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lesson

littleBits RGB Oscillator-Scope • Visualizing Sound

by Professor7

Published on August 23, 2017

With just an RGB LED bit and most any smart phone, tablet, web or video camera you can VISUALIZE THE SOUNDS that you make with the littleBits SYNTH KIT! There is a phenomenon that occurs when a video device is placed in front of a RGB LED that is pulsing to sound waves. It allows us to examine sound waves much like an oscilloscope.

The electronic reproduction of sound uses different frequencies to vibrate a speaker or headphones which creates waves in the air that your ear perceives as sound. The littleBits synth kit synthesizes sound by creating different frequencies using an oscillator. Simply put, the oscillator is just turning on and off in a repetitive pattern, and creating a sound wave.

It seems complicated, so that's why I was excited when I discovered this SIMPLE method of visualizing the concept with the littleBits RGB LED!

As a teacher I think some of the most effective lessons are those that include a FUN factor and engage the imagination. What could be more FUN than learning from an LED light show???

Lesson Objectives:

Students will understand a basic theory of electronic audio synthesis.

Students will learn that sound waves can be represented visually.

Students will experiment with sound and littleBits, observe the phenomena and reflect on the results.

 STUDENTS WILL HAVE FUN AND BECOME INTERESTED IN STEAM LEARNING

Encourages students to use multidisciplinary techniques to examine their world and express themselves.

 

Assessment Strategies:

Through observation and discussion, the students understanding of the concepts are made evident.

Example: A students suggestions or answers to questions about how to change the image of the waveform by making or controlling sound with littleBits can allow the instructor to assess their level of experience with / understanding of little bits and the concepts introduced.

 

Although I use this lesson as a demonstration and participation exercise, students can document their work by saving images and video recordings of their experiments, which could be used for summative assessment. 

 

Learning Standards

NGSS

Energy can also be transferred from place to place by electric currents, which can then be used locally to produce motion, sound, heat, or light. 

Standard 9. Understands the sources and properties of energy

Level III [Grade 6-8], Benchmark 8

Knows that waves (e.g., sound, seismic, water, light) have energy, interact with matter, can transfer energy

 

NYS Art Standards

Music Standards 1-a, 2,-a,b,c, 3 -b,c

 

NYS SCienceCC 4.4

 

Observe and describe the properties of sound, light, magnetism, and electricity.

Duration: 15 minute demo - then experiment until the end of the class period.

Credits: I want to thank Peter Edwards and his website casperelectronics.com for being such a cool resource for circuit bending and teaching me about this video phenomenon.

Lesson Guide

STEP 1 : Set up the demonstration (5 -10 minutes beforehand)

-Create a synth circuit (p3, i31, i32, o24) with an ( w1, o3) RGB LED at the end.

-The LED will flash. Make sure that it is adjusted so all R G and B are flashing when sound is coming out.

-Place the LED as close as possible to the camera lens. A phone or tablet can be set directly down on the RGB LED, with just something the size of a pink eraser to balance the device. If you are using a laptop or webcam you will probably need to stick the LED to it somehow. I recommend blue painters tape. Experiment with whatever zoom and exposure controls you have. Every video capture device will give different results. Ones that work the best have control for zoom and exposure lock or adjustment.

see setup video

STEP 2 : Lecture (5 min)

I start by reviewing the relationship of the vibration of objects and sound. Then continue with a description of how a microphone translates real sounds into electronic frequencies, which can be recorded, transmitted, amplified and reproduced by a speaker.

Next I explain that in electronic instruments, sounds are usually created electronically, not real sounds played back. When we use the littleBits Synth Kit, we use an oscillator to generate the sound. The oscillator is used with other electronic components to shape these frequencies to create different sounds.

We are going to use the way that those frequencies make a littleBits RGB LED flash, and a phenomenon that occurs when a video device is placed in front of it, to visualize and learn about sound waves!

STEP 3 : Demonstration (10 min, then experiment with remaining time)

Make some sounds with the oscillator at its lowest setting. It sounds like clicks. Let the class see that it also makes the LED blink. Turn it off.

Show the students a hair comb. Make a sound with a card on the teeth of the comb very very slowly at first. Sounds like clicks too! Make a few more sounds moving the card along the comb faster each time. They sound like notes increasing in pitch. Tell them the faster an object vibrates, the higher pitched sound it makes. That's how the oscillator makes sound. By, turning on and off the electricity repetitively it makes a speaker vibrate, which is picked up by our ears as sound. Explain how measurements of sound frequency literally means how frequent or how many clicks or vibrations per second!

Start making sounds with the oscillator again and fine tune the camera position and settings to get the best image. Make a few sounds with the oscillator increasing in pitch at first as you did on the comb. Lead the students in making observations to compare the sound/sight of the video image to the card on the comb. Does the the video image look like the teeth of a comb? Can we identify and/or chart what video features correspond with which sounds qualities?

Make some more sounds with just the oscillator, and observe the video changes. Compare the square and saw waveform settings. What does the difference look like? Tune the oscillator to a stable frequency and introduce the filter to modify the sound. Are the changes to the video the same as when you changed the oscillator? How do they differ? Add more parts of the synth kit. Add the keyboard to play some of the sounds you make. Do the patterns line up with the octaves? Add the microphone bit and speak, sing, play percussion and musical instruments music through it. Examine the changes in the video patterns it makes. Based on our observations, what predictions can we make?

Students take over! Everyone takes turns to get hands on experience experimenting with, or suggesting ways to explore this new tool.

see demo videos: square vs saw, filter with ring modulation and other examples.

STEP 4 : Discussion (5-10 min)

Leave time for discussion, reflection, and sharing!

What did we learn? What other inventions could be created with littleBits now that we have this technique in our arsenal? Can this technique be applied for a useful purpose? (i.e. tuning two oscillators to the same pitch?) What are the entertainment/performance possibilities with this phenomenon? How fun is this???

I love when learning is fun. I can't wait to see what you all do with it!

Please come back and share!