All posts tagged: low

Today, Internet-of-Things and wireless-sensor networks are finding an increasing range uses of consumer, industrial and medical applications. Such networks often employ a large number of distributed nodes, without interconnecting cables, which can’t practically be connected to the power grid – and it is attractive to keep the need for battery recharging and replacement to an absolute minimum through the use of efficient, careful design choices as well as ambient energy harvesting technology.

Power-efficient wireless sensor nodes can take advantage of some form of energy harvesting power supply, employing energy sources such as solar photovoltaic, vibrational energy harvesters or thermoelectric generators to minimise maintenance and extend battery life – possibly completely eliminating batteries entirely – if the power consumption of the system is small enough and a capacitor is employed for energy storage.

Energy harvesting management ICs that manage the accumulation of energy in a capacitor over a period of time to enable short bursts of relatively high power consumption, such as when a node wakes up and transmits a burst of data, are particularly well suited to low-power wireless sensor nodes.

In many applications, solar photovoltaic are the most familiar choice for low-power sensor and telemetry nodes operating outdoors, for example in agricultural and meteorological applications.

Energy-efficient wireless network nodes can be engineered using modern RF microcontroller system-on-chip devices, turning on and off sensors and peripheral hardware devices when they are not required or putting them into low-power sleep modes when not actively in use.

Similarly, the RF transceiver can be switched into a very-low-power sleep state until the microcontroller decides that a transmission of collected sensor data is required. The microcontroller can then wake up the radio, perform the required transmission, and the radio goes back to sleep.

In some cases, a burst of data transmission across the wireless network might only occur when a small, intermittent energy-harvesting power supply has accumulated enough energy in a capacitor to power a transmission.

With most of the components of the system – the microcontroller, radio and sensors – each kept offline or asleep for the largest practical amount of time, efficiently designed wireless sensor nodes may achieve operating timescales as long as years off a single battery.

Today’s typical wireless RF microcontroller system-on-chips targeted at Internet-of-Things applications typically consume about 1-5 microwatts in their “sleep” state, increasing to about 0.5-1.0 milliwatts with the microcontroller active, and up to about 50 milliwatts for brief periods during active radio transmission.

As an example of the active development in this field, the International Electrotechnical Commission has recently ratified the new ISO/IEC 14543-3-10 standard, specifying a Wireless-Short-Packet protocol optimised for ultra-low-power and energy-harvesting nodes in wireless sensor networks.

It is the first and only existing standard for wireless applications that is also optimised for energy harvesting solutions, aimed at energy-harvesting wireless sensors and wireless sensor networks with ultra-low power consumption.

For a small, low-power embedded device that receives a reasonable amount of sun each day, a moderately small solar panel is perfectly capable of supplying sufficient power, on average, to run a small, basic wireless network node consisting of a microcontroller, some sensors and an embedded low-power Wi-Fi, Bluetooth or 802.15.4/ZigBee radio transceiver.

In many applications, solar photovoltaic is the most familiar, relatively mature choice for low-power network nodes operating outdoors or under good indoor light conditions. However, other technologies suitable for harvesting small amounts of power from the ambient environment exist. For example, a wireless sensor node set up to monitor bearing wear in a generator could employ a piezoelectric crystal as a vibrational energy harvester, converting motor vibration into usable energy.

As an example of a controller IC one may use for the power supply in a small solar powered system, the Linear Technology LTC3105 is a high-efficiency step-up DC/DC converter that can operate from input voltages as low as 225 millivolts, with a built-in maximum power point controller (MPPC). As well as solar cells, this device is well suited to other low voltage, high impedance energy harvesting transducers such as thermoelectric generators.

For some systems it is also practical to use batteries alone – for example, lithium-ion, lithium-polymer or nickel metal-hydride batteries – and rely on user intervention to simply recharge and replace the batteries where needed.

Lithium-ion batteries provide good energy density and many convenient cycles of repeated charge and discharge, but these batteries require precise control to avoid over-discharge or over-charge conditions which can permanently damage the battery.

Despite their risk of fire and damage if mishandled, lithium-ion batteries provide very good discharge current capability, high energy density, and the ability to survive many repeated charge cycles embedded inside devices which are charged and used without their battery being replaced.

Libelium’s WaspMote platform is an open-source wireless sensor network platform specifically focussed on the implementation of low-power modes, allowing individual battery-powered nodes (or “motes”) to be completely autonomous and to run for many months or years without maintenance.

