realized today that I do have a multimeter, and it has a thermistor attachment. Could I use that? I guess what I’m asking is where should I stick it?
If you want it to be real time and always running, rectally would probably make the most sense. Axillary would probably be more convenient, but you might have to adjust the numbers you’re expecting, I think your armpits run cooler than under your tongue.
That kind of temperature probe has stiff wires which I wouldn’t want even in my armpit. I’d lodge the probe under a sweatband or knee/ankle brace, and watch changes in temperature, rather than trying to detect and compare an absolute number.
The digital thermometer you used to use is a thermistor.
If you cared about reading an actual temperature, you’d need to calibrate your rig so you could correlate the resistance of the thermistor to a body temperature.
But if you only want to observe a change and you’re confident that you can do a baseline measurement without a fever, you might be able to get away without calibrating. You’d likely be able to tell you had a fever, but not whether it was 99.5° F or 105° F.
I’m not sure that’s a lot better than no thermometer at all, but there you go.
Skin temperature is going to vary pretty widely (Wikipedia says 33.5-36.9 for basic skin temperature), so you are going to want to “stick it” in the mouth, armpit, or rectum. (The “normal” reading will depend on where you measure; axillary will be cooler than oral.)
Obviously the probe should be secure and covered properly with a disposable cover or cleanable cover. You will not be sticking loose, sharp wires anywhere. Also calibrated.
Another option is temporarily to use an old mercury or other glass thermometer. Just don’t drop it. We have also seen those people using infrared thermometers at airports, supermarkets, etc., but I am not sure how to use them for medical purposes besides obviously measuring skin temperature.
I work for a company that makes those infrared thermometers. IMNSHO, they’re irrelevant to COVID-19. The incubation period is so long (3-14 days, I believe) and there are so many asymptomatic carriers that checking for fevers in crowds is (health) security theater.
Plus, the skin of people of East African heritage will generally have very different emissivity than will the skin of someone from Lapland. The emissivity variable makes it really hard to judge absolute temperatures, even with a calibrated IR sensor.
Hi, sorry to take so long getting back to this. Armpit occurred to me an hour after posting, and on the first try I got exactly 37 °C so I felt pretty foolish. Since then, I’ve got some mixed results and the multimeter only reports to a full degree. However, three hours after I posted, the thermometers I ordered a month ago showed up in the mail. :smack:
Miscellany:
[ol]
[li]If I’d had a glass thermometer or could have got one, I would’ve used that. The fear of dropping it wouldn’t have deterred me. [/li]
[li]The “stiff wire” of the multimeter’s temperature probe isn’t really that bad. It’s sheathed with plastic with just the tip exposed and that has a sort of ball at the end, so it’s not sharp or “pokey”. I’m not saying I’m going to use it rectally or even orally, but axillary (love that word) use is not a problem.[/li]
[li]Yes, digital thermometers must use thermistors. I see that now. I’m learning basic hobbyist electronics while sheltering-at-home and the thermistor lesson ended with a sort of epiphany that led to the OP. [/li]
[li]Multimeters are wicked cool. Everyone should get one![/li][/ol]
There’s obviously significant variation in visible-light emissivity, but is there really any significant amount of variation in the far infrared? I’d expect that we’re all pretty close to black, in that range.