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The Optical Theremin is an adaptation of the original Theremin electonics instrument, which is notoriously played without touching anything. The original instrument was made in 1920 and uses the interference of hands in Electromagnetic Fields to produce music. The Optical Theremin uses two cameras instead, which track hand movements and convert those to music!

The Optical Theremin was created by two Electric Mayhem Alumni '26 as their senior project.

Software / Hardware

Software

Cardinal: Plays the sound

Theremin Program: Hand tracking software, converts to MIDI inputs

QJackCtl: Acts as a bridge between the Theremin Program and Cardinal

Hardware

Arducams of some description

Dell PC - running Debian Linux

Section 2 | Mechanical Setup

Storage

The Theremin fits in one tall EXPO box. The box contains:

Theremin Base
Theremin Screen
Tower Camera
Spare Ethernet Cable + USB Adapter
Spare Keyboard
Audio Cables

Assembly

> Take the Theremin Base out of the box, and set it on a table near power.

> Place the Tower Camera in the little green base, with the front of the tower camera facing away from the camera embedded in the base.

> The Theremin Screen has velcro on the bottom to be attached to the Theremin Base.

All cables should remain where they are, plugged into the Theremin Screen or Tower Camera.

Section 3 | Program Setup

Turning it on

note: The password and username for the Theremin's computer are on a sticker on the computer, they should only be needed for debugging

There is a power button for the computer on the left side of the Theremin Base, as well as a power button on the left side of the Theremin Screen. When the Theremin boots up, the desktop menu should look like the image on the right.

note: If it doesn't, turn to the troubleshooting section

Cardinal Setup

> Open the blue File directory in the taskbar

> Open the Home directory in Files

> Open the "Cardinal" folder, and open the program CardinalJACK for later

Theremin Program

> Use the dash and two dots at the top left corner of the screen/the windows key to return to the desktop view.

> Open Files > Home > Theremin

> In the Theremin folder, hover over any empty space and hold to open a small menu (Image on right)

> Select "Open in terminal"

This should open a terminal with the directory of the username + Theremin (folder).

> Either type "source .venc/bin/activate" into the command line, or use the up arrow key to find it in recent usages, and click enter

> Then type "python ui.py" into the command line, or use the up arrow key to find it in recent usages, and click enter

This will open the Theremin Program.

> Click the Refresh button at the bottom and the drop down menus should fill in

> Keep the camera on the right as is, use the left dropdown menu to switch the Tower camera* to the second option in the drop down, and click apply

note: If you apply these incorrectly, you will need to restart the software.

> Click "Start Tracking" at the top, and the camera feeds should appear

QJackCtl/Patch Board

> Use the dash and two dots at the top left corner of the screen/the windows key to return to the desktop view.

> Click the 9 dot grid in the taskbar, and open the "QJackCtl" program

> Click the "Graph" button in QJackCtl, and a Patch Board should appear (Image on right)

> From the “Midi-Bridge” input on the left, drag the bottom most red option and drag it to “events-in” in the center block

> Drag “audio_out_1” to “playback_FL” in the “AC511 Sound Bar Digital Stereo” block

> Drag “audio_out_2” to “plackback_FR” in the same place

CardinalJACK Usage

> At the top menu, go to File > Open > Home > Theremin > Patches, and select any of the Patches (different effects) in the folder (We usually use the Spacey one)

This will change the layout of the board.

> Find a red glowing button, possibly labelled mute (depending on the patch used) and click it to unmute.

> There should be a Dim button or slider if it is too loud

> Scroll all the way to the left and find the "Cardinal Host MIDI CC" block

> Make sure that the inside of the input wires turns green when a hand is detected by the Theremin Program

Section 4 | Take Down

Make sure to CLICK THE STOP TRACKING BUTTON BEFORE CLOSING THE THEREMIN SOFTWARE. Otherwise, all the other softwares can be closed as usual.

Remove the camera tower from the green triangle
Remove the Theremin Screen from the velcro

Section 5 | Troubleshooting

Section 6 | Talking Points

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