Published October 24, 2018 © GPL3+

Raspberry Pi Audio Spectrum Display

Use the DFRobot 64x64 RGB matrix panel with a Raspberry Pi 3 B+ to bring a dance party with you wherever you go!

IntermediateFull instructions provided2 hours13,605

Things used in this project

Hardware components

DFRobot 64 x 64 RGB LED Matrix

DFRobot Raspberry Pi 3 B+

Adafruit RGB Matrix HAT

DFRobot ESP32 FireBeetle

Software apps and online services

Raspbian

Python 2.7

FileZIlla

Hand tools and fabrication machines

Soldering iron (generic)

Story

DFRobot reached out to me to do a sponsored project for their 64x64 RGB LED matrix. At first I had tried to use it with the ESP32 Firebeetle, but I couldn't get the library to work. So that meant using a Raspberry Pi 3 B+.

Video

Circuit

Adafruit also has a guide that you can follow here: https://learn.adafruit.com/adafruit-rgb-matrix-plus-real-time-clock-hat-for-raspberry-pi

Thankfully Adafruit has a matrix HAT for the Raspberry Pi that handles all of the 3.3v -> 5v logic level conversions.

Both the HAT and matrix have the same connector, but pin 8 (the white wire) doesn't get plugged into the HAT. Because the HAT only supports up to 4 control wires, pin 8, which is the 5th control wire, gets connected to GPIO pin 24.

Make sure to use a 5V power supply that can supply up to 7A.

Library

For the attached code to work I used the rpi-rgb-led-matrix library to control the LEDs. It's pretty simple to install. Just run

curl https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/rgb-matrix.sh >rgb-matrix.sh
sudo bash rgb-matrix.sh

Then press y to continue and choose option 2 to select the Adafruit Matrix HAT.

Then choose number 2 to free up pin 18 so that sound can still be outputted over the audio jack.

To test it go into the examples-api-use directory and run

sudo ./demo -D0 --led-rows=64 --led-cols=64 --hardware-mapping=adafruit-hat

You should see the demo running. Just hit ctrl-c to exit it.

Running the Code

Before the code can run you must add the root user to the audio group with

sudo -su

then

modgroup audio
exit

Put the python file and test.wav file into /home/pi/rgb-led-matrix/bindings/python/samples/ If the demo ran fine then run the code with

sudo cd /home/pi/rgb-led-matrix/bindings/python/samples/
sudo python spectrum_matrix.py

You should hear the music playing from the audio jack and the lights lighting up.

Code

Pi Code

import alsaaudio as aa
import wave
from struct import unpack
import numpy as np
from rgbmatrix import RGBMatrix, RGBMatrixOptions, graphics

wavfile = wave.open('test.wav')
sample_rate = wavfile.getframerate()
no_channels = wavfile.getnchannels()

options = RGBMatrixOptions()
options.rows = 64
options.cols = 64
options.chain_length = 1
options.parallel = 1
options.hardware_mapping = 'adafruit-hat'
Dmatrix = RGBMatrix(options=options)
Dmatrix.Clear()

chunk = 4096

matrix = [0] * 64

weighting = [0]*64
weighting[0] = 2
power = []

for i in range(63):
	if i%2==0:
		weighting[i+1] = 2**(2+i)
	else:
		weighting[i+1] = 2**(1+i)

output = aa.PCM(aa.PCM_PLAYBACK,aa.PCM_NORMAL)
output.setchannels(2)
output.setrate(sample_rate)
output.setformat(aa.PCM_FORMAT_S16_LE)
output.setperiodsize(chunk)

def piff(val):
	return int(2*chunk*val/sample_rate)
	
def calculate_levels(data, chunk, sample_rate):
	data = unpack("%dh"%(len(data)/2),data)
	data = np.array(data,dtype='h')
	fourier = np.fft.rfft(data)
	fourier = np.delete(fourier,len(fourier)-1)
	power = np.log10(np.abs(fourier))**2
	power = np.reshape(power,(64,chunk/64))
	matrix = np.int_(np.average(power,axis=1))
	return matrix

data = wavfile.readframes(chunk)
while data != '':
	output.write(data)
	matrix = calculate_levels(data,chunk,sample_rate)
	#print(matrix)
	Dmatrix.Clear()
	for y in range(0,64):
		for x in range(matrix[y]):
			x *=2
			if x < 32:
				Dmatrix.SetPixel(y,x,0,200,0)
				Dmatrix.SetPixel(y,x-1,0,200,0)
			elif x < 50:
				Dmatrix.SetPixel(y,x,150,150,0)
				Dmatrix.SetPixel(y,x-1,150,150,0)
			else:
				Dmatrix.SetPixel(y,x,200,0,0)
				Dmatrix.SetPixel(y,x-1,200,0,0)
	data = wavfile.readframes(chunk)

Credits

Evan Rust

122 projects • 1087 followers

IoT, web, and embedded systems enthusiast. Contact me for product reviews or custom project requests.

Raspberry Pi Audio Spectrum Display

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Video

Circuit

Library

Running the Code

Schematics

Board

Code

Pi Code

Raspberry Pi RGB Matrix Library

Credits

Evan Rust

Comments

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Raspberry Pi Audio Spectrum Display

Raspberry Pi Audio Spectrum Display

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Video

Circuit

Library

Running the Code

Schematics

Board

Code

Pi Code

Raspberry Pi RGB Matrix Library

Credits

Evan Rust

Comments

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