Depending on the duty cycle, types of sensors and the radio used, it is possible for a WaspMote node to run for as long as five years on a single battery, making WaspMote one good example of a hardware and software platform that is well suited to the use of solar power and other energy harvesting technologies in energy-efficient wireless sensor networks and Internet-of-Things applications.

We’ve only just scratched the surface of the options available to ensure your IoT nodes are powered effectively, and here at the LX Group we have the experience and expertise to solve your IoT power problems right through to a whole system to meet your needs.

Getting started is easy – join us for an obligation-free and confidential discussion about your ideas and how we can help bring them to life – click here to contact us, or telephone 1800 810 124.

LX is an award-winning electronics design company based in Sydney, Australia. LX services include full turnkey design, electronics, hardware, software and firmware design. LX specialises in embedded systems and wireless technologies design.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.

The new PSoC-4 BLE series of programmable system-on-chip devices from Cypress enables system designers to create low-power, sensor-based wirelessly-connected systems using integrated programmable analogue front ends, programmable digital peripherals – industry-leading CapSense touch sensor capability for user interfaces all integrated together with a Bluetooth 4.0 (Bluetooth Low Energy) radio and an ARM Cortex-M0 microcontroller in a compact and cost-effective single-chip solution.

This highly-integrated one-chip Bluetooth Low Energy platform enables you to easily design low-power, wirelessly-connected solutions that are particularly well suited to real-time, low-power Internet-of-Things applications.

Bluetooth Low Energy has several potential benefits over Wi-Fi in some wireless connectivity applications, including minimal connection latency and very good energy efficiency, allowing for “always-on” smart, connected devices that run off small batteries for many months or even more than a year while seamlessly being embedded into everyday physical objects and the environment around us.

This makes the platform ideal for IoT end-node applications despite offering data rate and throughput that is lower than in Wi-Fi-based solutions. By combining the Bluetooth Low Energy radio with a 32-bit ARM Cortex-M0 processor in a single chip and adding flexible general-purpose analogue and digital peripherals – the PSoC 4 BLE platform aims to provide the right combination of processing horsepower and low power consumption with flexible and precise interfaces for external peripherals such as ADCs and sensors.

You can interface your Bluetooth-connected system with multiple different sensors easily by integrating custom analogue front ends and programmable digital peripherals around the high-performance 48 MHz ARM Cortex-M0 processor core, with no need for any extra chips.

The PSoC 4 BLE platform includes the Bluetooth Low Energy Protocol Stack and Profiles in an intuitive and easy-to-use GUI-based configuration tool, simplifying the design of your BLE systems. The PSoC 4 BLE chipsets reduce the complexity of RF antenna-matching network design by including an integrated balun, which also helps reduce the component count and the PCB footprint of your system.

A PSoC 4 BLE development kit has been designed by Cypress to allow for maximum flexibility in your design whilst also being as easy to use as possible and offering compatibility with standard Arduino-compatible “shields” when used in conjunction with appropriate software.

This development kit is built around easy to use PSoC 4 BLE and PRoC (Programmable Radio-on-Chip) BLE development modules which are complete, self-contained systems that include the main chip with all its I/O pins exposed for development, a tuned PCB antenna on board, power circuitry and easy access to programming pins.

You can simply hook up some sensors, LEDs and a coin-cell battery and you’re ready to go with your complete single-chip Bluetooth LE-enabled wireless sensor network device with analogue and digital acquisition on board. You can even design reliable, sophisticated and sleek user interfaces with Cypress’ CapSense capacitive touch-sensing technology, delivering superior noise immunity, water tolerance and proximity sensing in touch-sensitive applications such as user control panels.

Furthermore, these modules are FCC certified, so they can be deployed in your commercial products without requiring the certification that you may require for a bespoke RF design to meet FCC Part 15 regulatory requirements. These Cypress PSoC 4 BLE modules also meet CE and Canadian RSS-210 radio certification standards, so they’re ready to go into these markets in your commercial designs.

The Bluetooth Low Energy Pioneer Kit from Cypress enables customers to evaluate and develop BLE projects using the Cypress PSoC 4 BLE and PRoC BLE devices. The low-cost BLE Pioneer Kit includes example projects for common BLE profiles and example smartphone apps for both iOS and Android with full source code provided, allowing you to get up and running in no time with the development of Bluetooth Low Energy solutions for IoT applications.

