Introduction: Light Theremin With Magnet Holder

This is a project developed during our ”Taller de inventos” (August Build Night), sponsored by Instructables and Jameco. You can read more about the event over here.

Here we’ll show you how to make a light theremin that has a

Here's a video of the theremin


1x Wazzabi Punk PCB
1x Red LED
2x 555 Timer IC
1x On/off Switch
1x 9v Battery
1x 9v Battery Snap
8x Short cables
6x Long cables
1x DVD case
3x Strong magnets (recycled from garbage, don’t know what they were for)

1x 330 ohm
1x 1 kohm
1x LDR
1x two axis joystick potentiometer (recycled from a broken USB Gamepad)
1x A50K Potentiometer

10 nF
103 ceramic
104 ceramic
473 ceramic

At the bottom you will find the Fritzing file with the schematics and PCB of the circuit we used.

Step 1: Making the PCB

The first step of this instructable is printing the PCB. You'll find attached the necessary PDFs.

Since this task excedes our instructable, feel free to follow these instructables instead:
- How to make the PCB board (available in Spanish)
- PCB making guide

We suggest you mark where every component goes with a sharpie marker on the rear side of the PCB.

Step 2: Prepare the Two-axis Potentiometer From the Controller

Here we'll be cutting from the main PCB of a broken USB Gamepad the part that we need, namely, the part with the 2-axis potentiometer.

Since we'll be soldering our cables to the PCB, we just need to cut around the potentiometer in any way we find appropriate.

Step 3: Soldering the Components

We suggest you mark where every component goes with a sharpie marker on the rear side of the PCB. Once you have the components in place, solder them to the PCB.

We soldered them in the following order:

1. Resistors
2. Capacitors
3. LEDs
4. 555 Timer ICs
5. Cables
6. A50K Potentiometer
7. Switch
8. Speaker
9. 2 Axis potentiometer
10. Battery connector

The crossed cables may be a little confusing but look at the PCB image we took from Fritzing to figure out where each cable goes.

Step 4: Preparing the Case

Now it’s time to cut our DVD case to fit the circuit. We can use pliers or a scissor to cut open the parts that we need.

First we cut a rectangular spot for the battery to fit. Then we glued the magnets to the bottom of the case. We also made a small cut at the center of the case for the cables to come out.

Make a hole for the switch at the bottom left corner of the case, or wherever you feel it suits.

Both the main PCB and the joystick potentiometer are glued to the case as well, and we put the speaker on one of the corners. Make sure the weight is balanced on the case so it won’t tilt when you place it on the fridge.

See the Theremin in action over here