Ultra-low-power Bluetooth devices might eliminate need for batteries
The Bluetooth 5 standard was designed primarily to share information between devices within the confines of the home or a car and in a workplace. That said, the new version of Bluetooth has properties that should make it attractive for some Internet of things applications. Atmosic Technologies is focusing on low-power Bluetooth 5 wireless platforms to enable networks of IoT devices that are, as the company says,"Forever Connected, Anywhere."
The new Bluetooth 5 offers performance improvements over legacy Bluetooth of four times the range, twice the speed, and eight times the bandwidth. Bluetooth 5 extends the functions that were already provided by the previous versions and aims at greater flexibility and interaction between the network-connected devices.
What might link Bluetooth 5 to the IoT at large is the presence of Bluetooth in smartphones and tablets. Many IoT applications require a long-range but minimal bandwidth capacity, transmitting data only intermittently. Bluetooth stands as an alternative for other IoT applications, offering mesh networking that can include a large number of nodes. Bluetooth 5 can guarantee a decentralized system of devices without having to resort to a single controller hub – a real peer-to-peer communication network in which the nodes are equivalent or, better, equal. Different products will be able to interact and work together.
The Bluetooth 5 standard also gives special attention to connection security. This is mainly done to avoid interference with other wireless devices connected to the network and thus facilitate the use of IoT applications.
By 2023, there will be over 30 billion Bluetooth-enabled devices worldwide, with a growing percentage destined for IoT applications.
Atmosic, with its RF CMOS design, focuses on a vision of low-power IoT applications that might not even have batteries, thereby avoiding problems related to battery life.
Dropping batteries will have a strong impact on costs and maintenance (Figure 1). The growth and evolution of Bluetooth systems is surely linked to the growth leading to the IoT industry in these years and in the coming years.
Figure 1: improvement in battery life with Bluetooth 5 [Source: Atmosic]
“If you hate changing batteries, you’re going to like the technologies we’re developing to help eliminate that problem,” said John Hennessy, advisor to Atmosic and chairman of the board of Alphabet. “The Atmosic team is applying its extensive wireless and low-power expertise to bring innovative radio and energy-saving designs to market. Our mission is to redefine battery life.
Many of the IoT end points powered by batteries make them truly “wire free” solutions. However the opportunity cost of replacing batteries frequently is significantly more than the cost of battery. Having battery-free or forever battery life solutions greatly eliminates the recurring operating and opportunity costs, said Srinivas Pattamatta, VP of Atmosic.
Atmosic has developed three innovative technologies: Lowest Power Radio, On-demand Wake-up, and Controlled Energy Harvesting. The first is aimed at solving the energy and management challenges of IoT devices such as beacons and fitness trackers. Atmosic's controlled energy harvesting brings a new level of battery performance.
Figure 2: Atmosic Bluetooth 5 ultra-low power single chip [Source: Atmosic]
The Atmosic M2 series solutions are compliant with the Bluetooth 5 standard and improved with low-power radio and Wake Up on-demand technologies to require 10 to 100 times less power. The M3 series Atmosic solutions have added controlled energy harvesting that allows operation without batteries, thus ensuring battery life or battery-free operation forever (Figure 2 and 3).
Figure 3: Atmosic technology [Source: Atmosic]
By using their energy harvesting solution, the system can generate several tens of milliwatts with an efficiency of 30 to 40 percent, excluding the loss of the RF path.
Various parameters must be evaluated, which can decide the performance of an RF energy harvesting project. Critical parameters such as efficiency, sensitivity, operating distance, and output power are defined as the standard for making relative comparisons. The Q factor is generally defined as a dimensionless value that describes how strong the resonance is. Each antenna has its optimal operating frequency, precisely known as the resonance frequency. The latter is determined by the capacitance and inductance characteristics of the antenna. The capacity and inductance of an antenna are functions of the frequency and physical size of the antenna itself. The larger the antenna size, the lower the resonance frequency. The bandwidth of an antenna is the frequency range in which the antenna can work efficiently. Narrowband antennas offer excellent conversion efficiencies but can only recover a limited amount of energy.
Energy harvesting can use several environmental sources and provides an unlimited operational life for low power equipment, thus eliminating the need to replace batteries which is expensive and impractical in many IoT applications. The possibility of radiofrequency energy harvesting therefore offers space to the general concept of collecting RF energy from both internal and external environment, of any characteristic in the range of radio frequencies and in the energy range whose limits are set only by the natural threshold of thermal noise and the performance of the collection device.
>> This article was originally published on our sister site, EE Times:"The Next Wave of IoT Bluetooth Devices Might Not Have Batteries."