Well, I hope this will take care of it for now. I have completed (what I hope is) my final project for my independent studies class in Arduino. The idea behind this project is simple. I wanted to use both a sensor and an actuator of some kind (i.e., both physical input and physical output) and I wanted to use something that could, in a very rudimentary way, lay the groundwork for using Arduino on stage during dance performances as a way of manipulating some aspect of the set. In order to keep things simple and transportable, I decided to use a distance sensor – an Ultrasonic Module HC-SR04 Distance Sensor For Arduino from Amazon, in this case – for input and plain old LED lights as my output.
The sensor reads the distance of objects in front of it and converts those measurements to inches. If the serial monitor in open, the distances are shown, although they jump around a lot. I understand that such fluctuation could be the results of a $5 sensor but could also have to do with fluctuating power supply from my laptop USB. It could also have to do with the actual code that I used, as I decided to forgo the use of a library in this one to keep things simple. Anyway, the measurements are generally accurate. If the object is less than 72″ (6 feet) from the sensor, the green LED lights up. If the object is less than 12″ away, the white LED also lights up. Finally, if the object is less than 4″ from the sensor, then the red LED joins in. Simple but it works.
Okay, chapter 6 of Getting Started with Arduino, “Talking to the Cloud,” has been the bane of my arts technology existence. I did most of this chapter about three weeks ago and couldn’t get it to work. The problem is that the book as a whole seems to progress like this:
Chapter 1: No real information
Chapter 2: A tiny bit of information but no practical work
Chapter 3: A tiny bit more information but still no practical work
Chapter 4: A tiny bit of practical work
Chapter 5: A little bit more practical work
Chapter 6 (this chapter): About 1000% more complicated than all the rest of the book put together
Chapter 7: A tiny bit of information to wrap things up
It really felt like getting thrown into the deep end. However, I finally got it to work. Here is the chronicle of my adventure:
Get intractable errors in Processing because the code was written for v. 1 and we’re now in v. 2
Spend much time searching the web, determine that all of the Java libraries must be installed manually
Get the Processing code running (see first photo above) but get such miserably low numbers for output that no light would be detectable
Revise Processing code to search for more common terms with the hope to being able to see things (see second photo)
With Processing apparently working right, turn to physical components of Arduino
Reconstruct the physical circuit because I took it apart after three weeks (having even schlepped it around with me in a box on the bus and train from Salt Lake City to Orem)
Plug the Arduino board in to my computer
Have the Arduino shut off and get alarming error message from computer (see third photo)
Spend much time fiddling with USB connection, pull out brand new, back-up Arduino board, plug it in and see that it works, recreate circuit on new board, get same problems, notice lots of heat on bottom of first board, think that I have destroyed things, fret much
Search web for help and learn that there may be a short-circuit (without even really knowing what this would mean)
Eventually discover that I put the ground wire on the same positive rail of the breadboard as the power. Oops.
Put the ground wire on the negative rail (the way the illustration told me to do it in the first place), board powers up, problem solved.
Back to Arduino IDE, compile and upload sketch, have lights blink to indicate successful upload, but see nothing happening with LEDs
Mess around with light sensor and the button on the breadboard to no effect
Check the serial monitor in Arduino and see a steady stream of strange data that is absolutely not in the right format
Read book again, see “important message” about serial port selection
Go back to Processing, uncomment code that lists serial port connects and find that my Arduino is connected to port 5 and not the expected port 0
Change port in Processing, rerun sketch, and suddenly see much blinking on Arduino board
LEDs light up! Button turns them on and off! Success! (See last, triumphant photo above)
Okay, that was not fun but I was convinced that I would never make it work so I feel very, very happy now. And I already finished chapter 7 (although I haven’t yet posted it to this web page because I’m an extremely linear guy), so I’ll post this chapter, post that one, and then try to do a small, creative project (which I have been planning – more or less – for a few weeks), and call it quits. But here we go for now!
