This is an improved version of the original design indroduced as a simple audio compressor limiter. The new version includes more features. It offers limiter threshold and compressor ratio adjustments as well as independent release and attack response time adjustments. It has input and output level adjustment potentiometers and there is a digital level indicator for the visual representation of the input, the output and the compression level. There is also a LED to indicate any limiter activity.
Our digital VU meter is based on a microcontroller and it is able to display a stereo bar graph on two LED bars. Although being a digital one, it has analog inputs. The basic idea presented here could be used for building meters to use any kind of digital display.The main circuit board supports LED-bars on dual in-line package (DIP). You may also use discrete LEDs rather than LED bars by assembling a second board that we have designed specifically for this purpose.
This is an FM stereo receiver based on Arduino and the TEA5767 IC. The radio displays information regarding the received frequency, the type of demodulation (monaural or stereo), and the received signal strength. It has a memory capacity of 10 radio frequencies and an additional default frequency definition memory index. The frequency range can be either from 87.5 to 108MHz (US / Europe) or from 76 to 91 MHz (Japan).
We use an Arduino Uno board, a classic 2x16 alphanumeric display, an MCP6022 operational amplifier, some passive components and some lines of code, in order to make a stereo VU-meter. The audio level is displayed logarithmically in two bar-graphs on the LCD.