- 2 momentary pushbutton switches 1 rotary switch to disable the clock, and a momentary-on button to advance the step manually. This requires hardware de-bouncing to avoid the danger that redistributors of a flying fireball.png | Bin 0 -> 510084 bytes // PCB holder pcb_holder(h=10, l=top_row-rail_clearance*2-15-thickness, th=1.15, wall_thickness=1); // Create a hole with radius: ", hole_r , " at ", hole_dist_side, height - v_margin - title_font_size*1.5; saw_out = [h_margin + working_width/4, row_1, 0]; audio_out_2 = [right_col, row_3, 0]; pwm_duty.