You can design complete, sensor-based BLE systems easily with Cypress PSoC Creator, taking advantage of its vast catalogue of pre-characterised and production ready PSoC firmware “components” which enable you to concurrently design hardware and firmware with easy drag-and-drop assembly of modular software. For example, the Bluetooth Low Energy 4.1 specification has been abstracted into the new Bluetooth Smart “component” in PSoC Creator.

The Cypress PSoC 4 BLE development kit includes a Bluetooth Low Energy USB dongle that pairs with the CySmart BLE master emulation tool from Cypress, converting your Windows PC into a powerful Bluetooth LE debugging environment.

The kit design and layout allows for customers to easily develop embedded solutions that require both mixed-signal analog and digital capabilities along with wireless Bluetooth LE connectivity and highly optimised power efficiency without sacrificing microcontroller performance.

The development kit supports system-level designs using the Cypress PSoC Creator development environment, which includes numerous example projects to enable you to get started creating Bluetooth Low Energy connected, mixed-signal analogue embedded designs such as wireless sensor networks and IoT product designs as easily and as quickly as possible.

If this platform is of interest to your organisation – and you need an experienced partner to progress with – join us for an obligation-free and confidential discussion about your ideas and how we can help bring them to life – click here to contact us, or telephone 1800 810 124.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.

The success or failure of new Internet-of-Things products is predicated on many factors, one of those being autonomy for portable devices – that is, how long the battery will last between charges. The less power your devices uses, the more attractive it will be to the end user and customer. And to help with this goal in mind, a new standard has emerged.

The International Electrotechnical Commission has recently ratified the new ISO/IEC 14543-3-10 standard, specifying a Wireless Short-Packet (WSP) protocol optimised for ultra-low-power and energy-harvesting nodes in wireless sensor networks.

Devices in low-power wireless sensor networks and Internet-of-Things applications that utilise energy harvesting technology can draw energy from their surroundings – for example from vibration, light or heat sources. Energy harvesting enables the use of electronic control and automation systems that work independently of an external power supply, without maintenance and without ongoing energy costs for the nodes in the sensor network.

In some environments where harvesting of small amounts of energy from ambient sources is practical, this technology offers energy savings and fast and easy installation, without the need for power cables for example, along with reductions in ongoing maintenance requirements for battery-powered devices.

International standardisation will accelerate the development and implementation of energy-optimised wireless sensors and wireless sensor networks, with the potential to also open up new markets and areas of application for wireless sensor and IoT solutions. In addition to the existing established markets for home and building automation and energy efficiency technology, further application sectors such as the “smart home”, “smart grid” and solutions in industry, logistics and transport are likely to continue to emerge into the future, with a strong foundation of interoperability, standardisation and openness provided by this novel but field-proven standard.

However, this new IEC standard specifies the architecture and lower layer protocols – the physical layer, data link and networking layer. The higher layers in the OSI network model are not specified in this standard and other standards, either open standards or vendor-specific proprietary protocols, will be used to implement the higher layers of the network.

EnOcean, which develops energy harvesting wireless technology, is a pioneer in this field, and the company has been producing and marketing maintenance-free wireless sensor solutions for use in building and industrial automation for more than ten years, with EnOcean-based products currently installed in over 250,000 buildings around the world.

EnOcean’s wireless technology is already a firmly established technology for smart buildings, energy efficiency and automation applications. The EnOcean Alliance, a cooperative industry alliance established by EnOcean, sees the ratification of this new IEC standard as one of the key prerequisites for expanding the already highly successful, fast-growing ecosystem of EnOcean-enabled products and RF communication modules from EnOcean and other vendors.

Members of the EnOcean Alliance have already introduced more than 1200 interoperable EnOcean-based products, all of which comply with the new standard. Developers and manufacturers can therefore benefit from the EnOcean Alliance’s extensive practical experience, huge product range and installed base of products deployed by customers in the field along with many years of user education and familiarisation.

The EnOcean Alliance draws up the specifications of standardised applications and device profiles based on the IEC standard, with these “EnOcean Equipment Profiles” ensuring the interoperability of products from different vendors. These standardised profiles are optimised for ultra-low energy consumption, making them a useful, tried and tested complement to the new IEC wireless sensor networking standard and allowing smart, energy-efficient automation solutions to easily be realised that are non-proprietary and industry-neutral.

