for informing the operator when the amount of thread remaining on the bobbin falls below a predetermined threshold fig3 is a system block diagram of circuitry for controlling the illumination of the indicator 61 in response to the amount of thread remaining on the bobbin 30 referring to fig3 and 4 of the drawings a microprocessor 70 is shown which has for one of its primary purposes the control of a matrixed group of led 39 s 71 to display for the sewing machine operator the form and proportion of stitch pattern as it will be produced in accordance with the setting of the various sewing machine controls the u s pat no 4 341 170 july 27 1982 of beckerman et al may be referred to for a more complete disclosure of a microprocessor controlled matrixed group of led 39 s for display purposes however for purposes of the present invention it will be sufficient to understand that inputs 72 are provided to the microprocessor from the sewing machine stitch pattern memory display instructions for each stored pattern in the stitch pattern memory and from the various operator influenced controls on the sewing machine the microprocessor delivers output controlling drivers 73 and 74 to the matrixed group of led 39 s 71 with this arrangement the led 39 s are multiplexed at.