Smartphone remote control for home automation applications based on acoustic wake-up receivers

In most home automation scenarios electronic devices like shutters or entertainment products (Hifi, TV) are constantly in a standby mode that consumes a considerable amount of energy. The standby mode is necessary to react to commands triggered by the user. To reduce the standby current we present a node that can be attached to the plug of electronic devices and that can turn them on and off. The node contains a wake-up receiver module that reacts to an acoustic 18 kHz tone and that switches the node from active to passive mode. In active mode the node can turn on or off the respectively power source for the device under control. The acoustic wake-up signal can be sent out by any kind of speaker which enables a commercial smartphone to act as an universal acoustic remote control without line-of-sight requirement. Our wake-up receiver consists of an 18 kHz LF receiver and an MEMs-Microphone. A wake-up range of 7.5 m using a smartphone as a sender was achieved. The overall power consumption was measured to 56 µW in standby mode. Using a 230 mAh coin cell as the energy supply a theoretical lifetime of 500 days is possible.