Introduction: Music Show Box
Sergio Florido Becerra and Asunción Bueneke Ndje, students of 'Creative Electronics', a Beng Electronics Engineering module at the University of Málaga, School of Telecommunications. We decide to make as final project a derivation of Arduino LED Audio Spectrum.
The Music Show Box gets the audio from a mini-jack input, plays the audio in stereo and represents the instensity of the different audio frequencies in 14 columns of light. 7 for the left audio input and 7 for the right audio input. We put 7 neopixels for column turning out to be 98 neopixels the amount we needed to use.
Supplies
MATERIALS:
- Microcontroller: We decided to insert our own one in the circuit but you can change the next materials for an Arduino Uno.
- 1x ATMEGA328P
- 1x R 1M
- 1x R 10k
- 2x C 22pF
- 1x Crystal 16MHz
Step 1: Make the NeoPixels Work
We started making the Neopixels work with an Analog input so we can adjust our code to the final one with the MSGEQ7. In this case, we used a potentiometer as an audio input to an analog pin of an Arduino Uno so we can control which Neopixels will switch on by changing the pot value.
Step 2: Make ATMEGA328P Programmable
This step is not a necessary one, you can just use an Arduino Uno as a microcontroller of the project, but we decided to do it with the ATMEGA328P. To make this work, we needed to be able to program an ATMEGA328P, so we followed the instructions of the video bellow.
Step 3: Make the Circuit With the MSGEQ7
If we can switch on the neopixels with a pot, we can use the MSGEQ7 with an audio input to control the Neopixels. We just have to put together the circuit and adapt the code so we can work with the MSGEQ7.
The MSGEQ7 is a 7-output multiplexor where each output is equalized to a certain frequency, so, by a digital input pin, we can change the channel of the multiplexor getting the analog value of the frequency we want to represent.
Step 4: Make the Audio Circuit
In addition to switch on the neopixels, we wanted to play the audio that we were feeding into the circuit. To make this possible, we needed to create a parallel circuit at the audio input where we could amplify the signal and play it through the speakers.
We used two 5V mono audio amplifier, one for each input. To make this possible, we followed the instructions of its manufacturer and we used 2 resistances of 100k to get a gain of 5 for each amplifier.
Attachments
Step 5: Make the Box
We decided to use a 3D Printer to make all the cover of the circuit including the power supply and both speakers. We also designed a fastening for the neopixels, so we needed them to be aligned.
The programs used to make the 3D printing are:
Freecad: used for the design of the box we will use. From this design, we will also export the file in STL format.
PrusaSlicer: to laminate our design using the file with extension .stl exported from freecad. In PrusaSlicer, after the completion, we have exported our design in GCODE format and we have sent it into our 3D printer.
PARTS OF 3D DESIGN
Our design will be 14 x 7 neopixels, structured in the following way:
Box base: It will contain the entire circuit composed of 2-dimension speakers (70x 35mm), 2 insertion boards (70x40mm) for an audio and a power supply. The gaps around the box are designed for air circulation.
Connectors face: on this side, we will have a speaker and the two connectors, F-minijack (10x10mm) and the power supply (70x30mm).
Neopixels support face: The dimensions of the holes that will be attached to the strips of the neopixels are 135.12x11 mm and a separation of 8.05 mm.
The box was too big to print in the 3D Printer in one go, so we had to divide it into two, print every part in different times and glue them together.
Step 6: Assemble
To hide the circuit while showing the light of the Neopixels we bought two white plastic folders that were translucid. We cut them out so they adjusted to the width and length of the front that holds the neopixels and we tightened all up with screws.