Thursday, March 21, 2019
--- The police ---
"To Protect and to Serve" was the motto of the Los Angeles Police Force since 1963 and it has been adopted by many other police forces since then. Many police officers take an oath to protect and serve, but don't let that fool you. That is not their purpose - hopefully it does end up including that, though.
In America, the purpose of police (and that includes organizations such as the FBI, CIA, and other government alphabet soups, and the Armed Forces) is to uphold the Constitution. That's right, they're part of the executive branch of our government. In fact, they're the front line.
Do you think you've been fed a line? Okay, here's where it all ties in - the Constitution is the document that was written to serve and protect the people of the United States.
"We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defense, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America."
And, yes, it does go wrong sometimes, because, just like the courts have to interpret the Constitution to make decisions, so do police.
After the equivalent of a minor in criminal justice (my university wouldn't let me claim it since I already had three minors) and involvement with some of the training programs in Alabama, I have to say that I'm impressed with what I've seen. Of course, what people learn in school and training programs often become modified when they emerge into the "real world".
Actually, it would be hard to talk about my experience with police forces in the South and in Denver because I don't talk about individuals in this blog without their express permission, but most of my interactions have been very positive. You can form your own opinions. Here are some research methods.
Wave at police. Be friendly about it. I wave at people who work for the community, partially to show them the respect they deserve and partially to open them up to communication - body language, y'know. Many community servants - bus drivers, trash collectors, road workers - appreciate the recognition....and some don't. It can give you some idea of how community servants feel about the people they serve.
Which brings me to the other research method. There are many opportunities to form connections - positive connections - with police. They come to community events - go meet them. And although I haven't been able to find a Citizen's Patrol in the Denver area, many of the police departments (maybe all?) have Citizens Academies. They are seven week long courses on important neighborhood issues including security and police procedures.
My impression (and some research) is that the more positive connections there are between police and citizens, the happier citizens are with their police departments and the smoother police work goes.
Sounds like fun but, as a pedestrian, there's not a citizen's academy close enough for a night walk two or three times a week for seven weeks. But if you've attended, let me know how it went. Leave a comment...and a discussion!
Tuesday, March 19, 2019
--- Buddhism in Denver ---
It's not surprising, given the Asian populations in Denver, that there are many, and a great diversity, of Buddhist churches. I believe I've found all the denominations I know about within the Denver area.
Most of my Christian friends have been adamant that Christians should avoid nonChristian religions. Yoga was verboten since it smacked of Hindu. But, then, that doesn't go very far in explaining why Paul quoted nonChristian philosophers in his letters (I Cor. 15:33 and Titus 1:12) and in Acts 17:28.
I find three Christian Buddhist churches in the Denver area (http://www.mayusanctuary.com/index.cfm/id/26/Denver-Centers): Contemplative Outreach of Colorado, Loretto Spirituality Center, and Montview Boulevard Presbyterian Church. Looking at the Loretto site, it might be more accurate to call their form of Christianity "contemplative Christianity" and leave the "Buddhist" tag off. I find the Buddhist message, to live a non-grasping lifestyle, to be a needed anodyne for modern Christianity.
I set off early March to check out the small Buddhist temple just off Estes Street. The people I met spoke only a little English and with difficulty but they were friendly. I did gather that there was a monastic community in the Denver area.
[Buddhist Association of Colorado 030817]
On 7/20/18, I hiked over to the Ross-University Hills Branch of the Denver Public Library where they were having a program on Buddhism. The program was put on by a local organization called Active Minds and I applaud the library and Active Minds for presenting informative, educational presentations to the community.
The presentation was quite introductory, but enjoyable for me in that the presenter had traveled in areas of the world where Buddhism is a majority religion, and he shared personal anecdotes. He also included contemporary issues, such as the awkward interactions between various forms of Buddhism, the Chinese government, and Muslim communities. I had not heard that the Dali Lama has decided that he may not reincarnate this time. That may not mean much to Christian and secular populations in the West but it could be earthshaking for adherents of Tibetan Buddhism - which could turn into something that is simply earthshaking.
