Vu Meter Speaker




Introduction: Vu Meter Speaker


In this Instructable I show how to make a simple Vu Meter Speaker.

I thought about this when I found old parts of a radio. Thought it would be fun.

Step 1: Materials

-Arduino uno

-12 LEDs (6 green, 4 yellow, 2 red)

-6 resistors (220 ohms)


-Heat shrink tubes

-Pin headers



-Used/Broken headphones

-Used Speakers (Mine is from an old (dismantled) radio)

-Wood glue

-Press drill

-Electric saw

-Soldering Iron

Step 2: Speakers and EarPhones

First, I retrieved my speaker from an old dismantled radio I had and found a pair of broken earphones.

To connect the speakers to the earphones, I cut off the actual earbuds, and carefully removed part of the sleeve of the two "branches" of the earphones to reveal about 1 cm of the two inner wires.

I then used two wires and soldering materials to connect one of the "branches" to the speakers. I soldered the inner wires with the wires. On the speakers there are two spots where to connect the wires, the direction doesn't matter. After it was connected, I made sure the speaker worked with my mp3 player.

For the other "branch", I connected two wires, one red on the positive inner wire and one black on the ground inner wire. This will be connected to the Arduino later

I then protected my soldering by placing a heat shrinking tube on each connection and a bigger one both pair of wires joined together.

Step 3: WoodWork

I decided to build the casing for my speaker I used scrap pieces of plywood.

For the face of the casing, I used my speaker to draw its outline on the wood and drilled out the hole with the correct size hole-saw. Although, I used a hole-saw slightly smaller than the actual speaker so I would be able to glue it easier later. I then cut my piece to make it in a square.

For the LEDs, I found the right size of the drill bit by testing them on a random piece of wood and placing an LED in them. Once i found the drill bit that provided the good hole size for my LEDs, I drilled 12 holes on the sides. (6 on each, aligned together of course).

For the sides of my casing, I cut two thinner pieces into triangles with the right height so they would fit with the face of the casing. (The length didn't really matter)

Step 4: LEDs

Now, before painting and gluing the wood together, I made the circuitry for the LEDs.

I used the face of my casing to place my LEDs while connecting them together.

I used 12 wires, preferably choosing one color of wire for each color of LED. (As you can see, they unfortunately don't fully match the color of the LEDs, but still :p). In my case, the red LEDs had blue wires, yellow had yellow, and green had white.

First, I soldered the cathode of each side of 6 LEDs together. Then, with a wire I joined the two side's anode together. For the anodes, I connected each with a wire, making sure the wire is the same color for the same colored LEDs. Then, I connected each pair (6 total) of LEDs with a 220 ohm resistor. Finally, I connected each resistor to a 6 pin header. I connected the pairs in order to the pins. (Not so pretty but it works eh)

I used heat shrinking tubes to cover the resistors and prevent faulty connections between them)

NOTE: a pair of LEDs are two LEDs (one on each side) at the same height position!

Step 5: Paint

To paint, I removed the LEDs from the casing, and used dark brown spray paint.

I applied one primer layer and 3 paint layers on each piece of wood, and waited patiently as it dried. (but not really... I did step 7 while it dried)

Step 6: Gluing the Speaker

I used wood glue to glue my speaker.

The two triangular sides were glued on the back side of the front, by the edge. As for the speaker, I applied glue on its side, and placed it in the hole.

And I waited till it dried.

Step 7: Arduino

The code for the Vu meter, is pretty simple.

As the headphones send change in voltages, it can be read by an analog read pin of the arduino. So, I used an analog pin as input to read the data from the headphones. For the LEDs, I used 6 digital pins as outputs.

In my code I set 6 values, for each level. And depending on the value read by the analog read compared to the 6 values, the corresponding LEDs light up.

On the board, I connected the red wire of the other branch of the earphones to the analog read pin A0. The black wire of the branch was connected to the ground. I connected the 6 pin header in the pins 13 to 8. (13 being the red LEDs). I also used the breadboard although it's could be done without.

*The 6 level values are changeable obviously, and a calibration setting could be added later on. (Ex: reading an x amount of analog values, finding the average, and use the average as multiple for the 6 values)

*There is a 5v input limit on the arduino pins.

Step 8: Final Touch

Finally to hide and protect the wires, I glued a piece of felt on the back.

Connected everything with the arduino and an mp3 player, and all done!

Thanks for reading!

*The quality of the sound is not great, but the purpose was to play around with the Vu meter concept

Invention Challenge 2017

Participated in the
Invention Challenge 2017

Explore Science Contest 2017

Participated in the
Explore Science Contest 2017

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