Accelerometer-based orientation and/or movement detection for controlling wearable devices, such as wrist-worn audio recorders and wristwatches. A wrist-worn audio recorder can use an accelerometer to detect the orientation and/or movement of a user's wrist and subsequently activate a corresponding audio-recorder function, for instance recording or playback. A wearable device with a vibration mechanism can use this method to remind a user of an undesirable movement such as restless leg movement. Likewise, a talking wristwatch can use this method to activate audio reporting of time when a user moves or orients his or her wrist in close proximity to his or her ear. In such applications, and many others, accelerometer-based control of the wearable device offers significant advantages over conventional means of control, particularly in terms of ease of use and durability.