Introduction: RGB 10 Band Led Spectrum Analyzer

About: Hey everyone! My hobby is electronics. I share my experience in the development of devices made in the home with my own hands.

Good afternoon, dear viewers and readers. Today I will show you a modification of a ten-band spectrum analyzer with RGB LEDs.

Step 1: Links to Radio Components.

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You can find all the necessary information for repeating this device by clicking on the link to Patreon:

Links to radio components:

Radio parts store:


Mini RGB controller:

RGB wire:

Microchip Atmega 8:

Microchip TL071:

Microchip CD4028:

Stereo jack socket:

DC power connector:

Multi-colored buttons:

Buttons On/Off:

Dupont connectors 2.54 mm:

Header & Socket connectors 2.54 mm:

Mounting racks:

Mounting plastic racks:

Step 2: Circuit Design.

In order to make it possible to connect a more powerful load, such as an RGB LED strip, or to connect several RGB LEDs, some changes to the transistor switches in the circuit diagram of the spectrum analyzer were made.

On the diagram you can see that the emitter of each BC557 transistor is connected to the positive output of an external RGB pulse-width modulator, and the collector is connected to the positive contact of the RGB LED. Each individual collector of the BC337 transistor switch assembly is connected to each individual negative contact of the RGB LED, and the emitter is connected to each individual negative output of the external RGB modulator.

Step 3: PCB Layout.

Instead of the usual RGB LED strip, in this project I will use five-millimeter RGB LEDs to create the matrix. For this purpose a small printed circuit board was designed.

Step 4: RGB Controller.

A simple RGB controller will be used as an externalpulse-width modulator. On the device itself there are three buttons with which you can change the color, speed and light intensity, and there is also a memory function of the last mode after power off.

Step 5: 3D Visualization.

To create 3D visualization and drawings of the spectrum analyzer case I used KOMPAS 3D. All the drawing files were converted to DXF format and transferred to a plastic sheet company.

Step 6: Installation of Radio Components on the Control PCB.

Next, let’s proceed to the installation of radio components on the control circuit board.

Step 7: Microcontroller Programming.

After mounting and soldering all the radio components, let’s proceed to the microcontroller programming.

Connect the programmer and the microcontroller by ISP cable and connect the programmer to the USB port on the computer.

This time, Amega 8 microcontroller programming will be carried out in AVRDUDE.

In the opened window, select Amega 8 from the list of microcontrollers in the Chip tab. In the Programmer Settings tab, select STK500 and virtual COM port three, then go to the Fuses tab and check all the boxes as shown in the video. Record the set fuses in the microcontroller memory.

Next, open the Programming tab and select the HEX file stored on the computer and also record it in the microcontroller memory.

Step 8: Installation of the Radio Components on the Small PCB for the LED Matrix.

Now let’s proceed to the installation of the radio components on the small printed circuit boards for the LED matrix.

After a long soldering and mounting process, you should get one hundred printed circuit boards with RGB LEDs and current-limiting resistors.

To connect the LEDs to each other use a four-conductor colored wire.

Before soldering, remove all excess insulation and tin the wires.

Step 9: LEDs Frame Assembly.

Next, let’s proceed to the installation of twenty-millimeter plastic racks on the internal vertical and horizontal front ribs for additional rigidity of the spectrum analyzer case. After assembling the ribs you will get a frame with one hundred individual cells for LEDs.

Step 10: LEDs Installation.

Now let’s install the LEDs on the middle panel of the case. Insert each LED into a five-millimeter hole on the panel.

To hold the LEDs better, we will use super glue.

At each individual horizontal level of the matrix, connect all the positive contacts of the LEDs to each other by a white wire in one line, and solder the RGB wire to the first LED of each column for further connection to the control circuit board.

Step 11: Wires Preparation for Connection.

Next, prepare the wires for further connection of external buttons and switches.

To avoid short circuit isolate each individual wire with a heat shrinkable tube.

Repeat the same process with an audio jack and a power input.

Solder the wires on the printed circuit board of RGB controller instead of membrane buttons to connect to external mode switches.

Step 12: Control Panel Assembly.

Install all the buttons with switches, an audio jack and a power input on the control panel.

Step 13: PCB Installation on the Rear Panel.

Install M3 screws and brass racks on the back panel of the case to mount the control circuit board.

Step 14: Case Assembly.

Insert M4 screws into the holes on each side of the back panel, then mount 12 parts, fixing them with nuts.

Fasten all the side parts with corners and aback panel.

Connect the printed circuit board with the buttons and switches installed on the control panel.

Fasten all the side and front parts together with M3 screws.

Before finally completing the assembly of the spectrum analyzer case, you need to glue the perforated black film on the front panel made of frosted organic glass.

For better positioning of the film on glass, we will use a solution of soapy water.

Step 15: Work Result.

After the work done, we get a finished device with case dimensions of 385 mm in length and width.

Step 16: End of Instruction

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