Introduction: Big VU Meter on Incandescent Lamps 220 Volt.

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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 tell you about the audio level indicator on 220 volt incandescent lamps.

Step 1: YouTube Video

Link to this video:

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:

Links to radio components:                                                             

Radio parts store:

Microchip LM324:

Microchip LM311:

Microchip LM358:

Triak BT137-600E:

Optothyristor MOC3021:

Transformator 230В/9В/5VA 1:

Transformator 230В/9В/5VA 2:

Mounting racks:

Step 3: Circuit Design and PCB Layout.

The schematic diagram of the audio indicator consists of three parts, such as: a microphone amplifier, a power unit and adjustment, a linear indicator with power amplifier stages.

This device operates in such a way that after amplification and smoothing the microphone signal is converted into a voltage with a level proportional to the signal amplitude. This voltage is applied to a number of comparators each of which drives a symistor.

The main unit of the regulator is a sawtooth generator which is synchronous with the mains voltage. With its help a command to turn on the symistor is generated, and if there is a comparator signal, power is applied to the lamp of the column.

Step 4: Choke Manufacturing.

Now let’s manufacture an antijam choke.

We need an enamelled copper wire with a diameter of 1 mm, a length of about 1.350 mm and a toroidal core made of powdered iron with an outer diameter of 30 mm and an inner diameter of 20 mm.

We need to wind 38 turns of copper wire around the toroidal core.

We can apply the load up to 1000 watts with the help of such a choke.

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

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

Step 6: Configuration of the Circuit Control Board.

After installing all the radio components, you need to configure the control circuit board.

Using a digital multimeter with limits of measurement of 20 V (DCV), adjust the variable resistor Aj1 so that the voltage measured on the capacitor C3 is about 2.9 volts.

Next, using the variable resistor Aj2 you need to set the maximum actuation level of the upper lamps so that they light up at the maximum sound level.

Step 7: 3D Visualization.

To create 3D visualization and drawings of the audio indicator body, the KOMPAS 3D program was used. The body of the device consists of 8 parts. 3 mm transparent organic glass was used to manufacture them. All drawing files were converted to DXF format and sent to a sheet cutting company.

Step 8: Assembly of the Control Circuit Board With the Bottom Panel.

Insert brass posts M3 6 mm long into the holes of the control circuit board and fix them using nuts.

After that, put the control circuit board and the bottom body panel together using screws M3.

Step 9: Wires Preparation for Connection.

Next, prepare the wires for the further connection of the incandescent lamps with the control circuit board.

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

Step 10: Installing the Incandescent Lamp Holder.

To install incandescent lamps we will use a common holder with an adapter plug of European standard E27 made of heat-resistant white plastic.

Before installing the holders on the inner edge of the body, you need to remove the top protective cover.

Insert the screws M3 into the through holes of the holders for incandescent lamps and fasten them from the back side using nuts.

Step 11: Installing the Middle and Upper Panels on the Inner Edge.

Install the middle and upper body panels on the inner edge. Insert the nuts into rectangular holes from the end sides. After that, put the parts together using screws M3.

Next, mount one of the side panels on the middle edge.

Step 12: Installing the Bottom Part With the Control Board on the Side Panel.

Insert the assembly of the control circuit board and the lower part of the body in the through rectangular grooves on the side panel.

After that, install the second side panel.

Step 13: Installation of Wires Into Spring Contacts of Lamp Holders.

Mount the wires into the spring contacts of the lamp holders through the holes on the inner edge of the body.

Step 14: Installing Wires From Each Individual Level Into Terminal Holes.

Insert the wires from each individual level of the audio indicator into the terminal holes on the control circuit board fixing them with screws.

Step 15: Wiring Power Connector With Rocker Switch.

Connect the power socket to the rocker switch using wires and install it into the holes on the back side of the body.

After that, let’s fix the back panel.

Step 16: Installing the Front Panel.

Next, mount and fasten the front panel with other body parts.

Place decorative handles with an inner diameter of the axis of 6 mm on potentiometers.

Step 17: Installation of Colored Incandescent Lamps.

Next, screw 25-watt colored incandescent lamps into the holders. Take into account the total load power when choosing the fuse F1.

Then turn the wipers of potentiometers P1 and P2 to the right until they stop. After power supply connection, several lamps should light up, especially if the ambient noise is significant.

If the brightness of the lamps decreases when you slowly turn the potentiometer handles P1, the regulator operates properly.

Then you need to adjust the sensitivity of the microphone using the potentiometer P2.

Step 18: Work Result.

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