Ripples of causation - that's karma and we have to deal with it regardless of what our religion is.
The Domo Japanese Restaurant is a mixed adventure. I ate there on my hike from Auraria West Station to 10th Street and Osage Station. The raman dish was large and full of many interesting thinks. I'm sure I saw dicon radish and chicken but I'm not sure what the rest were. As for the three sides, I didn't ask questions and thoroughly enjoyed my lunch. Afterward, I wandered through the garden. There were several shrines there. I saw several offerings placed before the statues of Buddha, so they can certainly be seen as places of worship.
Perhaps the outreach ministries they support for refuges from Myamar should be considered acts of worship, also. Collection boxes for the Akido Humanitarian Active Network were located in close proximity to the shrines.
You may be interested in checking out the Domo's websites.
There are several Buddhist cultural centers in Denver, in addition to the Domo Restaurant. See my blog: A Trip to Asia for my account of a visit to Little Saigon.
Also see the blog: Terminus: Union Station for a description of Sakura Square.
Are any of your neighbors Buddhist? If so, they don't proselytize but most of the Buddhists I have known have been happy to talk about it. Perhaps there is even some public Buddhist art in your area or a lecture you can attend. Other religions are part of your world and, since they certainly affect you, often without you even knowing, it's a good thing to be interested.
Monday, March 18, 2019
--- The Highline Canal: Complexity ---
Here are several sources of information about the Highline Canal.
One thing you will notice right off is how the canal meanders across the countryside for 71 miles.
Actually, that is not exactly correct. Rivers meander - the canal does...something else.
The reason a stream meanders is that various factors pull it in different directions - the same kind of factors that makes a thin stream of water meander across a gently sloping pane of glass. The glass isn't perfectly smooth so the stream has to flow around the tiny imperfections. Also, the earth is rotating out from under the water as it flows, creating the Coriolis effect.
The South Platte River shows this kind of meandering as it flows through it's valley near Denver and, even more as it flows out onto the plains.
The Highline Canal is very convoluted for another reason. It follows the topographic contours of the eastern rim of the valley cut by the South Platte River. It flows by gravity so it's gradient must always be down and the Highline flows downhill at a gradual 2 feet every mile. If you've ever looked at a topographical map, you know that it's rare that a contour ever follows a straight line.
By the way, THE Highline Canal is not the only highline canal in the Denver area. There is also the Farmer's Highline Canal that flows through Golden to Westminster and Thornton. There are also several other highline canals in Colorado and, certainly, many in the world. A highline canal is simply a canal the follows a topographical high line (contour).
The highline canal, at a stretch, could be called fractal. That would not be completely accurate because fractility implies repetition at different scales. If you magnify a design and it looks the same at each magnification, that would be fractility. The classic example is the Mandelbrot set.
In physics, scale is capped by the size of the universe at the top and quantum "graininess" at the bottom. There are no such limits in mathematics. You can always come up with a smaller number. So when I say that the Mandelbrot set has infinite detail, I mean it. You can keep magnifying the Mandelbrot set for ever and you will still discover more detail.
Check out this series of magnifications of the Mandelbrot set.
That last one....is that a tiny Mandelbrot set that I see? Why, yes...I believe it is!
There are, in fact, an infinite number of Mandelbrot sets embedded in any Mandelbrot set. There are also other designs like this one.
[Detail from the Mandelbrot set]
A shocking detail is how the Mandelbrot set is generated. It grows from this simple equation.
[Equation for the Mandelbrot set]
This equation tells you to set c to some complex value and then calculate the result of the equation when z is 0+0i. Next place the result back into the equation as the new value of z and keep doing that.
Some values of c, for instance c=0+0i, just sits there quietly. In the case of 0+0i, each step just returns 0+0i. For some values, like 0.804608667883013+0.820834819347395i, the equation "explodes" on the 11th step and my spreadsheet can't even calculate the 12th step because the result is too large. On the other hand, 0.107533656386414+0.479408179270122i shows no sign of getting out of hand through 25 steps.
To create the Mandelbrot set, you just do that for every value of the complex plane and, if a point "explodes", graph it. You can use different colors to indicate how quickly it explodes. The points that don't explode are members of the Mandelbrot set.
