Spectrum Analyzer POV Display

This Instructable is about how I made a Spectrum POV display using an Arduino ATmega 328 and incorporated it into my Tachyscope Laser project.

I have omited many smaller basic steps in this build, like builfing the turn table drive, balancing the turntble( platter).

Also I will not be talking about the control panels in this post, they have been covered in my earlier ones.

The Spectrum Analyzer

Using 8 White leds and 1 blue led as a status indicator, mounted to the rotating 12" platter controlled via ATmega 328 IC1 also on the spinning platter. The Arduino receives 2 signals. 1 for serial data / control functions and the other the audio analog input. Power and data signals are delivered via a 8 pole slip ring below the platter.

A home switch synchronizes the display timing.

The electrical schematic is pretty straight forward, an Arduino controlling a few leds, a home switch input, Rx data input and analog audio input.

The platter rotates CCW ( counter clock wise). The faster the spin the smaller ( tightly packed ) will be the display images.

Attached are schematics and Arduino code listing for the POV circuit.

I can make more info available for those interested in this project, just let me know, Im more than happy to share.

The Arduino code was generated with the help of Open AI, as I'm not a programmer just a hobbyist , It works as needed for me. feel free to download and try, I take no responsabilty for the performance of this code, use as an example for testing.

Supplies are dependant on what you will want to build..

I think there is enough details in the images and documentation to extrapolate what is needed, way to many items to start listing. Basically an Arduino ATmega 328, small leds for display, resistors, 16Mhz xtal and capacitors, slip ring or batteries to power the rig, if using batteries.. consider a wireless audio link device to get audio into the Arduino.

and external home switch connected to ground and input i/o2, (pin # 4). and pulled up via 10k resistor.

reset = U1 pin 1

Rx data = U1 pin 2 = i/o 0

Tx data = not used = i/o 1

Home sw = i/o 2

display leds top of display

LED D1 goes to i/o10

LED D2 = i/o 3

LED D3 = i/o 4

LED D4 = i/o 5

LED D5 = i/o 6

LED D6 = i/o 7

LED D7 = i/o 8

LED D8 = i/o 9

LED D9 = i/o 12 blue led

Audio input = A1 (pin 24)

Pin #2 on the Arduino is the RX in, configured for 9600 baud. Serial data received will be displayed on the scrolling message POV in white letters. a blue marker line will indicate the circumference of the display. ( RX will display after boot up is completed).

At boot up, the message " Booting UP ------- Tachyscope Laser POV, NVictria technology V2.0, 9600 baud " will scroll across the POV screen from right to left 1 time.

then display, " waiting for serial " , at this point RX data will be displayed.

serial commands to tell the Arduino to either display serial characters ( letters and numbers) or the Spectrum analyzer .

in the serial data stream, " a space character followed by Sw1" will put the POV display in LARGE spectrum mode. any audio on pin # 24 of the Arduino will be displayed on the Spectrum display in large font.

"sp" Sw1 = large spectrum

"sp" Sw2 = small spectum

"sp" Sw3 = serial mode on display in text

"sp" Sw4 = RPM mode on display in text

"sp" Sw5 = Vu meter mode displayed on text

and so forth.

all the way to Sw9.

This code is specific to my needs, you will have to make changes for yours.

To recap the code looks at RX for any command that tells it to go to the Spectrum functions ( Sw1 or Sw2 with a prefix of a space char) otherwise display the text data coming in.

The end result of all this is a very cool POV audio and serial text display. The 12" diameter platter creates a 360 "hologram"-ish look.

I used some very OLD technology for this project, like UV-201 vacuum tubes ( 100+ year sold). The laser is a HE-NE tube from Siemens, about (40 years old), and a Dekatron tube, (50 ish years old).

you can use for the audio drive circuit ICs for the amplification easily available, and for the laser , the led from a pointer mounted to the platter rather than a whole bunch of mirrors to guide the beam up the center of the drive shaft tube.

Visit my other projects on Youtube and Hackaday and here at Instructables , under NVIctria, Tachyscope POV, Tachyscope Laser, Danno1802, Victorian Teletype, Spinning CRT .