    ...()
        .
  q     HC-SR04.
 HC-SR04   -    .
    IIC/I2C/TWI/SPI Serial Interface Module for 1602 LCD Display.
      ATtiny13 (ATtiny13A).
        ECHO.
    40%    2 .
!    HC-SR04    .    R    T
  -  ! .  (good  bad).    ( 
 )   .