extended reality at 78°

 Many of you spend a lot of time traveling around the world.  While the act of travel can be frustrating, new places, people and experiences dramatically richen our lives.  But this usually only makes use of our normal everyday senses.  We're missing so much. Human vision is only a tiny window into the electromagnetic spectrum that surrounds us.  The same for hearing.  And we only experience narrow time.   Events can be too fast or slow for us to notice - global warming for example.   Size is a problem - we can't see the small and only see tiny bits of the large.  And the version of reality our brain assembles goes through a lot of filtering and computation.  

 

Not that this is bad.  The richness of the bit of Nature we perceive wobbles the mind.  And our species is clever enough that we've learned to extend our senses and find new beauty everywhere.   Even the world near your home can be as exotic as any place you can travel on the planet.  You just need to be a bit curious.

 

I live next to a large piece of swampy lowland with terrible drainage.  It's classified as a wetland with development not be allowed this century.  Working out of the home for the past 15 years I've come to know it.  I make a point to spend at least an hour walking in the woods around noon every day no matter the weather.¹  You develop a sense for what a season means.  I've learned we have six distinct periods rather than four.   You keep a diary and make drawings.  With time longer term signals begin to emerge ..  patterns different from seasons. You begin to experience longer time.  

 

My iPhone has become a tool that allows a bit of time compression and expansion.  Nothing dramatic, but much better than what my brain does and worth playing with if you have some patience, a tripod and an app or two.  You can hack that old digital camera and make it sensitive only to infrared light.  Or load that old film camera with film sensitive to the near ultraviolet and find out that humans have stripped patterns on their skin.²   UV is a fun way to look at flowers.  Some pollinating insects are attracted to UV and many flowers have hidden patterns to attract them.  I had a discussion with a gardener who was planning a public garden with a design that would be apparent only if you looked at it in the ultraviolet. 

 

A field microscope is an amazing, to paraphrase Steve Jobs, vehicle for the mind.  Rich enough that I need to write about it separately.  Using your smartphone to record and process the images makes them even more powerful.  

 

The same for sound - your smartphone is a powerful computer with a microphone and a display.   I'm doing that just now.  You've probably heard that the rate of cricket chirping changes with temperature.  This time of year the woods are thick with crickets - four species at least.  They can't chirp if it's cooler than about 55°, but the relationship between chirp rate and temperature is nearly linear from 60° to 95°.³  The standard method is to count how many chirps you hear in 15 seconds.  Make a number of measurements - ten is a good start - and take the average.  Add it to 40 and you should be close to the temperature in Fahrenheit.

 

Being simultaneously lazy and ambitious  I wrote a little program that uses the microphone on my MacBook, does a bit of computation, and shows a spectrogram.  Time is displayed on the horizontal axis, frequency vertically.  Loudness is color coded.  This is thirty seconds with the window closest to the woods open.  There are a number of spectrogram apps for smartphones - I haven't played with any, but you should be able to "see" acoustic detail around you to at least this detail.  If you're really serious write and I'll point you towards some serious proam scientific software. 

 

Notice there's a lot of low frequency noise - something to investigate, but later.  The cricket chirps splash across a number of frequencies, but there's a lot of energy around six kilohertz.  In 15 seconds I count 37.  Doing this a dozen times I average 37.3.  I took a thermometer into the woods a few minutes ago and read 78°F..  40 + 37.3 isn't too bad. 

 

There are a lot of interesting bits of biology and social insect behavior going on that prevent the relationship from being very accurate.  This measurement was a bit lucky.  I've done it at a variety of temperatures and two degrees from the thermometer is more common.  If you can identify different species it might be fun to plot air temperature vs chirp frequency for a range of temperatures and see how it varies from species to species.  

 

There's a lot of richness in the signal to investigate - intensity for example.  Even an amateur can learn a lot and amateurs can make an impact in this type of field biology.  A few years ago I saved a link to a WBUR On Point interview on crickets... it's about a half hour long and just plain fun.  And here's a rich collection of annotated cricket recordings.   Chances are you'll learn something - I did. 

 

The world is much richer than any of us can imagine.  Maybe I'll go into fireflies one of these days.  We have at least four species that you can identify by color, brightness and flash pattern.  It wouldn't be impossible to build an identification app for smartphones.  It shouldn't be too hard and you could even use neural nets to learn about them. 

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¹ ask me about walking in an ice storm - I've found some nice kit.  

² Blaschko's lines. The variations are greater within groups we tend to call a "race" than the visual differences we see between ethnic groups with our eyes.

³ Centigrade is much more common, but in a way Fahrenheit is better here as the degree is smaller.  In physics you rarely use either.