Abstract: This invention discloses a method of using a cloud server to remotely detect the status of a home automation gateway of a home security and automation network. According to this invention, the home automation gateway of the home security and automation network periodically sends heartbeat packets to a cloud server. The cloud server monitors the reception of all these heartbeat packets, records relevant information contained in these heartbeat packets in a database, and updates the most recent status of the particular home automation gateway. If the cloud server has not received any heartbeat packets from the home automation gateway for more than a predetermined time period, the cloud server considers the home automation gateway currently offline and notifies the user of the home security and automation network by sending a notification message to the user's mobile device.

Abstract: This invention discloses a method implemented on a cloud server which issues a unique device serial number to be assigned to a network device (e.g., a WPAN gateway, smart home device). Among other things, the unique device serial number contains a cloud server identification portion which uniquely identifies the issuing cloud server. When the network device is powered on, a identifies the cloud server based on the cloud server identification portion of its device serial number and tries to connect with the cloud server. Upon receiving such a connection on request, the cloud server checks whether the network device's device serial number was one it issued previously. If yes, the cloud server allows the connection. Otherwise, the cloud server denies the connection.

Abstract: This invention discloses a power saving method for battery-powered Zigbee devices. When a Zigbee device loses connection with a Zigbee network, it will search for the Zigbee network until it finds and rejoins the network. However, the Zigbee network may not be available for a sustained period of time due to a long power outage. To avoid wasting the battery power of the Zigbee device on performing too many searching operations, the Zigbee device waits for a waiting period after performing a search operation and before performing a subsequent search operation and the waiting period prior to each subsequent search incrementally increases while more subsequent searches are performed.

Abstract: This invention discloses a power saving method for battery-powered Zigbee devices. Under normal circumstances, a Zigbee device keeps its RF module in sleep mode. Only when the Zigbee device receives a signal generated in response to a sensor triggering event, a user input, or a prescheduled event, would the Zigbee device wake up its RF module to communicate with a Zigbee coordinator. As such, the Zigbee device does not need to always listen to the Beacon signals periodically broadcasted by the Zigbee coordinator, therefore saving a lot of battery power.

Abstract: A rear projection display apparatus for displaying an image reduces parallax error. The display apparatus includes a housing, a transparent screen support having top and bottom surfaces, a translucent display screen removably adhereable to the top surface of the screen support, and a projector to project the image onto the display screen. Optionally, a series of mirrors may be provided to sequentially reflect the image from the projector onto the display screen. In a preferred embodiment, the housing is pivotally mounted on a base, and houses the display screen, screen support, mirrors and projector.