If you look at a map of the Highline Canal, a mile long section doesn't look like a 10 mile long section and there doesn't seem to be a copy of the whole canal hidden within a shorter segment, so it would be a stretch to call it "fractal". But is complexity conserved at different scales? In other words, is a 5 mile segment just as wiggly as a 20 mile segment?
Obviously, this could only go so far. A 5 foot section of the canal is not complex at all - it would look straight! But what about "reasonable" lengths - something you could see on a map.
There are measures of complexity that require a computer and a very complex equation to calculate - I wanted something a little simpler. I decided to use a measure that compares the "hiking distance" of a section with a "as the crow flies" section. The Highline Canal trail has been measured - I'm going to assume that the trail mileposts were set up according to hikers with pedometers, but I don't know. I can determine straight line distances using the Google Maps measuring utility.
Now for the comparisons. It would be easy enough to just subtract the straight line distance from the much longer hiker's distance, but then I couldn't compare a 5 mile section with a 10 mile section. I needed a standardized measure. A ratio would do the trick so I used the ratio of the hiker's distance to the straight line distance.
Ratios are dimensionless. As a fraction, if the numerator and denominator units of a ratio are the same, they cancel out. That's good for my purposes because, a ratio of two measurements will be the same whether the units are feet, miles, or kilometers. They aren't dependent on scale.
My measurements are in miles, to the nearest mile. I'm taking measurements off maps that show the positions of trail mileposts so I can't be more accurate than a half mile; therefore, I round map distances to the nearest mile and I can't do any better than that in calculations. That's okay. It's good enough for my purposes.
I have a ratio for the entire trail, four for the quarters that I'll be walking this year, and 15 for the roughly 5 mile segments shown in the Highland Canal Conservancy maps. I've also calculated the arithmetic and geometric means and standard deviations for the quarters and segments, and I have a histogram for the ratios for the segments.
The reason for the histogram is that, if the distribution of the ratios looks close to normal (which it probably is not), I can put some stock in the statistics I've calculated. Luckily, the histogram shows a curve that could be mistaken for normal - it's probably binomial but I'll ignore that.
The Highline Canal is 71 miles long, walking distance. As the crow flies, it's only 30 miles long. The ratio is about 2. How similar are segments of the trail at different scales?
The quarter ratios range from 2 to 3 for an average of 2 and a very similar geometric average. The calculated standard deviation is about 0.4. Smaller standard deviations mean less variation. If you select a 20 mile segment of the canal trail, there is a 68% chance that it's ratio will be within 0.4 of the average: somewhere between 1.9 and 2.7.
The 5 mile segments look very similar in terms of complexity. The average and geometric average ratio is close to 2 which is well within the expected complexity of the quarter sections and not far off from the ratio for the whole trail. The standard deviation is about 0.7 - more variation than what is seen in the quarter sections, but still not a lot.
What all these numbers mean is that, in terms of how much the canal and it's trail meanders, 5 mile segments look a lot like 20 mile sections, and the 20 mile sections look a lot like the whole trail.
If you walk the trail, you'll see what I mean. You can see that it's very "wiggly" from the maps. There are places that you can walk 10 minutes and you find yourself very close to where you were 10 minutes ago.
Some parks have very convoluted walking trails simply to pack longer trails in smaller areas. Complexity can be useful. The Highline canal is convoluted so that it can follow the terrain with a constant, very shallow down-hill gradient.
On a surface more complexity provides more surface area. Your small intestine membranes are very complex, packed with tiny fingers jutting into the inner space of your gut. They increase the surface area of the membrane that absorbs nutrients from your food. Chemical engineers who design catalysts for things like catalytic converters and chemical reactors want the catalysts to have as much surface area as possible so that as much of the reactants can get to the catalyst as possible.
If the Mandelbrot set could be translated into a physical object, it would have infinite surface area and would make a great catalytic surface or absorber. Of course, it can't, but you can see why fractal surfaces can be useful.
