Building robots at the micron scale is tricky, particularly when it comes to designing small-scale ‘actuators’ – the motors that allow robots to move. Conventional actuators don’t work at such a small scale, and new actuators that do work use mechanisms like magnetism and are difficult to integrate with traditional silicon based micro-electronics. Now a team of researchers have developed a new type of actuator that operates electronically and that can be layered directly onto the circuit that controls it. This opens the doors for the last 50 years of micro-electronics research to be incorporated into robots so small they can’t be seen by the human eye.