EnOcean’s technology pushes wireless sensor network technology and energy efficiency to the limits, with EnOcean’s range of self-powered wireless switches, sensors, controls and other modules combining small-scale energy-harvesting power supplies with ultra-low-power electronics and reliable wireless communications.

This enables developers to create self-powered wireless sensor solutions that are valuable for efficiently managing building, smart energy management and industrial applications. Together with the EnOcean Equipment Profiles drawn up by the EnOcean Alliance, this international standard lays the foundation for fully interoperable, open, self-powered wireless technology with a level of industry-wide standardisation comparable to today’s widely accepted protocols such as Bluetooth and Wi-Fi.

EnOcean’s technology allows fast development and marketing of new wireless solutions in building services, industry and other sectors, and standardised sensor profiles provide for interoperability of the resulting products. Devices from different manufacturers can then communicate and cooperate with other devices on the network.

Interoperability of different end-products based on EnOcean technology is an important success factor for the establishment of self-powered IoT and WSN technology in the market, and this is the reason the EnOcean Alliance pursues standardisation of communication profiles, ensuring that sensors from one manufacturer can communicate with receiver gateways of another, for example.

Software provided by the EnOcean Alliance also allows modular and versatile, user-friendly integration of these systems into end-user applications. End users thus have the entire product portfolio enabled by EnOcean and EnOcean’s self-powered energy-harvesting wireless sensor network technology at their disposal.

This allows vendors to focus on their product branding, services, support and installation, along with providing Internet services, mobile apps and other software products whilst using existing hardware and core technology – along with developing and offering hardware products to support their own specialised market niche, going beyond the existing portfolio of EnOcean-enabled products if this is desired.

And as a leading developer of IoT-enabled products, our team at the LX Group is ready to work together as your design partner to help reduce the power consumption of your new or existing product with the EnOcean standard or other options we can introduce.

To get started, join us for an obligation-free and confidential discussion about your ideas and how we can help bring them to life – click here to contact us, or telephone 1800 810 124.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.

Contiki is a lightweight, multitasking operating system aimed primarily at memory-constrained embedded systems, wireless sensor networks, low-power networked embedded devices and the general “Internet of Things”. Contiki is resource efficient, highly portable, and it is free, open-source software.

Although Contiki is free software and its underlying source code is freely downloadable, some commercial companies such as ThingSquare provide professionally supported solutions for the deployment of Contiki-based Internet-of-Things applications and products in the commercial sector, just as is the case with the Linux ecosystem.

Designed to run on embedded hardware platforms that are severely constrained in terms of memory, processing power and communication bandwidth, Contiki still offers a multitasking kernel and a built-in TCP/IP stack, and a real-world Contiki deployment can be run on an 8-bit microcontroller, for example, with only about 10 kilobytes of RAM, 30 kilobytes of flash, a clock on the order of 10 MHz and a power budget on the order of 10 milliwatts.

Thanks to these low system requirements, Contiki has been or is being ported to many common microcontroller platforms – such as Atmel AVR, Microchip dsPIC and PIC32, TI’s MSP430 low-power microcontrollers, and ARM-based systems such as the TI CC2538.

Networking is easy with Contiki, as it provides three lightweight, memory efficient networking stacks – the uIP TCP/IP IPv4 stack, the uIPv6 stack, providing support for IPv6 networking, and the Rime stack, which is a set of custom lightweight networking protocols designed specifically for low-power wireless sensor networks.

The IPv6 stack also contains the RPL routing protocol for increased tolerance of packet loss in low-power IPv6 radio networks and the 6LoWPAN header compression and adaptation layer for IEEE 802.15.4 radio networks. Contiki is particularly well suited to use with microcontroller systems-on-chip incorporating an IEEE 802.15.4 radio transceiver on board, such as the Atmel ATmega128RFA1 family or the Texas Instruments CC2538.

Such hardware platforms, combined with Contiki, provide highly integrated, cost-efficient, power-efficient single-chip wireless sensor network or Internet-of-Things platforms with wireless IPv6 802.15.4/6LoWPAN networking support on board, allowing IPv6 internet connectivity to be routed right down to the wireless, power efficient end nodes of an Internet-of-Things network.

