One challenge in designing nanomachines is being able to establish how well they work and optimize their performance. This is where single molecule techniques will play an important role. With advances in nanotechnologies, it is possible to construct simple nanomachines that can perform simple functions such as opening and closing of a DNA device (e.g. DNA tweezers or DNA switches), small rotational and translational motors and energy transfer cascades. Using single-molecule techniques researchers can watch individual nanomachines working and determine the functionality of their design. Researchers in Germany now have incorporated optical addressability to these nanomachines. Hence, they can optically detect and eventually control the state of the nanodevice.