Light Theremin

Light can be a difficult concept for students who have never had vision to understand. This device allows the student to “hear” the amount of light that reaches a photo sensor by utilizing pitch.

I was first introduced to this device last week when my colleague, Jim Clark, had me come and take a look at it as a student operated it. The device he had was built by his music teacher, Mark Rogers.

As we changed the light setting in the room, the pitch changed. As you raise and lower your hand over the photosensor, the pitch changes accordingly.

You may want to find someone with a bit of electronics background to help in building this device. I could not find it available for sale. From my research it is not complicated to build and requires a minimum of materials, which are all available at Radio Shack.

APH (American Printing House for the Blind) offers SALS (submersible audio light sensor) which works in a similar manner.

Materials

breadboard
capacitors
speaker
resistors (large pack)
photoresistor (or photodiodes)

Preparation

This simple description of construction of a light theremin can be helpful http://makezine.com/projects/light-theremin/.

This video of Light Theremin also provides good background.

Procedure

This device can be used for many activities related to light.

It utilizes pitch to describe the intensity of light and will be valuable in raising both the interest level and comprehension of students with visual impairment.

I’m confident that this tool will be invaluable in teaching students with visual impairment. In my limited use of this tool and the APH prototype of SALS, I have already had students differentiate between a light and a dark colored shirt and “hear” a striped pattern. I look forward to utilizing this technology in the classroom.

NGSS Standards

Grade 1 – Waves: Light and Sounds

PS4.B: Electromagnetic Radiation

Objects can be seen if light is available to illuminate them or if they give off their own light. (1-PS4-2)
Some materials allow light to pass through them, others allow only some light through and others block all the light and create a dark shadow on any surface beyond them, where the light cannot reach. Mirrors can be used to redirect a light beam. (Boundary: The idea that light travels from place to place is developed through experiences with light sources, mirrors, and shadows PS4-3

Grade 4 – Wave, Waves and Information
PS4.A: Wave Properties
Waves, which are regular patterns of motion, can be made in water by disturbing the surface. When waves move across the surface of deep water, the water goes up and down in place; there is no net motion in the direction of the wave except when the water meets a beach. (Note: This grade band endpoint was moved from K–2). (4-PS4-1) Waves of the same type can differ in amplitude (height of the wave) and wavelength (spacing between wave peaks). (4-PS4-1)

Middle School: Waves and Electromagnetic Radiation
PS4.A: Wave Properties

A simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude. (MS-PS4-1)

A sound wave needs a medium through which it is transmitted. (MS-PS4-2)

PS4.B: Electromagnetic Radiation

When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light. (MS-PS4-2)

The path that light travels can be traced as straight lines, except at surfaces between different transparent materials (e.g., air and water, air and glass) where the light path bends. (MS-PS4-2)

A wave model of light is useful for explaining brightness, color, and the frequency-dependent bending of light at a surface between media. However, because light can travel through space, it cannot be a matter wave, like sound or water waves. (MS-PS4-2)

High School : Waves and Electromagnetic Radiation
PS4.A: Wave Properties

The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which depends on the type of wave and the medium through which it is passing. (HS-PS4-1)

Information can be digitized (e.g., a picture stored as the values of an array of pixels); in this form, it can be stored reliably in computer memory and sent over long distances as a series of wave pulses. (HS-PS4-2),(HSPS4- 5) [From the 3–5 grade band endpoints]

Waves can add or cancel one another as they cross, depending on their relative phase (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. (Boundary: The discussion at this grade level is qualitative only; it can be based on the fact that two different sounds can pass a location in different directions without getting mixed up.) (HS-PS4-3)

PS4.B: Electromagnetic Radiation

Electromagnetic radiation (e.g., radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons. The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains other features. (HS-PS4-3)

When light or longer wavelength electromagnetic radiation is absorbed in matter, it is generally converted into thermal energy (heat). Shorter wavelength electromagnetic radiation (ultraviolet, X-rays, gamma rays) can ionize atoms and cause damage to living cells. (HS-PS4-4)
Photoelectric materials emit electrons when they absorb light of a high-enough frequency. (HS-PS4-5)

By Laura Hospitál