The Rime stack is an alternative network stack that is intended to be used in applications where the overhead of the IPv4 or IPv6 stacks is prohibitive. The Rime stack provides a set of communication primitives intended for very lightweight applications in low-power embedded wireless networks, which by default include single-hop unicast, multi-hop unicast, network flooding and address-free data collection.

These primitives can be used on their own or combined to form more complex protocols and mechanisms whilst still maintaining the most lightweight mechanism possible to perform the networking task required.

Contiki also provides a set of mechanisms for reducing the power consumption of the system on which it runs, including the ContikiMAC radio duty cycling protocol for improving power efficiency in radio-networked platforms, keeping the radio powered down or running in a low-power mode for as much time as possible while still being able to receive and relay network messages.

These mechanisms enable powerful Contiki-based solutions in severely power-constrained environments such as battery-operated wireless sensor network devices that are expected to operate unattended for long periods of time without battery maintenance or replacement.

To run efficiently on memory-constrained systems, the Contiki programming model is based on protothreads, which are thread-like memory-efficient programming abstractions that share features of both multi-threading and event-driven programming to attain a low memory overhead.

The kernel invokes the protothread of a process in response to an internal or external event. Examples of internal events are timers that fire or messages being posted from other processes, whilst examples of external events could include external interrupts that are triggered by external sensor inputs, or radio-triggered interrupts created by incoming packets on the wireless network.

These protothreads are cooperatively scheduled, meaning that a Contiki process must always explicitly yield control back to the kernel at regular intervals. Processes may use a special protothread construct to block waiting for events while yielding control to the kernel between each event invocation.

Contiki supports per-process optional pre-emptive multi-threading, interprocess communication using message passing through events and an optional GUI subsystem with either direct graphic support for locally connected terminals or networked virtual displays via VNC or Telnet. However, the use of a graphical user interface does increase memory requirements a little, from a minimum of 10 kilobytes of RAM up to a minimum of about 30 kilobytes of RAM.

The Contiki system includes a network simulator called Cooja. The Cooja Contiki Network Simulator simulates networks of nodes running Contiki which may belong to one of three classes – emulated nodes, where the entire hardware of each node is emulated, Cooja nodes, where the Contiki code for the node is compiled for and executed on the simulation host, or Java nodes, where the behaviour of the node must be reimplemented as a Java class.

A single Cooja simulation may contain many nodes from a mixture of any or all of the three classes. Emulated nodes can also be used to include non-Contiki nodes in a simulated network environment. Cooja can also be used to simulate real-world physical effects in large wireless mesh networks, such as packet loss and network degradation in RF networks.

With the combination of low-powered embedded wireless hardware, Contiki and the tools included – you have the foundation for a scalable, efficient and contemporary Internet-of-things.

To get started with your own ideas and Contiki, or to explore other options to solve your problems – join us for an obligation-free and confidential discussion about your ideas and how we can help bring them to life – click here to contact us, or telephone 1800 810 124.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.

Next in our series examining emerging low-power wireless standards, we consider 6LoWPAN, which stands for “IPv6 over Low-Power Wireless Personal Area Network”. This is a set of networking standards and specifications which is designed to address the ideas that the Internet Protocol (IPv6 in particular) can be and should be applied to even the smallest embedded wireless Internet-of-Things connected devices right out to the “end branches” of the network; and that power-efficient embedded devices with limited processing power should be fully able to be a part of the Internet of Things, including the use of IPv6 network connectivity.

Whilst the Internet Protocol is the workhorse for the Internet and local-area networks, the IEEE 802.15.4 standard defines the networking of wireless mesh devices. Although the two different protocols are inherently different, the 6LoWPAN specification defines encapsulation and header compression mechanisms that allow IPv6 packets to be sent and received over IEEE 802.15.4 wireless networks, essentially allowing the two standards to operate together, efficiently bringing the Internet to small, power-efficient, cheap devices without the relatively high cost, complexity and power consumption required to implement IEEE 802.11 wireless LAN connectivity at every wireless network node.

For example, a typical embedded 802.11 Wi-Fi module may consume 250 mA while it is awake and actively transmitting, and it may well require a separate microcontroller to interface it to the sensors or other electronics required for a particular application. On the other hand, a system-on-chip incorporating a microcontroller combined with an 802.15.4/6LoWPAN-compatible radio transceiver may only consume 25 mA when it is awake and actively transmitting RF data – an order of magnitude less power consumption.

