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Build Your Own Sound Star VU Meter Kit

A typical VU Meter By Bradley Eckert

Description: Sound Star VU Meter Electronic Kit
Build Time: 1-2 hours
Difficulty: Intermediate (requires soldering)

This is a visual tutorial to help in constructing the Sound Star Volume Units (VU) Meter. A VU Meter is something that tells you visually the volume level of a microphone. A typical VU Meter, shown below, has three colors of LED's, and they will light up from the bottom to the top indicating how loud the noise is, usually from -20dB to +3dB.



This is a good electronics project to practice soldering skills and for some construction fun. It may require some troubleshooting – LED's circuits can be trickyshould work. It was a fun way for me to spend the afternoon and I hope you enjoy it as well.

Empty star board
Finished VU Meter

What you will need:

Sound Star VU Meter Mini Kit
Flat Head Screwdriver
Soldering Iron
Solder Wire
Diagonal Wire Cutter
9V Battery

1. Begin by soldering on all of the jumper pieces – just wires – on the marked paths on the top side of the board.

Star with the jumper cables
Star with the jumper cables
Bottom of star with resistors
Bottom of star with resistors

2. Solder on the resistors, in order from left to right that they come in (left being the side the jumper pieces came on) in the spots marked R1 - R24.

3. Solder on the Diodes and Zener diode into spaces marked. The Diode's polarity line should line up with the line marked on the board in the spaces marked D1, D2 and the Zener in the spot marked ZD1.

Diagram for Diodes
Diagram for Diodes
Diagram for zener diode
Diagram for zener diode


With Diodes and Zener Diode
With Diodes and Zener Diode
Star with LED's
Star with LED's

4. Solder on all the LED's, starting with red in all the spaces marked on the top with the half filled in semi-circle. Make sure the short side of the LED is put into the white filled in side. Next solder on the yellow LED's in the spots marked with a bell shape half filled in vertically. Make sure the short end of the LED is inserted into the flat end of the bell. Next solder the green LED's, in the filled in bell shaped markers, making sure that the short end again is inserted into the flat end of the bell.

Diagram of LEDs
Diagram of LEDs


5. Solder on the transistors in the places marked with T1-T5 and a half circle with three holes. Place the transistor with the flat side facing the flat side of the circle mark, and then put the middle pin into the top hole.

With transistors T1-T5
With transistors T1-T5
Location and position of on-off switch
Location and position of on-off switch

6. Next solder on the on-off switch in to the spot marked.

7. Attach the "trimmer" as shown. This controls the sensitivity of the microphone.

8. Solder the capacitors on in the spaces with a circle marked C1-C4. C1 = 47µF, C2 = 1µF, C3 = 10µF, and C4 = 4.7µF. Read the labels on the capacitors to determine which is which.

Trimmer as it comes
Trimmer as it comes
Assembled trimmer soldered in place
Assembled trimmer soldered in place

Capacitors C1-C4 in place
Capacitors C1-C4 in place
DC connector soldered in place
DC connector soldered in place

9. Attach the DC Connector.

10. Take the two long pins and insert into the two holes inside the circle marked "MIC". Next, solder on the microphone with the side with the flat wire sticking out attached to the negative side. Solder the flat metal to the negative pin.

Microphone in place
Microphone in place
Battery holder in place
Battery holder in place

11. Attach the battery by soldering on the red and black wire to positive and negative, circles marked BAT+ and BAT-, respectively. Then put the black spacers on the two big holes closest to the DC connector and then push the screws through them. Line up the spacers with the battery holder and screw in. Insert 9V battery.

12. Turn on by flipping the on switch. Adjust the Trimmer until the lights begin to flash when the microphone is near music.

Finished Sound Star VU Meter
Finished Sound Star VU Meter

Congratulations! You've completed the project build and hopefully you are excited to take on another project. Check out other kits here.

For more details you can view this product's data sheet.
Brad Eckert grew up in the Bay Area and now attends MIT. He wants to become an engineer and loves to make things and play with robotics.