If you would like to explore fractals, there are many Mandelbrot viewers on line such as the one at:
or you can download the Mandelbrot explorer at
There are many examples of fractals in nature. The way limbs split off a larger limb looks a lot like the way the larger limbs split off even larger limbs, and the way vein in leaves divide. Smaller sections of the swirl of sunflower seeds look like the whole swirl. The next time you walk, look for fractals on the trail. You might be surprised at how common these intricate patterns are.
Sunday, March 10, 2019
--- Language for it's own sake ---
Humans are just about the noisiest animals on Earth. Noise is not a good survival technique and the only time wild animals are noisy is when they have no major predator (elephants are big enough that they can do pretty much whatever they want), when they are in a big group, or when they are looking for a mate. Evidently sex is important enough to risk their life for.
Coyotes can be noisy. They use it as a defense. Three coyotes can sound like twenty. There was a pack of coyotes near where the Boy Scouts camped in Dallas County, Alabama. I once asked another pack leader how many he thought were in the pack. His guess was way too large. The trick is to count the different voices. Canids do not harmonize. The howls are a form of communication and it's important that each member of the pack can be distinguished so they howl on discordant notes. If two wild canids blend, they will quickly change their tones to a discord.
Go to a park on a sunny warm weekend when children are playing there. Usually that noise is irritating to adults and they try to filter it out, but just sit and listen. Identify the different sounds and patterns. Much of what you hear will have nothing to do with speech and a lot of it will be really hard to even connect with any kind of communication.
Children play with their vocalizations. They experiment to see how many different sounds they can make and, when they find one they have never heard before they are delighted and make it ad nauseum.
Many nonverbal vocalizations are communications. A groan can communicate pain, a sigh, contentment or futility. But by adulthood, humans have begun avoiding nonverbal communications. For better or worse, there is a cultural distancing from "the animal".
There are several modern composers that have capitalized on the human voice as a musical instrument. If you're interested in this, check out the following pieces:
Luciano Berio - Sinfonia
Phillip Glass - Einstein on the Beach
Gyogy Ligeti - Atmospheres, Requiem for Soprano, Mezzo-soprano, Two Mixed Choirs, and Orchestra, and Lux Aeterna (all these are in the 2001: A Space Odyssey soundtrack)
I was listening to Einstein on the Beach and a local TV personalities name popped out. The "lyrics" contained a television schedule.
You may not like this music - it's not everyone's cup of tea but at the very least, it's interesting.
Friday, March 8, 2019
--- The courts ---
There is a fractility in the United States government. What I mean by "fractility" (and I will be talking much more about that as time goes on, because it is one of the characteristics of complexity) is that patterns on one level are repeated on other levels. This patterning allows a balance of powers, the pattern is three-fold and the three parts are set against each other (if things work right). Any one of the three parts can stymie either of the other two parts if it really wants to. The founders of American government quite consciously and intentionally crippled the government.
Why? Because they didn't trust government.
We had had quite enough of government control in the form of the English monarchy. But the founders realized that we had to have some form - some degree - of government - sort of a "can't live with it and can't live without it" attitude.
So we have three parts of federal government and that three-fold pattern is repeated at the state level, and the county level, and the city level, and often at levels between and possibly at the neighborhood level and in organizations.
Executive - legislative - judicial. Those are the three branches of government in the United States. The legislative branch makes the laws, the executive executes them, and the judicial interprets them.
If you want to see an instance that breaks the three-fold pattern, check out Louisiana.
I visited the site of the headquarters of the first two branches of government in Colorado in January. It's the capitol. Both the governor, the head of the executive branch, and the legislative branch are housed there. The other branch is more complicated and is scattered around all over the city and, indeed, across the state. But the highest level of the judicial branch is located just across Civic Center Park from the Capitol in the Ralph L. Carr Colorado Judicial Center located at 2 E. 14th Avenue, Denver, Colorado near Broadway. This is the highest court of appeals in the state of Colorado. If you have a problem that you need to carry to court, you start at the bottom and if you don't like the result and you can convince a higher court that the lower court made a mistake, you get to move up the chain. The Supreme Court housed in the Ralph L. Carr Building is the end of the line - the highest state court. From there, if it's actually a federal issue, you might be able to jump to the federal supreme court in Washington, D.C., but that's a little far for me to walk so, on the 26th of February, I visited the Ralph L. Carr Building, and monumental structure, more modern, but, in many ways, just as spectacular as the Capitol across the street.