6LoWPAN is well suited to small, compact, relatively low-cost embedded Internet-of-Things appliances that require wireless connectivity to the LAN and to the Internet but can accept connectivity at a relatively low data rate. Examples may include embedded automation, building control systems and wireless sensor networks in home, office and industrial environments, as well as smart energy metering, measurement and control networks. Devices such as smart meters may collate their data via a 802.15.4/6LoWPAN mesh network before sending the data back to the billing system over the IPv6 backbone.

Whilst IP networks are typically designed to optimise speed whilst managing traffic issues such as network congestion, 802.15.4 systems are designed to give a higher priority to efficient low-power operation and optimisation of memory use, maximising their utility on small, cheap, memory-constrained microcontrollers.

There are some complexities involved in interfacing the two systems elegantly – for example, whilst IPv6 requires a maximum transmission unit of at least 1280 bytes, the 802.15.4 physical layer allows a maximum of 127 bytes per packet, including the payload. The management of addresses for devices that communicate across both the dissimilar domains of IPv6 and IEEE 802.15.4 is also cumbersome, as is the routing of packets between the IPv6 domain and the PAN domain.

Since IP-enabled devices may require the formation of ad-hoc networks particularly during initial setup and configuration, the current state of neighbouring devices and the services hosted by such devices will need to be known. This requires a mechanism for device discovery of the neighbouring devices present in the network.

All 802.15.4 networks connected to the Internet, using 6LoWPAN or otherwise, do require the hardware and software of a physical “bridge” or “gateway” at some point or points in the network, in order to connect the 802.15.4 wireless mesh network to an 802.11 wireless LAN or wired Ethernet. Multiple such nodes mitigate the possibility of single-point failure of network connectivity for the mesh network, at the price of increased network complexity and hardware cost.

IPv6 nodes are assigned 128-bit IP addresses in a hierarchical manner, through an arbitrary length network prefix. IEEE 802.15.4 devices may use either 64-bit extended addresses or 16-bit addresses that are unique within a PAN (a Personal Area Network, which is a group of physically colocated 802.15.4 nodes) as long as an association between a node and a particular PAN has occurred. A particular PAN can also be identified by giving it a PAN ID, allowing the devices of that PAN to easily be recognised – for example, a particular PAN may be associated with a particular building or a particular room.

IEEE 802.15.4 is specifically intended for compact, cheap devices with a relatively low power consumption, operating efficiently from power sources such as batteries. After all, for networks of numerous Internet-of-Things appliances to become ubiquitous, individual wireless hardware nodes need to be as compact, unobtrusive and as cheap as possible.

Making each hardware device as small as possible also allows for portability and greater flexibility in how the devices are used – in wearable computing, for example. However, devices that don’t need to be wireless can be kept in the IP domain of the network and wired in to copper Ethernet – and if portability isn’t required, this means more bandwidth is available to the device. In such a case, a wired mains power supply may also be used, meaning that a larger amount of power is available.

In applications where wireless networking is required but device cost and power efficiency does not need to be so tightly constrained, or where more network bandwidth is required, 802.11 wireless networking may be chosen instead of 6LoWPAN over 802.15.4, keeping the device in the IP domain.

As you can imagine the 6LoWPAN standard offers new levels of compatibility with upcoming infrastructure and is perfect for low-power applications. And if this meets your needs but you’re not sure how to progress with a reliable implementation, we can partner with you to take care of this either in revisions of existing products or as part of new designs. With our experience in retail and commercial products we have the ability to target your product’s design to the required end-user market and all the steps required to make it happen.

We can create or tailor just about anything from a wireless temperature sensor to a complete Internet-enabled system for you – within your required time-frame and your budget. For more information or a confidential discussion about your ideas and how we can help bring them to life – click here to contact us, or telephone 1800 810 124.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.

The Bluetooth wireless data protocol has been in use for over ten years, and in recent time the new low energy standard has been introduced. This gives designers another option for wireless connectivity between devices with an extremely low power consumption. In the following we examine what it is, the benefits and implementation examples.

Bluetooth LE (for “low energy”) is aimed at novel applications of short-range wireless communication in connected Internet-of-Things devices for medical, fitness, sports, security and home entertainment applications, and was merged into the main Bluetooth specification as part of the Bluetooth Core Specification v4.0 in 2010.

