This project would be a bit difficult for someone new to electronics projects but interested in it. 5.Make your LEDs Dance to Music!ĭrZzs’s video shows how to make a disco room, letting the LED dance to the music. Ms Mad Lemon worked on the moving coil VU Meters. 3.DIY Music Reactive LED Strip VU MeterĬreative creator once made a video to show how to make DIY Music Reactive LED Strip VU Meter with WS2812B addressable RGB LED. Hayri built a Stereo VU Meter, the code is written by Greg Stievenart. It’s RH Electronics’s completed Analog VU driver and meters for his amplifier project. Normally, we’ll see VU meters like this one. ![]() So today we are going to talk about our PCBWayer’s amazing VU meter projects! 1.Analog VU Metersįor complex waveforms such as speech, a VU meter reads between the average and the peak values of a complex wave. Such meters employ special ballistics that averages out complex waveforms to properly indicate program material that varies simultaneously in both amplitude and frequency. But the LM324 has all kinds of problems.A VU meter is used to measure the power levels of audio frequency signals. Then when the input to R9 goes positive the base-emitter of the transistor is turned off and C8 discharges into R13.Ī lousy old LM324 quad opamp can replace the much better MC33171 opamp I used or you can use MC33174 quad opamps. The 100k resistor from the transistor's emitter to the - output of the opamp is the negative feedback so that a negative voltage to the input resistor R9 causes the opamp and transistor's emitter to go positively charging C8 through R12. ![]() The transistor in my peak detector is the rectifier and it provides a much higher current than the opamp can to quickly charge the attack/release timing capacitor. The opamp I used works fine when its inputs are as low as 0V with no negative supply. So it always needs its inputs fairly far above 0V if it has no negative supply. TL07x opamps have a problem (Opamp Phase Inversion) that the output suddenly goes as highly positive as it can when its input voltages get within a few volts from its negative supply. So far, all of the components listed in your suggestion are in my parts drawer (aside from the MC33171). Or I could task that job to the T元24, providing it's up to the task. It is feasible to enable a separate TL074 op amp for the peak detector, using only + & ground as supply voltages (if that's possible) and keep the band pass filters on a separate dual voltage supply, could that work? I have several of them. You're saying that linking in the transistor's emitter (thru R8 - 100k ohm resistor) back into the op-amp's negative input kills the negative swing of the sine wave function, turning it into a half wave peak detector? Replace which transistor? The one inside the peak detector? Or the one driving the lights? I don't understand. For what it's worth, I don't (& wouldn't) tie in the -15v supply voltage as ground, nor enable it with the audio ground input, I'm no expert, but I'm pretty sure that would toast the radio that's supplying the audio input signal. Is it possible to use a TL074 with a + & a ground to supply the power? I thought that because it was dual rail it needed + & - supply voltages. (Yes, I have a 15v +/- dual power supply module for the split rail TL074s). If I were to include bandpass filters into this circuit, would you recommend placing them prior to the peak detector, following the detector but before the transistor amplifier, or following the amp? I have a spare pair of op-amps on the chip, no reason why I shouldn't use them. Since it's stereo (left & right channels each get their own set of lights), it's easy enough to use a multiplex op-amp.ģ. Could I use a TL074 or an LM328 instead of the MC33171? Because that's what I have available for my bandpass filters. If I decreased the values for these components, could I quicken the release response?Ģ. Would I be correct in assuming that C8/R13 in your circuit are responsible for the slow decay rate on your peak detector? I've toyed with the cap values on the LED string, anything higher than 47uF gives me a sluggish decay, less than that and it flickers noticeably. ![]() Click to expand.Audioguru, a few questions:ġ.
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