Buttonhole sewing guiding device of a sewing machine

A buttonhole sewing guiding device of a sewing machine which has a sewing needle operative for sewing a buttonhole in a fabric, a presser foot holder for pressing the fabric, and a central process unit, comprising:

• a buttonhole presser foot unit including a presser frame, a button guiding plate adjustably disposed on said presser frame in a front-and-rear direction, and a sliding member movably disposed on said presser frame in the front-and-rear direction, said presser frame having a frame front end portion and a frame rear end portion, said button guiding plate having a plate front end portion and a plate rear end portion and being movable relative to said presser frame in the front-and-rear direction between a non-use position, where said plate front end portion is proximate to said frame front end portion, and a use position, where said plate front end portion is distal from said frame front end portion and spaced apart from said frame front end portion by a gap interval that corresponds to a diameter of a button, said sliding member being detachably connected to the presser foot holder such that said presser frame is movable relative to said sliding member between a first sewing position, where said sliding member is proximate to said frame rear end portion and distal from said button guiding plate, and a second sewing position, where said sliding member is distal from said frame rear end portion and proximate to said button guiding plate;
• and
• a sensing unit including a sensing module which is disposed on said sliding member and which is in signal connection with the central process unit, a first triggering member which is disposed on said presser frame such that, when said presser frame is in the first sewing position, said first triggering member initiates said sensing module to transmit a first signal to the central process unit for controlling operation of the sewing needle in a first mode, and a second triggering member which is disposed on said button guiding plate such that, when said presser frame is in the second sewing position, said second triggering member initiates said sensing module to transmit a second signal to the central process unit for controlling operation of the sewing needle in a second mode.