A condition of an unmanned aerial vehicle (UAV) is detected using one or more sensors of the UAV and signaled according to an alert definition associated with the condition. For example, an alert definition can indicate to signal the condition by using a motor of the UAV to produce an audible tone. A tonal signal having a frequency within an audible spectrum can be generated according to the alert definition. The tonal signal and a drive signal used for supplying current to the motor can be combined to produce a combined signal. The combined signal can then be transmitted to the motor to cause the motor to produce the audible tone. In some cases, an amplitude of the tonal signal can be modulated, such as where the amplitude of the combined signal exceeds a threshold associated with an operating margin of the UAV.