Nov 7, 2011

Short Circuit Workshop 1: Oscillator Circuit


Short Circuit is an afterschool program run by the Institute of Play at Quest to Learn that was piloted in the fall of 2010. It “is an informal hands-on laboratory for participants to explore and discover innovative uses for physical and digital materials, like circuits, conductive inks, LEDs, the latest programming languages, paper, pipe cleaners, iPads, video, audio and websites.” [1]

I interned for the program once a week in the spring of 2011 and remained very interested and invested in the direction of the program. I was asked to substitute for a session when the regular instructor, Don, had to travel on other business. It was the perfect chance to work directly with one of my target audiences and accepted immediately. For this session, Don had designed a lesson from an exercise in Handmade Electronic Music that used an integrated chip and varying values of resistance and capacitance to manipulate square waves and generate sound. [2]


My main research goal for this workshop was to gain hands-on experience working with a middle school population. I consider this a task analysis exercise to develop my own skills as a physical computing instructor and also as a means of reflecting on the difficulties other instructors might encounter.

I focused on my own ability to explain the concepts, to guide the class through the lesson, and to manage behavior. I focused on gauging their level of understanding of electrical concepts, their motivation and reaction, and the effects of an afterschool setting.


13 middle school students ranging between 11 – 13 years old
1 mentor-instructor
1 mentor-backup (a teacher from Q2L)


  • oscillator circuit toolkit: breadboard, Hex-Schmitt Trigger Integrated Circuit Chip, resistors, capacitors, potentiometers, photoresistors hookup wires
  • soldering irons
  • lead-free solder
  • scrap perforated boards
  • 9 volt battery
  • mini-amplifier


  • Practice soldering on perforated circuit boards and/or have students solder two wires to a 1/4 inch audio plug
  • Introduce students to resistors and capacitors and their roles in a circuit.
  • Understand their underlying electrical concepts by integrating them into an oscillator circuit.
  • Apply these concepts by exchanging the same components of different values of the to understand how different values affect the frequency (resistance) and the range the frequency can cover (capacitance).


  • For students to construct the circuit
  • Draw the schematic and document it on Elgg (Q2L’s social network)


We started with a round of introductions then I explained what we would be doing during the session and what I expected of them. I asked what they had done the previous session. The students informed me that they had made sock puppets with blinking LED eyes. I inquired about soldering, electricity, and circuits, asking them to define certain terms or applications to get a cursory measurement of where and how to commence.

I began with an introduction to soldering: how it works, how to use the iron and solder, and safety measures. Next I divided them into groups to practice soldering components with old perforated circuit boards. The students were very intrigued with this process, but we had to stop earlier than expected to continue on with the lesson and did not get to solder the leads to the audio jack. I recommended to Don that they would need another soldering practice session before moving forward.

Image of the circuit we built. Taken from Handmade Electronic Music (see [2])

During the next part of the workshop, I showed them a circuit that was already built and introduced them to the objects we were using to build it: a breadboard, an integrate chip (IC), resistors, capacitors, and wires. Most of the students had never worked with a breadboard or these components before, and it was quite challenging for me to define them and their functions in a manner graspable to that age group. We began with the breadboard: I drew a diagram of the it then explained how electricity ran through it, how to insert components, and why using a breadbroad was important to building circuits vs. soldering all the components into a circuit (i.e. it is much easier to “debug” or figure out which part isn’t working if there is a problem).

I tried to explain how electricity moved through the circuit to create sound and how different values of resistance and capacitance changed the sound. I lost the students here and decided to take a more active approach by explaining as we built the circuit together, instead of reviewing the components individually and then having them construct it. This was a much better approach, but still problematic since I had to go around and help each group individually. We made it through the IC and resistors, then had to stop due to time.

With 20 minutes left, I had the students stop building their circuits and directed their attention back to the front to show them how exchanging different components changed the sound. This was definitely more engaging for them, but only held their attention for a short time. By then it was time to clean up and end the workshop. We did not have time for students to draw a schematic or upload it to Elgg.


