Defects in diamond, such as the nitrogen-vacancy (NV) centre possess optically-addressable spins with long coherence times at room temperature and offer an intriguing system to examine quantum spin dynamics coupled to a macroscopic classical particle. In this work, we convert the outcome of a quantum measurement on an ensemble of spins into a macroscopic rotation of the host particle. Following a sequence of green laser and microwave control pulses, spin-mechanical coupling between the final qubit spin state and the host particle – an electrically-levitated diamond – exerts a torque on the particle that deflects a weak near-infra-red laser beam. We measure spin readout contrast in excess of 70%, and demonstrate pulsed mechanical detection of coherent Rabi oscillations, spin-echo interferometry and T1-induced relaxation. We directly measure with temporal resolution the particle reorientation from a 50 attonewton-metre spin torque induced by a spin flip. I will discuss recent improvements and enhancements to our experimental system that allow for spatial mapping of spin-torque contrast, coupling between multiple trapped particles and schemes for in-vacuum loading of microdiamonds. I will also present results on our attempts to use core-shell nanodiamonds in optical trapping experiments to circumvent uncontrolled nanoparticle heating.