Summary of Back to the 1980s with the Graphic EQ
This article describes a retro-inspired 2-channel Graphic EQ and spectrum analyzer built using an Arduino Uno R3 and the MSGEQ7 chip. It highlights the author's nostalgic approach to recreating 1980s audio visualizers, utilizing basic electronics knowledge and no special tools. The project displays seven frequency bands plus a rolling average across two 8x8 LED matrices, providing a real-time visual representation of left and right audio channels.
Parts used in the 2-Channel Graphic EQ:
- 3 off prototyping wires male/male connectors (Red, Black, Green)
- 5 off prototyping wires male/female connectors (Red, Black, Blue, Green, Yellow)
- 2 off 8x8 Led Matrices
- 1 off Light Dependant Resistor (LDR)
- 1 off 22K Resistor
- 1 off Arduino Uno
- 1 off Spectrum Shield
- Arduino LedControl library
For those of you who remember the eighties, this will no doubt bring back fond memories when every piece of audio equipment in the known universe was at the time equipped with a plethora of LEDs.
More specifically the ubiquitous Graphic Equaliser or ‘Graphic EQ’.
This Instructable is centred around the MSGEQ7 to create a simple 2 Channel Graphic EQ (actually a simple spectrum analyser) and documents my first, poor attempt at using the Arduino Uno R3, the Arduino development environment and coding in ‘C’ for well over a decade.
To make the above the circuit you require no tools, a basic knowledge of electronics and the following parts/libraries;
- 3 off prototyping wires male/male connectors in the picture above (Red, Black and Green) to connect to the Light Dependant Resistor (LDR).
- 5 off prototyping wires male/female connectors again in the picture above (Red, Black, Blue, Green and Yellow) to connect to the 8×8 Led Matrix.
- 2 off 8×8 Led Matrices. From leading-star on Amazon. £1.90 (This was the price at the time of purchase, but I have noticed they are slightly more expensive, priced at £2.09 at the time of writing this Instructable).
- 1 off LDR. From Farnell.
- 1 off 22K Resistor. From Farnell
- 1 off Arduino Uno. From Proto-Pic £18.65. www.proto-pic.co.uk/arduino-uno/
- 1 off Spectrum Shield. From Proto-Pic. £22.25. www.proto-pic.co.uk/spectrum-shield/
- The Arduino LedControl library in Git Hub. https://github.com/wayoda/LedControl/releases
The circuit allows for the display of left and right audio channels. Seven of the columns of each 8×8 display represent a scaled analogue of the following frequency components present in the audio signal path at any transient in time.
16kHz, 6.26kHz, 2.5kHz, 1kHz, 400Hz, 160Hz and 63Hz
The data sheet for the MSGEQ7 can be found here; https://www.sparkfun.com/datasheets/Components/General/MSGEQ7.pdf
The last column represents a rolling average value of all the frequency components.
For more Details: Back to the 1980s with the Graphic EQ
-
What components are required to build this circuit?
You need prototyping wires, two 8x8 LED matrices, one LDR, one 22K resistor, an Arduino Uno, a Spectrum Shield, and the Arduino LedControl library. -
How many frequency components does the display show for each channel?
Seven columns represent specific frequency components: 16kHz, 6.26kHz, 2.5kHz, 1kHz, 400Hz, 160Hz, and 63Hz. -
What does the last column on the display represent?
The last column represents a rolling average value of all the frequency components present in the signal. -
Can this project be built without any tools?
Yes, the text states that making the circuit requires no tools and only a basic knowledge of electronics. -
Which microcontroller is used in this project?
The project uses an Arduino Uno R3 with the Arduino development environment. -
Does the device support stereo audio input?
Yes, the circuit allows for the display of both left and right audio channels. -
Where can I find the datasheet for the MSGEQ7 chip?
The datasheet is available at the provided Sparkfun link mentioned in the article. -
What library is required to control the LEDs?
The Arduino LedControl library from GitHub is required for the project.