I took the light rail from University Station to the Convention Center Station and walked down the 16th Street Mall to Civic Center Park around which much of Colorado government takes place. I guess I could have taken the Mall Flier Bus the few blocks down to Lincoln or Broadway, I enjoy the walk through downtown.
Walking around the perimeter of Civic Center Park carried me by the monumental City and County Government Building that encloses the park, with the Capitol like a set of parentheses. The curve of the facade and the ornate columns match the classical style of many of the other buildings around the park.
The Denver Public Library is just to the east of the Ralph Carr building with its disparate jumble of sections looking much like a modernized castle. To the south are the art museum and History Colorado museum. You could spend a couple of days just looking around this area.
[Denver Public Library]
The Ralph L. Carr Building as a modern counterpart to the stately classical style building around it. There are columns and a rotunda but the columns are square and the rotunda is glass.
[Ralph L. Carr Building]
If you've followed me in this blog, you've heard of Ralph Carr. His statue is at Sakura Square to commemorate the governor who bucked public opinion to speak out against the treatment of Japanese Americans during and after World War II.
The interior is beautifully adorned with modernist murals and the floor of the rotunda is decorated with a stylistic columbine blossom.
[Interior of the Ralph Carr Building]
The learning center is just off the main lobby on the first floor. Although photographs would not convey much about the room, if you want to know about the legal process in the United States and Colorado, visit it. This is your complete and fun education of the judicial system. Interactive exhibits let you experience the parts of judges and lawyers. The history of the courts is laid out on columns. And, if that's not enough, plan your visit so you can sit in on a deliberation of the court.
The website is here:
And, like legislative sessions, you can find recordings of supreme court deliberations on the website.
In the United States, it's too strong to say that you are controlled by your government (still, if you don't understand how the government works, there's a good chance that you are controlled), but you are regulated. That's not necessarily a bad thing, but does it really make sense to be regulated and not know how you're regulated? In the United States, the courts, legislature and executive branch are transparent. If you want to know how they work, you have every opportunity to do so. If the wool is being pulled over your eyes (so to speak) it's because someone walked up to you and said, "This is wool. I'm going to put it over your eyes and while you can't see, I'm going to do things....you might not like it." Sooooo.....one of the things that every citizen of a country should make it a point to know is how their country works.
A visit to your country's, state's, county's, city's seat of government is fascinating and fun and what you learn there might or might not change your life, but it will certainly help you avoid wool.
Monday, March 4, 2019
--- Highline Canal: Winter ---
Before I even get started, let me warn any through hikers on the Highline Canal Trail that there is currently no easy way around Plum Creek on the trail. You can walk a long way up Titan Road and north on Santa Fe, both heavily trafficked much of the day with little shoulder to walk on, or you can walk across the entire width of Chatfield Lake State Park, a large and hilly expanse, to Mineral Road and take the Mineral Trail up to reconnect the the Highline Canal. As detours, I wouldn't recommend either although Chatfield State Park and the little parks along the South Platte River are at least scenic.
I took a Lyft to the Colorado Trail trailhead Thursday, February 28 with the intention of walking 18 miles to the Elati Street trailhead of the Highline Canal, but, as the very nature of adventures is to throw curve balls, I only made it seven or eight miles (maybe further after wandering around looking for a way around Plum Creek). I did, nevertheless, enjoy the hike. I realize that the Rolling Stones were correct - "You can't always get what you want."
Expecting a long walk well into the night, I got up at 6:00 and was out as the sun was rising.
By the time I reached the trailhead across from the Kassler Center in bright daylight. The foothills were gorgeously speckled with patches of snow from the big snowfall the weekend before.
[Kassler Center at Waterton]
My plans required a short roadwalk south along Waterton Road to the canal. The Lockheed-Martin plant is ever visible through the first stretch of the trail to Plum Creek.
