Abstract: Methods support a sleep mode for an embedded device. Embedded devices like sensors and actuators used in wireless sensor networks have a limited power supply. To conserve energy and thus increase the lifetime of these devices, the devices should be put into a stand-by mode (also called sleep-mode) when they are not used. These methods support the sleep mode at a higher level than the MAC layer, thus avoiding the problems of prior art approaches. Methods are exemplarily described for the case of the message queuing telemetry transport protocol for sensor networks. They can easily be adapted to other protocols.

Abstract: A method and apparatus for fast charging of batteries such as lead acid batteries is provided. A repeatedly pulsed current is applied to the battery to enable a determined resistance free maximum pulsed voltage to be reached where the determined resistance free maximum pulsed voltage is below that at which unacceptable gassing will occur. The determined resistance free maximum pulsed voltage is above that of a known average resistance free pulsed voltage for the battery type. When the determined maximum pulsed voltage is reached the pulsed current is continued to be applied to maintain the resistance free maximum pulsed voltage at approximately the determined resistance free maximum pulsed voltage by at least one of: (I) reducing the amplitude of the pulsed charging current, (II) increasing the OFF-time of pulses of the pulsed charging current, (III) decreasing the ON-time of pulses of the pulsed charging current, (IV) a combination of any two or more of (I), (II) or (III).