Good afternoon, dear viewers, and welcome to the Hobby Home electronics channel.
Today I will show you a modification of a ten-band spectrum analyzer with RGB LEDs.
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.
Based on the circuit diagram, we get a double-sided control circuit board.
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.
A simple RGB controller will be used as an external pulse-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.
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.
Next, let’s proceed to the installation of radio components on the control circuit board.
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.
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.
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.
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.
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.
Install all the buttons with switches, an audio jack and a power input on the control panel.
Install M3 screws and brass racks on the back panel of the case to mount the control circuit board.
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 a back panel.
Connect the printed circuit board with the buttons and switches installed on the control panel.
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.
Next, let’s proceed to the final installation of the spectrum analyzer case.
Fasten all the side and front parts together with M3 screws.
After the work done, we get a finished device with case dimensions of 385 mm in length and width.
The video simultaneously shows four modes of operation of the spectrum analyzer.
The operation of the spectrum analyzer is best observed live and in a darkened room, since it is hard to transmit all the color saturation through the camera lens.
All the necessary information for this device you can find in the description under the video.
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