Also known as “Bluetooth Smart”, it enables new applications of Bluetooth networking in small, power-efficient Internet-of-Things devices that can operate for months or even years on tiny coin cell batteries or other small-scale energy sources. Bluetooth LE devices offer ultra-low power consumption, particularly in idle or sleep modes, multi-vendor interoperability and low cost, whilst maintaining radio link range that is sufficiently long enough for the intended applications.

The Bluetooth LE protocol is not backwards-compatible with the “classic” Bluetooth – however, the Bluetooth 4.0 specification does allow for dual-mode Bluetooth implementations – where the device can communicate using both classic Bluetooth and Bluetooth LE. Whilst Bluetooth Low Energy uses a simpler modulation system than classic Bluetooth, it employs the same 2.4 GHz ISM band, allowing dual-mode devices to share a common antenna and RF electronics for both Classic and Bluetooth LE communication.

Small, power-efficient devices like wearable athletic and medical sensors are typically based on a single-mode Bluetooth LE system in order to minimise power consumption, size and cost. In devices like notebooks and smart phones, though, dual-mode Bluetooth is typically implemented, allowing communication with both Bluetooth LE and classic Bluetooth devices. When operated in Bluetooth LE mode, the Bluetooth LE stack is used whilst the RF hardware and antenna is usually the same set of hardware as used for classic Bluetooth operation.

Devices using Bluetooth LE typically have a power consumption, for Bluetooth communication, which is a fraction of that of classic Bluetooth devices. In many cases, devices can operate for a year or more on a single coin cell. This potentially makes Bluetooth LE very attractive for Internet-of-Things networks, telemetry and data logging from environmental sensor networks, for example.

Since many modern consumer devices such as mobile phones and notebooks have built-in Bluetooth LE support, data can be delivered directly to the user’s fingertips from the Bluetooth sensor network with no need for an intermediary gateway or router as would be required for an Internet-of-Things network employing other technologies such as 802.15.4 ZigBee. This direct interoperability with a large installed base of smart phones, tablets and notebooks could potentially be a very significant attraction of Bluetooth LE networks in wireless sensor network and Internet-of-Things applications.

An active Bluetooth radio has a peak current consumption on the order of about 10 milliamps, reduced to about 10 nanoamps (ideally) in sleep mode. In a Bluetooth LE system, the objective is to operate the radio with a very low duty cycle on the order of about 0.1-0.5%, resulting in average current consumption on the order of 10 microamps. At an average current consumption of 20 microamps, such a system could be operated off a typical CR2032 lithium coin cell (with a charge capacity of 230 milliamp-hours) for 1.3 years without battery replacement.

The lower power consumption of Bluetooth LE is not achieved by the nature of the radio transceiver itself (since the same RF hardware is typically used, in dual-mode Bluetooth devices), but by the design of the Bluetooth LE stack to allow low duty cycles for the radio and optimisation for transmission in small bursts – a Bluetooth LE device used for continuous data transfer would not have a lower power consumption than a classic Bluetooth device transmitting the same amount of data.

The Bluetooth specifications define many different profiles for Bluetooth LE devices – specifications for how a device works in particular families of applications. Manufacturers are expected to implement the appropriate profiles for their device in order to ensure compatibility between different devices from different vendors. A particular device may implement more than one profile – for example one device may contain both a heart rate monitor and a temperature sensor. Here is a non-exhaustive list of a few different Bluetooth LE profiles in use:

Health Thermometer Profile, for medical temperature measurement devices.
Glucose Monitor Profile, for medical blood glucose measurement and logging.
Proximity Profile, which allows one device to detect whether another device is within proximity, using RF signal strength to provide a rough range estimate. This is intended for security applications as an “electronic leash”, allowing the detection of devices being moved outside a controlled area.
Running Speed and Cadence profile, for monitoring and logging athletic performance.
Heart Rate Profile, for heart-rate measurement in medical and athletic applications.
Phone Alert Status Profile, which allows a client device to receive notifications (such as an incoming call or email message) from a smart phone. As an example, this is employed in the Pebble smart watch.

The Bluetooth LE shows a lot of promise, and with a minimal chip set cost gives the designer another cost-effective wireless protocol. And if this meets your needs but you’re not sure how to progress with a reliable implementation, we can partner with you to take care of this either in revisions of existing products or as part of new designs. With our experience in retail and commercial products we have the ability to target your product’s design to the required end-user market and all the steps required to make it happen.