FEATURE WIRELESS TECHNOLOGY
IMPLEMENTING WIRELESS CONNECTIVITY
Nick Robins, Technical Director at Alpha Micro Components explores the basis for provisioning IoT connectivity and anticipating future product networking requirements for a fully integrated environment
T
he Internet of Things (IoT) is now starting to become more defined as
companies continue to embrace the concepts to deliver a host of new products and services. In the world of consumer applications, such as sports fitness monitors and home automation systems, the scope of the data provided and analysed tends to be rather disparate. However, in the industrial and commercial world, where the number of deployed sensors and controls are many more, an increasing number of business service providers are fully embracing the transformative effects of machine-to- machine (M2M) and the IoT. Needless to say, the IoT, by definition, requires reliable communication and in many cases the expectation is that communication is constantly available. In the industrial sector most edge devices such as sensors and control actuators use wireless communication for pure convenience. For consumer IoT applications the portability aspect typically dictates the device being battery powered too. From the wireless perspective, one of the first considerations will be the communications protocol that you are going to use. With a myriad of different standards available, the most popular ones being Bluetooth, Wi-Fi and ZigBee, there are a couple of selection criteria that need to be reviewed first. These include estimating the amount of data to be transferred, over what range communications is required and how frequently the data needs to be sent. As always in engineering there are trade-offs to be made and one of those might be the need to balance the attributes highlighted above with the available power budget. For regularly sending large volumes of data, Wi-Fi or Bluetooth Classic would be best. For smaller amounts of data, such as reading a temperature sensor and communicating over a short distance to a data aggregation gateway once every ten minutes Bluetooth low energy (BLE) would be the ideal candidate. Typically BLE can communicate up to
30 metres over line of sight but in practice this can be reduced significantly due to absorption by walls, partitions
16 SEPTEMBER 2015 | ELECTRONICS
example, consider an application gateway. This might be for use in a hospital drug dispensing application where Bluetooth connects multiple bar code scanners to the gateway, and data is then passed by Wi-Fi to a server or cloud-based application. By scanning both the drug(s) to be dispensed and the patient’s barcode the nurse can quickly validate that the prescription is in order and record the batch number of the items dispensed and the time at which they are given to the patient. An example of a multiradio module,
and ceilings in buildings. The emerging concepts of using mesh networks might then be a considered a solution.
WIRELESS CONNECTIVITY When embarking on the initial product design and deciding how to implement the wireless connectivity, engineers could decide to implement a discrete wireless design although the vast majority would choose to use a pre-certified wireless module. Incorporating a wireless module into a design saves a significant amount of development time, not only for the actual wireless design but time is saved that would otherwise be spent certifying the design for use in all the likely regions of the world where the product might be sold. Add to that the associated costs of employing specialist wireless engineers or contractors and hiring the appropriate wireless test and measurement equipment, you can see that a module- based approach to implementing wireless connectivity is a prudent one. As IoT applications continue to evolve there is an increasing need to combine multiple wireless protocols, such as Wi-Fi and Bluetooth into a design. In some instances new edge devices are being installed in industrial automation systems as replacement sensors or controls where the previous connectivity method was a serial cable. In order to fully utilise the capabilities of the new sensor a multi- radio module might be essential. For
illustrated in Figure 1, is the ODIN-W2 series from u-blox available from Alpha Micro. This compact standalone module provides a dual-mode Bluetooth v 4.0 transceiver that can operate in either Classic Bluetooth or Bluetooth Low Energy mode, and a dual-band (2.4 and 5GHz) Wi-Fi transceiver. Featuring the industry standard AT-
command instruction set and integrated embedded driver and stack, the module supports multiple concurrent Bluetooth and Wi-Fi connections that can operate in Wireless Multidrop or Extended Data Mode for advanced applications. Such a module provides much communication flexibility.
Figure 1 shows the ODIN-W2 series from u- blox available from Alpha Micro
MODULAR APPROACH Overall a multiradio module significantly decreases the amount of development effort required and the component count. The large degree of integration within the module also ensures that it is much smaller than its discrete equivalent thereby occupying a lot less board space, something that is crucial in today’s space- constrained designs. The u-blox module for example
measures just 14.8 x 22.3 x 4.5mm. Also, there will be fewer connections required to a module, typically that of power and data, which in the case of the ODIN-W2 module would normally be via a UART interface. IoT-based applications have always
promised to deliver disruptive and transformational influences to our homes and offices. Wireless communication is making sure that promise is fulfilled.
Alpha Micro
www.alphamicro.net 01256 851770
/ ELECTRONICS
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