--- 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.

                                                                 [Arduino case]

Now, I can keep all my Arduino equipment in a case that I can keep in my backpack, or on me.

                                                                    [Arduino rig]

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...

https://www.sparkfun.com

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.

--- Useful things ---

2016

An advantage of walking is that you only need what you can carry, or, put another way, you only carry what you can carry. My years as a backpacker comes in handy. It's surprising how much you learn when you have to worry about size and weight.

I find that I don't have to worry too much. In the first place, I'm at that age where I can wear just about anything I want without drawing attention ("When I'm old, I shall wear purple...."). My main consideration is that I'm in Colorado which is a meteorologist's nightmare. I walked to the shopping center (less than a mile) a couple of days ago. When I left, it was warm and fair. I was chased home by a thunderstorm. That night, some folks around here was coerced into wearing sleeves. From September to June, if I go on a long hike, I have to plan to remove layers as the day goes on, and I'm never sure if I will need to. Luckily, I get hot in the upper 50s when I'm active.

It's been below freezing here and I've always worn overalls and coveralls hiking. A flannel shirt, sweater, and leather coat is the most I've ever needed for warmth. You, of course, need to plan for your weather and your body heat.

I wear regular clothes and inexpensive shoes. Socks make a difference. Shelling out for the microfibre wool and such is worthwhile if you don't like blisters and such, but I go the way of the bandaid and moleskin when I feel a hotspot developing. I've had a lifelong relationship with pain and it doesn't bother me much. Pain avoidance, I find, is a individualistic thing.

I have caps for short hikes and big, floppy expedition hats for long hikes. I've had cataracts removed from both eyes and Colorado's sun is not the same sun I knew in Alabama. It's closer and less filtered. I try to keep the sun out of my eyes and I find most sunglasses to be ineffective.

Secondly, hiking requires something to carry everything in. I'm a Rob Liefeld hiker. I like pockets and lots of them, which is one thing that draws me to overalls. I hate digging through a backpack to find a piece of equipment.

I have two backpacks, one for short, nontechnical hikes and just walking to the store - the other for long, technical hikes and for hauling back 60 pounds of groceries from the store.

I'll be distinguishing between technical hikes and nontechnical hikes. Technical hikes are project oriented, requires equipment, and usually involves the collection of quantitative data. Nontechnical hikes are more casual, requires little equipment, and usually involves observation.

My big backpack can handle a laptop and I have several laptop size inserts with pockets and straps, that can be used to outfit myself with a portable laboratory. American Science and Surplus (bless their little bitty comedic hearts) often carry those kinds of things at prices that a retiree can handle.

I also keep a couple of waist packs (or "fanny packs", if you must) for my photographic material. One of those I almost never carry on hikes because it carries equipment for the SLRD camera, which I only use for portrait photography. I would not want to have to carry that huge thing on a hike (although I wouldn't mind driving up to a ridge one afternoon with it.)

I carry two cameras. I use my regular digital camera for most of my photography. That saves batteries for my phone. That,  I use for much more than photographs. My phone camera is used for closeups, telephotos, and microphotos. It's much better and has much better stabilization than my regular camera.

The phone also carries a library of apps, guidebooks and maps that I use for technical hikes.

I like to be a model of what people on a limited income can do to enjoy their world so I try to avoid expensive equipment and activities. My most expensive piece of equipment is my laptop which, admittedly, is a little pricey, although not nearly so much as when I bought it. But I assume that, if you're reading this, you have access to a computer anyway. My computer is my home lab. I have many pieces of equipment that plugs into the USB port, things that, a few years ago, would have cost a laboratory enough that they would have to save up awhile to buy it. For instance, you can now buy a spectroscope for a computer or smartphone for less than ten dollars.

According to where you live, rain gear is important. In Colorado, definitely. In the southeast, it's a sometimes thing. And in Arizona, do you ever need it? A good, light rain jacket is inexpensive and easy to pack. I've never had any need at all for rain pants. As long as my shoes are relatively waterproof, I'm happy. Actually, I don't mind rain or being wet as long as I'm not also cold. Years working outside in the rain has made me rather blase about most weather conditions.

Werewolves don't get sick easily and heal quickly, but I carry a small first aid kit anyway, mostly for blisters. Plantar blisters plague me and I can slap a bandaid of swatch of moleskin on one and I'm good to go. I carry only what I think I might use. If I get a cut, I'll wipe it off with a moist towelette and smear on some Neosporin. I don't even cover it. If It's bleeding, I let it bleed. There's no better antiseptic/antibiotic in the world than blood. On long hikes, I carry suntan lotion (the spray on greaseless kind) because I'm light skinned and tend to burn easily, and I carry bug spray because biting insects find me tasty.

If I'm gone long, I carry a roll of toilet paper. There are many rest stops on Bear Creek - other places, maybe not so much.

I've taken to wearing a biker's mirror on my glasses, not so much for the bikers; in my area, they're very polite and warn you when they're coming up behind you, but for stalkers. We have a few furry ones who are not very much trouble but, I would want a photo. Briefly, I'm out there to observe my world and I want as much coverage as I can get.

Other than that, I choose the equipment I will need for the project I have at hand. I choose inexpensive and compact tools and I pack so that I can get to what I want when I want it.

Uh, I almost forgot one of the most important pieces of hiking equipment. I always carry an old, worn t-shirt tucked into my back pocket. I sweat a lot and that works much better than a handkerchief to keep the sweat out of my eyes. I can also twist it between the sleeves, flip it over my head so the tail falls over the back of my neck, and tie the twisted part around my forehead for a quick do-rag.