Uploaded June 2021 | Updated September 2026, 3 weeks ago
► $2 for 1-4 Layer PCBs, Get SMT Coupons: jlcpcb.com/DYE
This Vu-Meter with LM3915 integrates an LM386 amplifier and a microphone, so that it can work without having to be physically connected to any audio source. As LED display I used a bargraph (Model: KYX-B10G). The sensitivity of the microgon (GAIN) is adjustable by means of a 10KΩ trimmer placed on the PCB. The Vu-Meter must be powered with a voltage between 5v and 12v DC, and the maximum current absorption is equal to 100mAh. There is also a 1N4007 diode in the circuit which protects the Vu-Meter from short circuits during power supply phase.
● Components:
1x LM3915 IC
1x LM386 IC
1x 10 LED Bargraph (Model: KYX-B10G)*
1x Microphone Capsule
1x 3mm LED (any color)
1x DIP 18 PIN (for LM3915)
1x DIP 8 PIN (for LM386)
1x 1uF Electrolytic Capacitor (25-100v)
2x 10uF Electrolytic Capacitor (25-100v)
1x 100uF Electrolytic Capacitor (25-100v)
1x 10nF Polyester Capacitor
1x 47nF Ceramic Capacitor
2x 1N4007 Diode
1x 50Ω ¼W Resistor
1x 1KΩ ¼W Resistor
3x 2,7KΩ ¼W Resistors
2x 100KΩ ¼W Resistors
1x 10KΩ Trimmer
1x 9V battery Plug (or two PIN/wires)
1x Two PIN for Dot/Bar Mode
1x PIN Bridge with two PIN
1x Trimmer knob (not mandatory)
* I used a 10 Green LED Bargraph (Model: KYX-B10G) but you can use a Bargraph of different colors, as long as it respects the pinouts of this model.
● Equipment:
- Tin Wire (with integrated flux)
- FLUX (extra FLUX if you need to use it)
- Soldering Iron
- Wire cutters
● PCB: (Ready for jlcpcb.com): drive.google.com/file/d/1gua93or_xLqqXsX5O4gPY4L0azWS49jc/view?usp=sharing
*Don't use my PCB for profit or sponsored videos.
● Features:
Range: 30dB (3dB for LED)
Power Supply: 9-12v DC
Absorbed current (MAX): 100mA/h
Weight (assembled): 20g
PCB Layer: 2
PCB Size: 33x67 mm
PCB Thickness: 1,6 mm
Screw fixing holes: 4x 2 mm
Short circuit protection: YES (with a 1N4007 Diode)
Cool design: YES
Adjustable GAIN (by 10KΩ Trimmer)
- About LM3915:
LM3915 is a monolithic integrated circuit that detects analog voltage levels and drive ten LEDs, LCDs or vacuum fluorescent displays, supplying a logarithmic 3 dB/step analog display which can be calibrated logarithmically and is suitable for log measurements as logarithmic bar graph driver.
- About LM386:
LM386 is an integrated circuit containing a low-voltage audio power amplifier.It is suitable for battery-powered devices such as radios, guitar amplifiers, and hobby electronics projects. It can output 0.25 to 1 watts of power and has an impedance of 8Ω
- About 4mm LED:
It is a LED with a diameter of 4 mm, an unusual size. I found this LED on an old board taken from trash. I haven't found any others on the market.. don't worry, you can use a 3 mm LED!
- About Microphone Connector:
The microphone connection pad on this PCB was designed by me to allow the connection of different types of microphone capsules. Just be very careful in respecting the polarity + and - of the microphone.
► PROS and CONS of use a Vu-Meter with mic instead a standard one:
🟢 PROS: Portability, Not physically connected to the Amp, So cool!
🔴 CONS: Less accurate measurement than cable
For any other questions ask me in the video comments:)
✅ Subscribe to my YouTube channel It's FREE!
Chapters:
0:00 - Intro
0:34 - Circuit Explanation
2:03 - JLCPCB Factory
2:25 - PCB Upload
3:05 - Unboxing
3:40 - Start PCB Assembly
6:45 - Assembly Completed
7:00 - Music Test
7:50 - Circuit Diagram
7:55 - END
■▬▬▬▬▬ LINK & Support ▬▬▬▬▬■
✅ YouTube: youtube.com/c/Stefano91ste
✅ Instagram: instagram.com/Stefano91ste
✅ Pinterest: https://www.pinterest.it/Stefano91ste
✅ My STORE: youtube.com/c/Stefano91ste/store
Watch another video =)
● Music Keyboard: youtu.be/ajtR6eDOaQI
● LED Water Level: youtu.be/n9GB0nfwG8s
● Police Light: youtu.be/PtmEqcRbu4w
● Vu-Meter Stereo: youtu.be/l8oUQpGAOCw
● Traffic Light: youtu.be/6iRjZMHVvhs
● Vu-Meter 40 LED: youtu.be/oWB2faToGAA
● Voltage Detector: youtu.be/yRWRsSASQTc
WARNING: This video is only for demonstration. I don't take any responsibility.