Getting Started with Arduino, 2e, Ch. 6: Talking to the Cloud (1 exercise – but a really, really big one)
All of this is really used to lay the groundwork for the extended example in Chapter 6. And this is where I have my first movie examples to show things changing gradually. (Always glad to have the iPhone handy….)
Getting Started with Arduino, 2e, Ch. 5: Advanced Input and Output (5 exercises)
Understanding. That is, it is very helpful if you understand how all the parts in your project function and how they contribute to the intended final product.
Simplification and segmentation. Break the project down into smaller pieces and try to check/fix each part separately.
Exclusion andcertainty. Test each part separately and be certain that it works.
The chapter then recommends starting by looking at the Arduino board, then the breadboard, then the Arduino IDE. Also, there are some useful resources available at the Arduino website, but good old Google works well, too.
And, by the way, was able to use essentially all of the principles in trying to sort out several problems with the sketch that I did for chapter 6, so I’m glad for the advice.
Getting Started with Arduino, 2e, Ch. 7: Troubleshooting (0 exercises)
Chapter 4 of Getting Started with Arduino is appropriately entitled “Really Getting Started with Arduino,” because this is the first chapter where we actually start hooking up wires and writing code. The goals of this chapter are relatively simple:
Connect the wires and write the code so the pushbutton can turn on the LED, first as a momentary switch (i.e., the LED only lights up as long as you hold the button) and then as a toggle switch (i.e., click it once to have the LED turn on and stay on, then click it again to have it turn off and stay off)
Simple concept and an excellent introduction to the entire system. I’m much more accustomed to working with Processing and, while the two are very closely related, they’re not identical and the differences are acutely obvious to me. Still, I’m trying to adapt. Some of the differences include:
Explicitly declaring constants
Setting pins as input or output (obviously, this doesn’t happen in the software-only world of Processing)
“digitalRead” and “digitalWrite” as functions (again, because this is hardware now)
The use of “HIGH” and “LOW” as “ON” and “OFF” (I know the latter work but there is a strong institutional preference for the former)
On the other hand, much of the building and troubleshooting procedure is the same: go one tiny step at a time, when something goes wrong, take a closer look at how the machine is making sense of your code, and working through possible solutions one at a time, perhaps through commenting lines in and out. And save versions of your sketch!
So, the fact that I am now able to turn a small light on and off may not seem like much to most people, but it’s a significant journey from the virtual to the physical world for me. Onward and upward!
Getting Started with Arduino, 2e, Ch. 4: Really Getting Started with Arduino (5 exercises)
Prototyping. Making actual, physical objects that do things in the fastest and most efficient way possible.
Tinkering. Playing without a goal, especially with old or broken electronics, is time well spent.
Patching. Making connections between different modules to direct data and control behavior. Robert Moog‘s early analogue synthesizers are mentioned as a prime example. (I like the cover of Switched on Bach in this respect.) Max, Pure Data, and VVVV are all mentioned as programming languages that make patching their primary visual metaphor.
Keyboard Hacks. Sort of the same idea but playing with the insides of a keyboard to make it do different things.
We Love Junk! Because you can take it apart and do things with it. That’s why I haven’t thrown away my old hard drives or mystery power adapters yet.
Hacking Toys. Lots of electronics in kids’ toys to manipulate. The author (Massimo Banzi) recommends the PDF booklet “Low Tech Sensors and Actuators.”
Collaboration. There is, in fact, an Arduino community and they tend to post questions and answers and generally help each other. One interesting place for this is the “Arduino Playground” at playground.arduino.cc.
And that’s it. Of course, any time somebody talks about their “philosophy,” I always think of the choreographer Mark Morris. As the story goes, when he was being interviewed to be the artistic director of the Théâtre Royal de la Monnaie in Brussels, Belgium, he was asked about his philosophy of dance. He replied: “My philosophy of dance? I make it up. You watch it. End of philosophy.” (And you’ll be glad to know that he got the job, too!)
Getting Started with Arduino, 2e, Ch. 2: The Arduino Way (0 exercises)