One of the best things that can happen to a university is to have a Nobel Prize laureate among its staff or alumni. In the case of the University of Groningen we are happy to have a winner. In 1953 Frits Zernike was awarded the Nobel Prize for physics, because of his invention of the phase-contrast microscope. But the work of Zernike involved more than just this. Much of his work has influenced theoretical physics, but he was also a keen DIY-er and built most of his inventions by himself. I will present some of his more unknown inventions, which had, or did not have, some influence in the world of physics, but are most caught up by time.