LED 7 segments Volume Control
Very often many musical maniacs asks - How to control volume? And please do not suggest potentiometer. Any Ideas?
Yes. One more or yet another metod (1000 times was discassed before) - relay method.
So, on this web page I only realize digital part of VC. In the internet we can see such method as L-Type. In words - 32 or 40 relais or even more relais one by one connect proper resistor in the net from input signal to output. All other resistors are from output to ground. This way we can change output voltage.
Usualy we use microcontroller AVR, or PIC, or STM. Led 7seg to dispalay volume. If we make such R-2R VC then we use only one MC port (8bit) to control 6 or 7 relais. But if we make L-Type VC then we must control many relais - 32 in my case. To control so many relais we can use i2c extender - PCF8574 (8bit) or MCP23017 (16bit) and some others. Its not so hard to understand i2c bus to control - earlier VC I was made with Nixie is here
: : Preamp : :
But if you have less experience or you are beginner then you can use simple ideas and simple methods to control volume. In any way we can use MCP23017x2 or we can use 74154 IC (k155id3 in the exUSSR). The difference between 2IC is that MCP output we can control with "0" or "1" as we wish, 74154 output only "0". And 2 more ex USSR ICs we use 514id2 to display volume on 7 SEG. Download zip (found in the internet) for proteus to emulate. We use encoder here co control volume. Proteus model uses 2 buttons.
: : Proteus model for 7SEG VC : :
: : Source BAS-File for 7 SEG VC : :
: : 514id2 Proteus LIB : :
: : Test board video : :
Nixie Volume Control
Same method we use here but with significant replacement and addition. We cange 514id2 by 74141 (155id1 ex USSR) and 7 SEG led indicators by nixie tubes IN-14 for digits and IN-19V for "-" and "db" signes. I couldnt find proteus lib files for IN-19 and IN-14 tubes but i found IN-18 lib for proteus. IN-14 and IN-18 works the same the difference only in symbols stile.
