A dive computer that includes heart rate monitoring capability is provided. The remote control signal transmitted from a remote control apparatus is received, and the controlled apparatus or a second controlled apparatus is selected according to the remote control signal. An image processing apparatus converts the input brightness Linput on the input brightness graph Linput-graph to the output brightness Loutput on the output brightness graph Loutput-graph. Additionally, the architecture enables ad hoc channel access, controlled latency, distance estimation, and distance-directed transmissions. The health service agent software transmits data to a health service data manager identifying the type of client node upon which the agent is installed to permit retrieval by the manager of a health service task list specifying rules and executables applied by the health service agent to an associated client node. The motor mounting lugs are slotted, allowing the motors to be adjusted radially relative to the drive shaft and drive bell ring gear.