Test Music: Elektronomia - Sky High [NCS Release]
( youtu.be/TW9d8vYrVFQ ) - Copyright-free Music
#LM3915 #diyprojects #VuMeter
► $2 for 1-4 Layer PCBs, Get SMT Coupons: jlcpcb.com/DYE
This Vu-Meter with LM3915 integrates an LM386 amplifier and a microphone, so that it can work without having to be physically connected to any audio source. As LED display I used a bargraph (Model: KYX-B10G). The sensitivity of the microgon (GAIN) is adjustable by means of a 10KΩ trimmer placed on the PCB. The Vu-Meter must be powered with a voltage between 5v and 12v DC, and the maximum current absorption is equal to 100mAh. There is also a 1N4007 diode in the circuit which protects the Vu-Meter from short circuits during power supply phase.
● Components:
1x LM3915 IC
1x LM386 IC
1x 10 LED Bargraph (Model: KYX-B10G)*
1x Microphone Capsule
1x 3mm LED (any color)
1x DIP 18 PIN (for LM3915)
1x DIP 8 PIN (for LM386)
1x 1uF Electrolytic Capacitor (25-100v)
2x 10uF Electrolytic Capacitor (25-100v)
1x 100uF Electrolytic Capacitor (25-100v)
1x 10nF Polyester Capacitor
1x 47nF Ceramic Capacitor
2x 1N4007 Diode
1x 50Ω ¼W Resistor
1x 1KΩ ¼W Resistor
3x 2,7KΩ ¼W Resistors
2x 100KΩ ¼W Resistors
1x 10KΩ Trimmer
1x 9V battery Plug (or two PIN/wires)
1x Two PIN for Dot/Bar Mode
1x PIN Bridge with two PIN
1x Trimmer knob (not mandatory)
* I used a 10 Green LED Bargraph (Model: KYX-B10G) but you can use a Bargraph of different colors, as long as it respects the pinouts of this model.
● Equipment:
- Tin Wire (with integrated flux)
- FLUX (extra FLUX if you need to use it)
- Soldering Iron
- Wire cutters
● PCB: (Ready for jlcpcb.com): drive.google.com/file/d/1gua93or_xLqqXsX5O4gPY4L0azWS49jc/view?usp=sharing
*Don't use my PCB for profit or sponsored videos.
● Features:
Range: 30dB (3dB for LED)
Power Supply: 9-12v DC
Absorbed current (MAX): 100mA/h
Weight (assembled): 20g
PCB Layer: 2
PCB Size: 33x67 mm
PCB Thickness: 1,6 mm
Screw fixing holes: 4x 2 mm
Short circuit protection: YES (with a 1N4007 Diode)
Cool design: YES
Adjustable GAIN (by 10KΩ Trimmer)
- About LM3915:
LM3915 is a monolithic integrated circuit that detects analog voltage levels and drive ten LEDs, LCDs or vacuum fluorescent displays, supplying a logarithmic 3 dB/step analog display which can be calibrated logarithmically and is suitable for log measurements as logarithmic bar graph driver.
- About LM386:
LM386 is an integrated circuit containing a low-voltage audio power amplifier.It is suitable for battery-powered devices such as radios, guitar amplifiers, and hobby electronics projects. It can output 0.25 to 1 watts of power and has an impedance of 8Ω
- About 4mm LED:
It is a LED with a diameter of 4 mm, an unusual size. I found this LED on an old board taken from trash. I haven't found any others on the market.. don't worry, you can use a 3 mm LED!
- About Microphone Connector:
The microphone connection pad on this PCB was designed by me to allow the connection of different types of microphone capsules. Just be very careful in respecting the polarity + and - of the microphone.
► PROS and CONS of use a Vu-Meter with mic instead a standard one:
🟢 PROS: Portability, Not physically connected to the Amp, So cool!
🔴 CONS: Less accurate measurement than cable
For any other questions ask me in the video comments:)
✅ Subscribe to my YouTube channel It's FREE!
Chapters:
0:00 - Intro
0:34 - Circuit Explanation
2:03 - JLCPCB Factory
2:25 - PCB Upload
3:05 - Unboxing
3:40 - Start PCB Assembly
6:45 - Assembly Completed
7:00 - Music Test
7:50 - Circuit Diagram
7:55 - END
■▬▬▬▬▬ LINK & Support ▬▬▬▬▬■
✅ YouTube: youtube.com/c/Stefano91ste
✅ Instagram: instagram.com/Stefano91ste
✅ Pinterest: https://www.pinterest.it/Stefano91ste
✅ My STORE: youtube.com/c/Stefano91ste/store
Watch another video =)
● Music Keyboard: youtu.be/ajtR6eDOaQI
● LED Water Level: youtu.be/n9GB0nfwG8s
● Police Light: youtu.be/PtmEqcRbu4w
● Vu-Meter Stereo: youtu.be/l8oUQpGAOCw
● Traffic Light: youtu.be/6iRjZMHVvhs
● Vu-Meter 40 LED: youtu.be/oWB2faToGAA
● Voltage Detector: youtu.be/yRWRsSASQTc
WARNING: This video is only for demonstration. I don't take any responsibility.
Test Music: Elektronomia - Sky High [NCS Release]
( youtu.be/TW9d8vYrVFQ ) - Copyright-free Music
#LM3915 #diyprojects #VuMeter
