Introduction: 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 want to show you the complete assembly guide for the 10 band LED spectrum analyzer.

Step 1: Brief Overview of the Technical Features of the Spectrum Analyzer.

1.The reading value is in the frequency range from thirty-one hertz to sixteen kilohertz.

2.Dimensions of the LED matrix: ten rows per ten columns.

3.Possible operating modes: dot, dot with peak hold, line, line with peak hold.

4.The spectrum analyzer is powered by a twelve volt DC power supply.

5.Power consumption depends on the LEDs used in the matrix.

6.Type of input signal: Linear mono.

Step 2: 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:

Spectrum Analyzer Kit on Tindie:

Radio parts store:

Microchip Atmega 8:

Microchip TL071:

Microchip CD4028:

Stereo jack socket:

DC power connector:

DIP switches:

10 segment LED module:

Step 3: Circuit Design.

This 10-band LED sound spectrum analyzer consists of two parts – a control printed circuit board and a LED matrix printed circuit board.

The scheme of the LED spectrum analyzer contains such units as an operational amplifier, a control microcontroller, a binary to decimal decoder, and PNP and NPN transistor switches.

The LED matrix consists of ten modules. Each module contains ten LEDs of different colors.

Step 4: PCB Layout.

1.In order to start assembling the LED spectrum analyzer, you need to find out more about the control circuit diagram and the circuit diagram of the LED matrix by registering on the EasyEDA website or by downloading the archive following the link in step 2.

2.On the EasyEDA website we create Gerber files from the converted printed circuit boards of spectrum analyzer for further production at the factory.

3.Before going to the official website of the printed circuit board manufacturer, the EasyEDA development environment shows us brief information about the characteristics of the printed circuit boards and an approximate cost for 10 pieces.

4.On the website of the printed circuit board manufacturer JLCPCB files can be downloaded automatically through the EasyEDA Gerber development environment. You can also use specific Gerber files from the archive and upload them manually.

5.Afterwards place an order at the designated address and select the preferred delivery time.

The printed circuit boards are delivered in a box with the name of the manufacturer. Inside the box the printed circuit boards are neatly folded in a vacuum packing.

Step 5: Installation of Radio Components on the Control PCB.

Let’s proceed to the installation of radio components on the control circuit board.

Step 6: Installation of Radio Components on the PCB of the LED Matrix.

Next, let’s install the printed circuit board of the LED matrix.

Step 7: Software and USB AVR Programmer.

Let’s proceed to the software part of the spectrum analyzer.

To upgrade the firmware of the Atmega 8 microcontroller we will use the Atmel studio 7.

You can download the free full version of Atmel studio 7 from the official Microchip Technology website.

In order to connect the microcontroller to the computer we will use the Pololu USB AVR Programmer.

Pololu USB is a compact and inexpensive in-circuit programmer for AVR-based controllers. The programmer emulates STK500 through a virtual serial port, which makes it compatible with standard software such as Atmel studio and AVR DUDE.

The programmer is connected to the target device using the supplied 6-pin ISP cable. The programmer is connected to the USB port via USB Type A to Mini B cable, which is also included in the kit.

For the full operation of the programmer download the driver from the Pololu official website.

On the Pololu website go to the Resources tab and select the necessary files with installation drivers and software for the Windows operating system.

Step 8: Microcontroller Programming.

1.Next, connect the ISP cable of the programmer and the 5-pin connector with wires connected to the microcontroller on the printed circuit board, and then connect the programmer to the USB port on your computer.

2.Before programming go to the Start menu, select the control panel, and then select the device manager in the window that appears.

3.In the device manager select the Ports tab. Here you need to look at which virtual port the programmer is connected to. In my case, this is virtual COM port 3.

4.Next, go back to the Start menu and select the programmer configuration utility.

5.In the window that appears you need to change the clock frequency of the target device. ISP frequency should be less than a quarter of the clock frequency of the target AVR microcontroller.

6.Next, go to the Tools tab and click ‘Add target’. In the window that appears select ‘STK500’ and ‘the virtual COM port 3’.

7.Then go to the Tools tab again and press ‘Programming the device’.

8.In the window that appears, where the tools are, select ‘STK500 COM port 3’. As a device for programming, select the Atmega 8 microcontroller. Next, indicate the ISP programming interface.

The ISP frequency can also be set in Atmel studio, but the frequencies specified in the Atmel studio user interface do not match the actual frequencies of the programmer used.

9.Read the voltage and signature of the target device, after which go to the Fuse-bits tab and click on the checkboxes as shown in the video. Record the set fuse-bits in the microcontroller’s memory.

10.Next, open the Memory tab and select the HEX file stored on the computer and also record it in the microcontroller’s memory.

Step 9: Connection the PCB of the LED Matrix and the Control PCB.

After programming the microcontroller and soldering all the radio components, let’s connect the printed circuit board of the LED matrix and the control circuit board.

Step 10: The Work of the 10 Band Led Spectrum Analyzer.

Step 11: End of Instruction

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