Abstract: In some implementations, a user device can coordinate adjustments to a composite GUI generated in cooperation with an accessory device that presents the composite graphical user interface. For example, the user device can receive configuration data that defines the maximum GUI display area (e.g., size, dimensions) of the accessory device, various view areas within the GUI display area of the accessory device into which the user device can render GUIs, and/or transitions between the various view areas. The user device can generate a display buffer based on the maximum GUI display area, generate a graphical user interface in an area of the buffer corresponding to a current view area specified by the accessory device, and send to the accessory device video frames corresponding to the display buffer. The accessory device can generate a composite GUI based on the received video frames that include the user device generated GUI.

Abstract: A speed control arrangement for a rotatable member driven by an energy source, such as a spring, whose driving torque can vary consists of an eddy current brake comprising an eddy current rotor driven with the rotatable member and a magnetic circuit coupled to the rotor to exert a braking effect. The magnetic circuit is carried by an arm movable relative to the rotor by unwinding of the spring (or other change in torque) to alter the coupling, and the braking effect, as the torque exerted by the energy source varies.