Environment + Lesson Structure

The most immediate challenge was the environment. The workshop took place from 3:30 to 5:30 pm in a classroom on a Thursday afternoon. This setting is not exactly conducive to having students sit in their chairs and listen intently to how a circuit is built. The structure of the workshop was much closer to an in-school class than an afterschool session, an the students did not react kindly to it. I was also a factor as a new instructor. The students did not know me and assumed the “substitute teacher” attitude. Since I would only be there once, there was not as much to invest in our dynamic.

There were two mentors at the workshop. I was the only mentor with physical computing experience and the other mentor was a teacher from the school who the students were familiar with. This made it extremely difficult to give individualized help, which became absolutely necessary. Students who weren’t receiving help became distracted since there was nothing to work on while they waited for me to come around. This put more stress on Michael for crowd control, which was less than effective since the lesson was not structured effectively.

Audience (aka becoming middle school friendly)

I was under the impression that they had a developing knowledge of electricity and a cursory understanding of how electricity worked in a circuit. When I asked them what a breadboard was and why it was important in physical computing, ninety percent of the students looked at me as if I was speaking another language.

I realized very quickly that my approach to teaching this workshop would need to be adjusted to fit my audience. While I have taught basic physical computing to university and graduate level students, this was my first time adapting it to a middle school age range. The terminology was problematic and the concepts were too abstract. My most memorable moment occurred when one of the students asked me (so genuinely) if I could stop using “adult language.” I found this extremely difficult to do. My experience teaching basic programming concepts to middle school students who were learning visually-based programming platforms (GameMaker and Aris) was quite different and in my opinion, slightly easier. The analogies available are easier to relate to the students at their level: this makes them quicker to improvise and adapt to a specific learning style and issue. Electricity and physical computing, however, require very specific analogies based on the components you are using. Compiling existing analogies, developing new ones, and documenting them all is one of my new goals.

The soldering exercise was also problematic. The students didn’t take the safety precautions as seriously as they should have. I had to stop numerous times due to ill-use (watching solder drip on the desks), rowdiness (students becoming animated with soldering iron in hand), or general carelessness (putting the soldering iron on the desk). I also tried to immediately teach them best practices of soldering as I was taught (i.e. you never actually touch the solder to the iron, but sandwich the hookup wire in between the solder and the iron). I realized that it was more important to find a way that worked for them. (During the next session, I found that Don had taught them another way to solder that was much more middle-school friendly.)

The “WOW!” factor is not always enough

I went into the workshop with the fallacious assumption that the behavior of the circuit – the piercing, guttural sound of an oscillating square wave – would be enough to excite and motivate students to want to build their own. And I was wrong. For a novice, the barrier to entry of a project (generally) supersedes the “wow” factor. For me, the sustained curiosity of understanding how a circuit can do that – how this intangible thing called electricity can run through these pieces and make a sound – is enough to propel me through it.

Output is an important factor in scaffolding

The type of output can be an extremely effective tool for scaffolding learning. This has been my experience here and my general observation in other research regarding best practices in teaching physical computing to novice younger learners. For example, LEDs are usually the first type of output that a learner encounters. It gives immediate feedback anti is easily understood and constructed in circuit form: there is a power source, an LED, a resistor, and maybe a switch. It is also easy to build on, both in developing creative design applications and teaching other electrical concepts (e.g. parallel vs series circuits).

Sound is generally incorporated later as students become more comfortable with electrical concepts and building and debugging circuits. While it can be much more exciting than a simple LED, it is much harder to conceptualize how electrical energy is transduced into sound waves via an IC and how the frequency and range of the waves is controlled by specific components.

Overall, this circuit and the concept behind it was much too difficult for an introductory lesson. And it was an extremely humbling and enlightening experience for me. It grounded my work in something real and will continue to be formative in how I structure my thesis project.

[1] “Short Circuit,” Institute of Play, accessed November 2, 2011,
[2] Nicolas Collins. Handmade Electronic Music (New York: Routledge, Taylor & Francis Group, 2006), 112-118.

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