This paper describes the design, development and succesful use of an on-chip goniometer for room-temperature macromolecular crystallography via acoustically induced rotations. We present for the first time a low cost, rate-tunable, acoustic actuator for randomised in-fluid sample orientation and its utilisation for protein structure determination on a synchrotron beamline. The device enables the efficient collection of diffraction data via a rotation method from a sample within a surface confined droplet. This method facillitates efficient macromolecular structural data acquisition in fluid environments for dynamical studies
