A wristwatch which uses a thermal flux sensor to determine ambient temperature.
Given the normal human body temperature of 98.6 deg. F (~37deg. C) and the intimate proximity of a wristwatch to the body, I'd like to see an outside temperature display on a wristwatch which uses a thermal flux sensor to display whether the outside temperature is lower or greater than body temperature.
This could be much more useful than an outside thermometer, which is often either in the sun or shade, and doesn't accurately show a true temperature near the body.-- csea, Jun 06 2010 Heat Flux Sensor http://en.wikipedia...ki/Heat_flux_sensorI've seen thin sheet material that does this. [csea, Jun 06 2010] [21Quest] Thanks, I did a preliminary search, but the essence of this idea is to use a sensor that determines external temperature by measuring the heat flux to/from one's body.
The "watchwiththermometer" link talks about "self calibrating features on the thermometer", but it's not clear if they do anything besides measuring the external case temperature.
Thermal flux sensors actually measure the energy transfer vector, which should give a more accurate idea of whether the local environment is heating or cooling one's elf.-- csea, Jun 06 2010 The //normal human body temperature// is an average for core temps. I don't know how much the variance is out at the limbs' distal ends, but I know I can't hold a thermometer in my hand and get it above 90 F. So your "fixed" temp side probably isn't more stable than the measurement errors you're trying to overcome.-- lurch, Jun 06 2010 Nice idea,[csea],but you are going to struggle to overcome the issues of dry bulb temperature variance against moisture content of the air. The transfer vector will be affected due to latent cooling via evaporation,no?-- gnomethang, Jun 06 2010 Good points, all. I suppose one could affix thermal flux sensors over a wider range of body parts and connect them all up with bluetooth, etc., etc., but that might be overkill.
Maybe what I'm after is a measure of "how hot or cold does it feel?" i.e. how fast is my body losing heat, including perspiration and humidity effects.
Hmm, back to the drawing board...
Nice BTTF ref, [IT].-- csea, Jun 06 2010 random, halfbakery