qr_size = 54;
qr_height = 2;
linear_extrude(height = qr_height){
- square(qr_size, center = true);}
+ difference (){
+ square(qr_size, center = true);
+ square(1.5, center = true);}}
translate([0, 0, qr_height]){
motor_shaft_holder(shaft_radius,
shaft_flat_width,