Daily Archives: 13 May 2013

Arduino Final Project: Distance LEDs

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.

As with all of the exercises that I completed for the book Getting Started with Arduino, the code for this sketch can be downloaded from http://db.tt/f6x9Q4NA (you’ll want the “Distance_LEDs” folder, in this case).

And with that, I think I have finally finished all of the work to get the Art Technology Certificate from the University of Utah Department of Art and Art History that was the purpose for my 2011-2012 sabbatical. Woo hoo!

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GSWA 6: Talking to the Cloud

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:

  • Copy and paste code into Arduino and Processing IDEs (because this one uses both).
  • 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!

Completed:

  • Getting Started with Arduino, 2e, Ch. 6: Talking to the Cloud (1 exercise – but a really, really big one)
  • Sketches (i.e., code) can be downloaded from http://db.tt/f6x9Q4NA
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