Every wanted to make your mBot draw perfect squares, triangles or any other polygon? This holder is designed to keep a drawing instrument exactly between the robots wheels. So nothing gets drawn when you are turning. Now you can write programs to draw shapes with your kids.
-- Mounts under your mBot using four screws into the metal frame. There should have been some extra screws when you got your mBot which work perfect.
-- The holder snuggly fits a 1cm drawing instrument after cutting it down to size. If you want you can cut a slit between the base and the smaller half of the holder. Then after drilling a hole in the tab you have an adjustable drawing instrument holder. I tried printing this but it took too much support structures and was easier to drill out.