Electronic devices are getting smaller and smaller and human workers and conventional robots are finding it increasingly difficult to assemble them. Peter Will of the Information Sciences Institute (ISI) of the University of Southern California and his collaborators at the California Institute of Technology have designed microrobots modelled on hairlike cilia, the transport fibres of bacteria. Will's team has made arrays of several hundred microrobots each of which has a hairlike arm capable of whipping in one direction only. These arms, at present, are capable of transporting chips in a 2.5 micrometre range. "They are also working on programmable arrays so they can change the direction in which they propel the cargo. Will eventually will try to build intelligent microrobots by connecting each to a photocell. "This will enable the robots to recognise parts and determine whether they are correctly positioned," he says.