Here’s the new module from @HAGIWO 
DIY eurorack modular synth Noise & Hi-hat with easy VCA circuit and arduino
My 13th original eurorack modular synth DIY projects with arduino.
Digital noise module with high-speed random PWM.
By controlling the transistor VCA with the PWM decay waveform by arduino, the sound of the hi-hat is output.
I used to play the hi-hat on a $ 300 erica synths sample drum, but now I can play it for only $ 5.
working documents ( Source code )