This project is where I try to combine the LED color organ with the VU meter.
The color of the LED depends on the frequency of the audio signal.
Number of rows (i. e, arcs)
Depending on the amplitude of the input audio signal.
This project uses Arduino pro mini, LM358 op-
Amp, mosfet that everyone can easily access.
Watch the video and see if the project is running.
Please use the headphones for clarity.
Please ignore my video making skills.
Here is a list of all the components and things you need to build this project.
Electronic components: 1.
Co-cathode RGB led (x72)2. P-Channel MOSFET (x3)3. N-Channel MOSFET (x5)4. UF4007 diode (x3)5. NPN Transistor(x3)6. LM358 op-amp ic (x2)7.
1k ohm resistance (x8)8.
10k ohm resistance (x11)9.
Resistance 100K Ohm (x3)10.
68K ohm resistance (x2)11. 10K trim pot (x3)12. 200K trim pot (x1)13.
1uF electrolytic capacitor (x1)14. 4.
7uF electrolytic capacitors (x2)15.
10nF ceramic capacitors (x3)16. 6.
8nF ceramic capacitors (x2)17.
68nF capacitor (x1)18.
100nF capacitor (x2)19.
7805 regulator (x1)20.
Screw terminals 1*02 (x2)21.
AUX female pin (x1)22.
DC Jack mother (x1)23.
Arduino Pro Mini (x1)24. PCBs25. 8 DIP base(x2)26. Female headers.
Other materials: 5mm plywood (
240mm * 240mm)
Frosted/transparent acrylic 3mm (110mm * 180mm)
M3 metal gasket 40mm (*2)and 10 mm(*4)
M3 nuts, bolts and washers.
At first I started the building by making the LED logo.
I created the PCB design using the free EasyEDA software and ordered the PCB from the JLCPCB service.
You can access the PCB files here.
If the link to the PCB file does not work.
Please click on this link: I weld the pcb to it.
The gap between LED pads is very small.
So it may be a bit difficult to weld them.
I suggest you do it the way I use it. i.
Insert the LED pin completely into the hole. ii.
One of the end pins of welding poles. iii.
Heat the welded pins and position the LED correctly. iv.
Trim the excess length of all pin leads. v.
Finally, weld all pins with a minimum of welding leads. (
See picture for better understanding).
The work of the drive circuit is very simple.
The circuit consists of four operation units.
Three of them are used as active filters and the other as an amplifier for non-active filters
The filter circuit provides the frequency data to the arduino.
The non-inverted amplifier provides the amplitude data of the audio signal to the arduino.
The Arduino controls the led through the mosfet after receiving the data.
Schematic diagram can be accessed from here: make the circuit according to the above circuit using 2 point pcb.
I built a filter circuit on a small PCB.
Then I built the remaining circuit on a board.
This is a very simple build.
Arduino mosfet led driver: Led driver circuit from 5 n-
3 p-channel mosfetchannel MOSFET. N-
The channel mosfet is connected to the common cathode of the LED.
5 of them are connected to 5 different led lines.
These MOSFETs are just used as switches and the switch will be on if the gate pulls high. The 3 P-
The channel mosfet controls the brightness of the red, green, and blue LEDs. Since P-
If the gate is pulled low and the channel is going to be on, a pnjunction transistor is used to drive these MOSFETs.
The PWM output of the Arduino controls these MOSFETs.
Vcc2 adjustment: voltage control resistor gate when the behavior of the mosfetto-
The supply voltage is less than its clamp-off voltage.
This characteristic of the Mosfet is used to control its brightness by adjusting the current through the LEDs.
VC1 is the voltage power supply to the entire circuit.
This voltage must be greater than 7. 5v.
The input voltage is connected to the input of the buck converter and its output is considered vcc2. 1.
Connect one of the PWM pins (
R _ pwm, g _ pwm, or B _ wm)
Set Vcc2 to 5 v. 2.
Connect the led to the drive board. 3.
Measure the current consumption of led (
Make sure only one color is turned on). 4.
Adjust Vcc2 now so that the current drawing is 250 mA (
Make sure that Vcc2 does not exceed 4. 5v).
The voltage I get for Vcc2 is about 4. 2v.
The voltage is set to a p-
Channel mosfet can be provided to LEDs.
Filters are circuits that allow signals of a specific frequency range to pass through them.
Low pass, high pass and band pass are several types of filters.
Basically, there are two types of active and passive filters.
Passive filters are only a combination of resistors and capacitors (
Call RC network frequently).
Among them, the active filter is composed of RC network and Op-amp.
The number of RC networks is often referred to as the number of poles.
There are many types of active filters whose frequency response curves are shown in the figure above.
Of all types of active filters, the chibisevf filter appears to have a good frequency response.
So I chose this filter circuit for my project and calculated it according to the table given.
Reference: version 3rd of electronic art.
Formula: Formula for cutting-
The Off frequency is from, fc = 1 /(2*pi*R*C*Cn)
Where is the fc cut off
Turn off frequency in Hz.
R is an ohm resistor.
C is the capacitor in farads.
Cn is a factor that depends on the type of filter we use, equal to 1.
Gain of Op-
The amplifier should be K = 1.
842 I chose R as 10k ohm for the chipzig filter.
Therefore, trim basin R6, R13 and R20 should be adjusted (K-1)R = 8.
42K Ohms in the drive circuit.
Low-pass filter: low-pass filter allows signals with a frequency less than the cut-off frequency
The filter circuit passes through its frequency.
Amplitude v/s frequency diagram of low-pass filter output.
