Is there some kind of infrared thermometer someone could buy for themselves and detect a sickness early and minimize the transmission by voluntarily isolate themselves for a moment?
First, the fever and temperature increase come after 2 to 5 days of infection (14 at most). So you are effectively contagious before showing any symptoms. This is why most detection measures at airports are useless. It used to work for other outbreaks though (e.g. SARS/MERS).
Second, realistically most people would not want to isolate themselves. They will want to leave China and find a hospital in a neighboring country where they could be treated in better conditions (e.g less overcrowded hospitals, more staff). This is why a lot of Chinese people try to cross to Hong Kong or still attempt to fly to Europe even though they know they are sick.
Last, some people will just ignore the fever and hope for the best. We have seen people arriving in HK from China and straight refusing to be tested for the virus.
I’m not blaming anyone here of course. I don’t think this is intrinsic to the Chinese mentality, most humans would do the same in such conditions: unconsciously ignore the symptoms, refusing the rational solution and putting themselves before the risk to others; because faced with the probability of dying, your brain can make you believe anything, even that your fever will vanish.
There is an instrument called an infrared thermometer. It measures the long-wave radiation emitted from a target object and computes it's temperature.
However that will only give you the measure of a single spot, which could be inaccurate due to thermal reflections, or noise, so ideally you'd want an infrared camera, which will provide a thermal image your target. They're a bit pricey though.
On the other hand, why not just use a regular thermometer?
It’s possible to remove the infrared filter from a normal camera and replace with one that only lets in IR. lots of articles online but no idea how hard it is.
The Whoop[1] does not measure body temperature but it does measure your heart. Several users claim it has detected their sickness before they realize. FitBit too.
There are too many confounding factors for resting heart rate to be a reliable measure of illness - stress, dehydration, a hot climate, alcohol and lack of sleep can all have an impact.
