Batteries Not Included: The Science Of Battery-less Devices

Three emergent technologies promise to change the way our smart devices will work in the future. One thing all three technologies have in common is the repurposing of existing signals that already exist in the air all around us.

1. Wireless devices go battery-free with new communication technique.
Imagine devices that communicate with each other without a power source, yes, with no batteries to power them. This new communication technique, dubbed “ambient backscatter,” takes advantage of the TV and cellular transmissions that already surround us. Researchers built small, battery-free devices with antennas that can detect, harness and reflect a TV signal, which then is picked up by other similar devices. Practical applications could include smart sensors placed in a bridge that monitor the health of the concrete and steel, then send an alert if one of the sensors picks up a hairline crack; text messages and emails in wearable devices, without requiring battery consumption; and smartphones that, when their batteries do die, still send text messages by leveraging power from an ambient TV signal.

2. Renesas creates a near-field wireless communication with no battery use.
Renesas Electronics Corp has announced the development of a Near Field Communication (NFC) technology that can wirelessly transmit data to Bluetooth- and LAN-compatible devices without the use of a battery. The system instead makes use of the electricity generated by environmental radio waves. A module that is equipped with an LC resonant circuit absorbs radio waves through LC resonance.

3. Wi-Fi signals enable gesture recognition throughout entire home.
Imagine being able to control your TV, turn off the lights, skip a song playing on your music system with a simple gesture — without sensors attached to the human body or the use of cameras. This WiSee gesture recognition is achieved by repurposing wireless signals that already exist without needing to deply more sensors. An adapted Wi-Fi router and a few wireless devices in the living room will allow users to control their electronics and household appliances from any room in the home with a simple gesture.