Based on the formula given above, I chose R1 = R2 and C1 = C2 as 68K ohms and 10nF.
This gave the cut.
The frequency is 190 Hz (approx. 200 Hz).
High pass filter: high pass filter allows signals with a frequency higher than the cut-off frequency
The filter circuit passes through its frequency.
The output of the Qualcomm filter is shown in the above figure.
I use the same formula again to select R1 = R2 and C1 = C2 as 10k ohms and 6. 8 nF.
This gave the cut.
The frequency of shutdown is 1. 9 KHz(approx. 2kHz).
Band-pass filter: the band-pass filter is a combination of low-pass and high-pass filter circuits.
Band-pass filter circuit has 2 cuts-
Upper limit of frequency (fh)and lower(fl).
Output of the band-pass filter as shown above.
The low-pass part of the band-pass filter determines the upper cut-
The off frequency and the high pass section determine the lower cuttingoff frequency.
Use again the same formula and R1 and C2 as 10k ohms and 6.
We got the cut.
The frequency of shutdown is 1. 9KHz.
Again with R2 = R3 and C1 for 10k ohms and 68 nF, we got a lower cut
The turn off frequency is 190Hz.
This makes it possible to allow the signal at 190Hz-1. 9KHz(approx. 200Hz-2kHz).
Peak detector circuit: the peak detector circuit is just a diode whose anode is connected to the input and the cathode is connected to the capacitor.
The other end of the capacitor is grounded.
The output of the peak detector passes through the capacitor.
Discharge the capacitor using a resistance of 100K Ohm.
The capacitance value determines the sensitivity of the peak detector.
The smaller the capacitance, the lower the sensitivity.
Therefore, there should be fewer capacitors for high frequency, andversa.
The output of the filter circuit is fed into the peak detector and its output is connected to the arduino.
The work of this circuit is very simple.
Initially, when the capacitor is fully discharged, it charges to the peak voltage through the diode and slowly discharges through the resistor, giving the peak voltage as the output until it discharges to a voltage equal to the input voltage, and start charging again.
This cycle is repeated.
In this video you can understand it in more detail: I wrote the arduino code using the arduino IDE and it should be installed before uploading the code.
The code is simple. First we declare all the pins and then assign their readings to the corresponding variables.
Then, in the main section, we set all the output pins to low and start the serial monitor.
Still, in the loop section, we\'re going to start with the op-amps.
After reading, the reading will be printed on the serial monitor.
Then you constrain the reading and map it to a value between 0 and 255.
The value is then used as the PWM output of the corresponding color.
In the code, I set the low frequency to red, the low frequency to green, and the high frequency to blue.
Before that, you can enjoy the final result that some adjustments have to be done.
To do this, you must follow these steps.
Connect the arduino to the USB and the AUX pin to the audio output of the device. 2.
Open the serial monitor on the arduino IDE (
After uploading the code
On-line tone generator (link below).
Play music with a large volume and set the frequency to 100Hz.
After doing so, adjust the R3 trim pan to make the reading low
Freq becomes the maximum value (approx 500 -700 for lm358 ). 4.
Set the frequency to 200Hz and adjust the same fine tuning again-
Low reading pot
Freq 160-close170. 5.
Set the frequency to 10 KHz and adjust the R15 trim pan for high reading
Freq becomes the maximum value (approx 400-700). 6.
Set the frequency to 2 kHz and adjust the same trim pan for high-
Freq 150-close170. 7.
Set the frequency to 1 kHz and adjust the R9trim-
Such a pot, in the middle
The Freq reading is slightly lower than the maximum. (
I have about 200).
Usually less than the other two.
However, this is not an issue I corrected in the code.
If you have any questions about this step, please make them in the comments section.
Tuning R23: R23 is trim-
Pot to adjust the number of rows sensitivity.
It sets the gain of the amplifier, which provides the amplitude data to the arduino.
The tuning of this is very simple, just repeat the steps 1 and 2 given above and set the volume Max at any frequency.
Now you have to adjust the pot so the maximum output of the op-
Amp should be below 710715.
You can adjust the decoration
If all rows are illuminated with small amplitude, or if any of them are not illuminated at all, then the pot will LED Light module
Now that the project is almost complete, it only needs the final shell and wiring.
I made a wiring diagram to make things simpler.
You can wire it according to this.
For the casing I took 2 pieces of plywood of 12*24 cm 5mm.
I applied one side with varnish to make it look smooth.
I then place the LED logo PCB in the center of one of the parts and drill holes for installation.
After that, I welded some wires on the back of the PCB and passed a hole I made in the center of the front sheet.
After doing this, I installed the PCB in its position and then I used some small metal gaskets.
At the top of the spacer I want to install the frosted acrylic sheet but I don\'t.
So, I took a clear acrylic sheet a little larger than the PCB and polished it on both surfaces to make it look frosted.
I then put it on the top of the spacer and installed it.
I repeated the same drilling and installation procedure for the driver circuit and the buck converter to install it on the back panel.
After doing all of these things, I installed the back piece on the front piece with about 40mm metal gaskets.
The case and wiring have now been completed.
Since LCSC is one of the fastest growing suppliers of electronic components in China, this project is possible.
LCSC has been committed to providing numerous, real and in-
Stock project, since its establishment in 2011.
It aims to provide more high-quality products from Asia to the world.
Please visit for more details: I was able to complete this project because of their support.
So, if you make one yourself, I suggest you buy components from them.
I have given the link to all the components above.
If you like this item then please vote for it in the contest. Thank You!
It\'s great to finish this project.
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