It doesn't snow constantly in Denver during winter but it does enough that there is usually snow on the ground. This is probably a pretty typical view of the South Platte in the winter.
[South Platte at Waterton Road]
There is a reservoir, the Platte Canyon Reservoir, at the Waterton Road Trailhead that draws water off the canal for storage. It seems to be popular for water birds. I hope these like the ice.
[Platte Canyon Reservoir pumping station]
[Lockheed Martin, again]
[Platte Canyon Reservoir]
[Birds - look like gulls to me, there were also ducks but they were too far out for a photograph]
The first few hundred meters of trail were paved and the canal was dry except for stretches that ran with snow melt.
[Snow on the trail]
I saw a lot of this rosy leafed plant on the side of the trail. I'm pretty sure that it would have been green during the summer and I'm not sure what it is - maybe a potentilla? I thought it was a red moss at first. Out of all the wildflowers, I think I like the belly flowers most. Those are the ones you have to get down on your belly to see. They are often some of the most intricate, colorful blooms. I'd like to see what the flowers on these look like.
Much of the Highline Trail in this area runs through private properties. There are a lot of horses and cattle.
This ranch has a log cabin on its grounds.
And, here, the canal actually looks like a canal with snow melt.
The power lines that cross the Highline Canal carry lots of juice to Lockheed-Martin which could be considered the gateway to space, since they build rockets. Denver is very space conscious. The School of Mining in Golden has begun a focus on technology to mine asteroids, for instance.
The trail along the boundaries of Chatfield Lake State Park affords great views of the Front Range. The hills in the foreground hide Conifer and the one in the middle distance is Mount Morrison. Further back is the mountains around Golden and Green Mountain.
I didn't see a lot of wildlife (or tracks), but I saw or heard many hawks, like this fellow,
and this herd of deer. They seemed to be used to two-legged pedestrians.
This area makes it clear that the high plains butt right up against the Rockies. There's very little transition.
[Plains and mountains]
On the Highline Canal Trail, mileposts are your friend. They appear every mile and mark mileage from the Waterton end of the trail.
My original intention was to follow the Highline Canal Trail to the Plum Creek entrance to Chatfield Lake State Park and pick up the Chatfield Internal Trail in the park which meets back up with the Canal Trail on the other side of Plum Creek. Unfortunately, the construction in the park has obliterated the eastern end of the Internal Trail, so Chatfield was the end of the line for this hike.
The views around the lake are nice (if you don't look in the direction of the construction). The water is down considerably and this is definitely high plains.
As advertised (in the Highline Canal Guide), the Denver skyline is visible from the park but, on this day, there was a gray-brown haze around the city that wasn't very photogenic, so I passed that picture up.
The end of my adventure was a long wait at the parking area at Roxborough Road. I won't go into detail about how my phone's battery died at a crucial point and I had to finagle a way back home, but I will say that the other hikers and the Douglas County Sheriff's Department are great and that Call Box at the parking area? It works.
If you live in the Denver area or will be visiting, you might want to check out the 71 mile long urban Highline Canal trail. The canal is a weird tributary of the South Platte that flows away from the river and crosses roads and other streams. You can check it out on the Internet here:
How's winter in your area? Do you have snow? Are there plants that are especially adapted to your winters? Does the wildlife behave differently?
Saturday, February 23, 2019
--- The Arduino adventure ---
From now on, I'll be doing a lot more technical hikes. I've already done some - the early Bear Creek hikes, where I measured distances and recorded an altitude profile, the smile experiment when I counted how many people smiled back at me when I smiled at them and when I did not smile at them, and the Lookout Mountain hike recording of altitudes, temperatures, and barometric pressures. Beginning with this years explorations of mathematics, I'll be looking at the pure and applied sciences regularly, so I need to make sure that my tools are all in order.
On 1/19/19, I checked the Altitude app (created by Pygdroid and available as an Android app on the Google Play Store) I use to record altitudes and distances to see if I could use it and my camera at the same time. I just wandered around the house with my phone this time and it seemed to work fine but I'll try it later on a walk to the library.
