Introduction

This Spectrum Analyzer project is nothing other than amazing. It includes a Teensy microcontroller board that drives 2 displays simultaneously at a very high speed.

With it's onboard audio chip, it is capable of doing a frequency analysis of the Audio in realtime to create a Stereo spectrum analyzer of 69 Channels.

Yep you understood me correctly! 69 channels in stereo…so that’s actually 138 frequency bins. On top of that, we will be displaying a stereo VU meter on the second display. So more or less we are really dealing with 140 channels.

But there is more: It can drive up to 3 pixel led matrixes at the same time.. so that adds another 768 LEDS

Best of all: It's open source!

What do you need?

PCB with all components

But it at my tindy store, all you need to add is displays, a fuse and a teensy controller 4.1 : BUY PCB HERE

Of course, you can just download the gerbers from this project and order it directly from PCBWAY!

Two Displays type: ILI9341 this is the 2.8" version. You can also use the 3.2" version

Teensy 4.1 microcontroller Board

External Ram for the Teensy ( you need to solder that on to the teensy board)

Fuse 2AT TR5 if you are using the onboard PSU ( you can use USB on teensy instead )

Some headers or connectors to connect the wires, or solder directly onto to board.

Headers

Sockets

One electret microphone if you'r using mic input

Three push buttons to operate ( Two if you're not using the pixelled matrix )

Three Potmeters, I use 10K versions ( only needed when you add the pixelled matrix)

Special Teensy 4.1

You need to use a Teensy 4.1 with added ram. This means you have to buy a ram chip and add it on to the Teensy Board.

Without this external Ram , it will not work.

Connecting a few wires

Since most components are directly connected to the pcb, the number of needed wires are kept to a minimum

You can look at the schematic for details, however in short, it comes down to this:

Potmeters ( brightness, peak delay, input gain) only if you are using a led matrix wil go to connectors CN5,CN6 and CN9. Connect the center of each potmeter to the center pin of the connector. connect the other 2 pins of the potmeter to the remaining pins of each connector. If your potmeter is reacting CCW instead of CW, or vise versa, simply swop the outer two pins of that potmeter.

Switches:

switch 1: CN2

Switch 2: CN4

Switch 3: CN9 pins labeled (- and s )

Microphone goes to connector CN11

Line in goes to connector CN3; the two outher pins are ground and the two inner pins are channel L and R

Power in goed to U1, pay attention to the markings on the board: + and - use 8-12VDC

Ledmatrix ( I used 3 matrixes in series. each matrix has 16 x 16 leds ) Connector CN10, look at the markings on the pcb to see the +,- and L ( L = data line )

Just a few more components to finish this amazing build

There are only a few components you need to add.

There is the Teensy Module with the added extra RAM

Two Displays. Take note that the displays are mounted on the bottom side of the PCB

A fuse of 2A if you are planning to use the onboard powersupply. If you are using the Teensy USB connector, you don't have to add that fuse.

You have to add some headers and sockets to install the displays and the Teensy. I wouldn'r recommend to leave those out. At some point, you might want to change some of those components and soldering those directly to the board will make that hard.

Adding the matrix

I used a matrix of pixelleds that you can buy pre-assembled.

The one i used is this: 16 x 16 matrix I put three of those in series.

You could use other matrixes as well, even ledstrips could work but you wil have to adjust the firmware of this project.

Also, if you are using different kind of matrix, leds or ledstrip, you might have to change those settings in the firmware as well:

Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(kMatrixWidth, kMatrixHeight, LED_PIN,

 NEO_MATRIX_BOTTOM    + NEO_MATRIX_RIGHT +

 NEO_MATRIX_COLUMNS + NEO_MATRIX_ZIGZAG,

 NEO_GRB           + NEO_KHZ800);

Adding the Teensy Board plugin to Arduino

I used Arduino IDE with Teesyduino:

Arduino IDE 1.8.15

Teensyduino, Version 1.54

You can download ARduino here: https://www.arduino.cc/en/software

Click here for a tutorial about installing Arduino

Make sure you use the Arduino IDE and not the windows app ( incompatible with the Teensyduino )

You can download Teensyduino here: Download TeensyDuino

Click here for a tutorial about installing TeensyDuino

Adding the libraries

I did a succesful compilation using the following library versions:

Using library Wire at version 1.0

Using library Audio at version 1.3

Using library SPI at version 1.0

Using library SD at version 2.0.0

Using library SdFat at version 2.1.0

Using library SerialFlash at version 0.5

Using library ILI9341_T4-main at version 0.1

Using library tgx-main at version 0.5

Using library EEPROM at version 2.0

Using library OneButton at version 2.0.4

Using library IRremote at version 3.6.1

Using library TeensyID-main at version 1.3.3

Using library ILI9488_t3 at version 1.0

Using library Adafruit_NeoMatrix at version 1.2.0

Using library Adafruit_NeoPixel at version 1.7.0

Some of the mentioned library are part of the Arduino and/or Teensy framework but others need installing:

TGX - a tiny/teensy graphics library: <https://github.com/vindar/tgx>

Arduino OneButton Library: <https://github.com/mathertel/OneButton> (install via the Arduino library manager)

IRremote Arduino Library: <https://github.com/Arduino-IRremote/Arduino-IRremote>

TeensyID: https://github.com/sstaub/TeensyID

Optimized ILI9341 screen driver library for Teensy 4/4.1, <https://github.com/vindar/ILI9341_T4>

Programming

You need to download the sketch from this project, you can find the link below.

Best way to proceed is to copy all the files to a new folder.

It is important that all files stay together so if your Arduino want to rename the folder after opening, fine,,but make sure you copy all the other files to that folder. If you don't, compiling will give you error's like "not found"..

Compile and upload the sketch.

In case the upload to the Teensy will not start, you can press the button on the Teensy to help you.

Show and Tell

Well, I have many photo's to show but I will start with a video that says it all: