Generally, the integrated circuits used for vumeter indicators support 2×15 LEDs or 10 LEDs. In this circuit, more LEDs are used using the Atmel microcontroller. The Vu-meter circuit is based on the Atmega8 microcontroller, there are two channels, stereo, 32 LEDs per channel, a total of 64 LEDs. There are PCB drawings, hex and c codes.
The connection diagram is very simple. There is a 5V stabilizer on the upper right. If you have a direct stabilized 5V 400mA, you can skip this part, but this connection will mostly be used in our amplifiers that are not stabilized 5V. A heatsink must be placed on the 7805 stabilizer. The size of the heatsink is determined by the supply voltage, if you feed the connection with a voltage up to 12V, it will lose a maximum of 3W, a relatively small heatsink is sufficient for this.
However, at higher supply voltages, it is better to wire the stabilizer and place it on a large heatsink. Below the stabilizer in the diagram, there are audio input switchers for the A/D converters on the microcontroller. You set the required sensitivity for the input signal on the R1 and R2 trimmers.
On the bottom right, there are transistors that quickly switch individual columns of LEDs. And on the left, there are the LEDs themselves. Thanks to the internal resistance of the microcontroller, which limits the current to about 80mA, the LEDs do not need to be connected through any limiting resistors, and the fast switching of the 4 columns of LEDs creates PWM modulation, allowing a current of about 20mA to enter one LED. Below the 2x32LED diodes, there are 2 more LEDs that are constantly on and serve as power-on indicators. In the middle, there is the microcontroller itself with C3, which minimizes the noise of the A/D converter.
The LEDs flash at a frequency of about 100Hz to minimize audio interference, but this frequency can be increased by software to 20kHz, but when disconnected from the audio source, a soft whistling sound can be heard in the amplified audio.
Atmega8 LED VU Meter Circuit
hawelson.blog.cz/1005/vu-metr-2x32led-s-mikrokontrolerem
Password: 320volt.com
Published: 2010/08/03 Tags: atmega8 projects, avr project, led projects, microcontroller projects
From matchbox drawer for electronic materials
Electronic materials, plastic drawers for components, but many of us are using plastic = oil / dollar relationship because their prices are too high drawer material.
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Resistance, potentiometer etc. for z description of matchboxes (117) placed in the bottom drawer plastic parts made with dry matches easily have provided the opening and closing