I also checked my Arduino to make sure that it actually works the way I want. I've had it for a couple of years and have not powered it up. I did so today and was happy to see that it works.
I bought my Arduino 101 from SparkFun, a local business that supplies electronic parts, equipment, and kits to hobbyists at great prices. They also offered a plastic carrying case that seemed like a good idea for my adventures. It required a little modifying. The compartments are well divided and I wanted to be able to run wires between them, so I cut some notches into the dividers.
Now, I can keep all my Arduino equipment in a case that I can keep in my backpack, or on me.
I also bought a plastic cover for the microcomputer. It fits nicely into a smart phone holder that will attach to a camera tripod. I will be making one more alteration of the Arduino case - a bolt in one compartment that I can screw the clip to. That should keep my equipment from moving around in the case while I'm hiking.
[Arduino and clip]
When I attached the microcomputer to a 9 volt battery, it lit up.
[Arduino powered up]
and when I opened up my Science Journal app and looked around for the Bluetooth, I found this screen...
[Arduino on Science Journal]
I am set.
It's sorta frustrating that it wouldn't do you much good for me to go into a lot of depth about using the Arduino 101 since, soon after I bought it, Intel, it's manufacturer, decided that they didn't want to be in the microprocessor business and the Arduino 101, which is set up from the get-go to work with Science Journal, is no longer available.
The good news is that, if you want to play around with a microcomputer on the trail, SparkFun has other Arduino (and other microcomputer) options with Bluetooth.
If you want to check out SparkFun (and I highly recommend them), here is the address of their website...
I then went about testing to make sure that my Arduino would accept external inputs. Here's a photo of my setup.
[Arduino with photocell]
There are two items on my plugboard. Right on the gutter in the middle is a photocell. Just to the right is a resistor. An electronics hobbyist would immediately recognize this as a voltage divider. Let me explain.
Electricity is very much like a fluid. If you have water running through a hose and you narrow the hose (say, by crimping it), two things happen. First, less water gets through. Second, the pressure at the end of the crimp away from the faucet has less pressure. In other words, pressure is dropped by the crimp.
For electricity, the pressure that drives the electricity is called voltage and it's provided by the source of electricity (battery, generator, etc.). The amount of electricity that flows through the wire over a period of time is called current. The resistor and photocell in this circuit are the crimps. They resist the flow of electricity.
In this circuit, both "crimps" in the line drop a certain amount of pressure. That pressure drop could be measured across either element with a voltmeter. If the two resistors (in a circuit, that's what a crimp is called) have the same value - resistance, the amount the flow of electricity is impeded - then the voltage drop would be the same across each. The voltage would be divided equally between the two. In this circuit, one of the resistors reacts to light. As more light hits the photocell, it resists the flow of electricity more and creates more of a voltage drop. The resulting shared voltage drop across the resistor, then, has to be less. That change can be measured by a voltmeter across either the photocell or the resistor. Here, you can see that I have three wires going to the circuit. The black and green wires run to the Arduino so that it acts as a voltmeter.
The red wire feeds electricity from the Arduino to the circuit through the photocell. The photocell and resistor are connected in series so that all the electricity must run through both to get out through the ground (the black wire). the green wire runs to the voltmeter input to the microprocessor (called an analog input - there are several). So, the Arduino is measuring the voltage drop across the resistor.
The Arduino broadcasts what it measures to my phone via Bluetooth and my Science Journal app records it for me. I waved my finger back and forth across the photocell and this is what Science Journal recorded.
[Science Journal screenshot]
When I placed my finger over the photocell, the voltage decreased and when light hit the photocell, the voltage increased. The values are "raw" because they show voltage level across the resistance (not in volts). The measurement are not in any standard units but, if I knew the relationship between the values and, say, lumens, I could calculate the actual amount of light, but that wasn't my intention.
So, now, I know that I can take the Arduino on the trail with me to measure things I can't measure otherwise with the internal sensors in my phone or another instrument like my weather meter.
Technical hikes involve measurement. There's a lot that you can do with some really inexpensive equipment and learning to use it is a lot of the fun.