Readily available, first-rate wireless links are essential for building and running safe UAV systems. David Weight, principal electronics engineer at Waittcircuit, recently shared his thoughts on the importance developing and maintaining high-quality wireless links as the UAV industry expands.
One of the major challenges that is emerging in the UAV industry is maintaining wireless links with high availability. As UAVs start to share airspace with other vehicles, we need to demonstrate that a control link can be maintained in a wide variety of environments, including interference and non-line of sight. We are starting to see software defined radio used to build radios which are frequency agile and capable of using multiple modulation techniques. For example, being able to use direct links in open spaces where these are most effective, but being able to change to 4G type signals when entering more built-up areas as these areas can pose issues for direct links, but have good coverage for existing commercial telecoms. Being able to change the frequency and modulation also means that, where interference or poor signal paths are found, frequencies can be changed to avoid interference, or in extreme cases, be reduced to lower bands which allow control links to be maintained. This may mean that not all the data can be transmitted back, but it will keep the link alive and continue to transmit sufficient information to allow the pilot to control the UAV safely. — David Weight (Principal Electronics Engineer, Wattcircuit, UK)
Wireless IoT devices are becoming increasingly common in both private and public spaces. Phil Vreugdenhil, an instructor at Camosun College in Canada, recently shared his thoughts on the future of ‘Net-connected wireless technology and the ways users will interact with it.
I see brain-controlled software and hardware seamlessly interacting with wireless IoT devices. I also foresee people interacting with their enhanced realities through fully integrated NEMS (nano-electromechancical systems) which also communicate directly with the brain, bypassing the usual pathways (eyes, ears, nose, touch, taste) much like cochlear implants and bionic eyes. I see wireless health-monitoring systems and AI doctors drastically improving efficiency in the medical system. But, I also see the safety and security pitfalls within these future systems. The potential for hacking somebody’s personal systems and altering or deleting the data they depend upon for survival makes the future of wireless technology seem scarier than it will probably be. — Phil Vreugdenhil (Instructor, Camosun College, Canada)
NXP Semiconductors recently added the OL2385 family sub-GHz wireless transceivers to its low-power microcontroller and 2.4 GHz portfolio for Internet of Things (IoT) applications. Based on a PIN-to-PIN compatible, sub-GHz transceiver hardware platform, the OL2385 supports multiple wireless protocols (e.g., Sigfox, W-MBus powered by Xemex, and ZigBee IEEE 802.15.4).
With a two-way RF channel and common modulation schemes for networking applicatios, the OL2385 transceivers cover a wide range of frequency bands from 160 to 960 MHz. In addition, extended range radio operation is enabled with high sensitivity up to –128 dBm. Operation in congested environments is enhanced with 60 dB at 1 MHz of blocking performance and 60 dB of image rejection.
Platform features include: 14-dBm Tx output power compliant with ETSI limits; typical 29-mA transmit power consumption at full output power; less than 11 mA receive power consumption; excellent phase noise of –127 dBc at 1 MHz in the 868- and 915-MHz band for flexibility with external power amplifiers; and Japanese ARIB T108 standard compliant.
The OL2385 platform samples and development boards with SIGFOX are currently available. Mass production of preprogrammed parts are scheduled for the end of Q4 2017.
Dialog Semicondcutor recently announced it will be the exclusive supplier of Energous Corp.’s WattUp RF-based wireless charging ICs. As part of the partnership, Dialog will make a $10 million investment in Energous and work to help drive broader adoption of wireless charging in products such as smartphones, IoT devices, wearables, and more.
The partnership combines Energous’s uncoupled wireless charging technology and Dialog’s power-saving technologies. WattUp technology uses Dialog’s SmartBond Bluetooth low energy solution as the out-of-band communications channel between the wireless transmitter and receiver. Dialog’s power management technology then distributes power from the WattUp receiver IC to the rest of the device. Dialog’s AC/DC Rapid Charge power conversion technology delivers power to the wireless transmitter.
Interested in developing cloud-connected wireless sensing products? Silicon Labs recently introduced its Thunderboard Sense Kit for developing cloud-connected devices with multiple sensing and connectivity options. The “inspiration kit” provides you with all the hardware and software needed to develop battery-powered wireless sensor nodes for the IoT.
The Thunderboard Sense Kit’s features and benefits:
Silicon Labs EFR32 Mighty Gecko multiprotocol wireless SoC with a 2.4-GHz chip antenna
ARM Cortex-M4 processor-based
Supports Bluetooth low energy, ZigBee, Thread, and proprietary protocols
Silicon Labs EFM8 Sleepy Bee microcontroller enabling fine-grained power control
Silicon Labs Si7021 relative humidity and temperature sensor
Silicon Labs Si1133 UV index and ambient light sensor
Bosch Sensortec BMP280 barometric pressure sensor
Cambridge CCS811 indoor air quality gas sensor
InvenSense ICM-20648 six-axis inertial sensor
Knowles SPV1840 MEMS microphone
Four high-brightness RGB LEDs
On-board SEGGER J-Link debugger for easy programming and debugging
USB Micro-B connector with virtual COM port and debug access
Mini Simplicity connector to access energy profiling and wireless network debugging
20 breakout pins to connect to external breadboard hardware
CR2032 coin cell battery connector and external battery connector
Silicon Labs’s Simplicity Studio tools support the Thunderboard Sense
The Thunderboard Sense kit (SLTB001A) costs $36. All hardware schematics, open-source design files, mobile apps, and cloud software are included for free.
NFCRing’s new EMVCo-compliant, wearable payment ring features a Infineon Technologies contactless security chip. Operating like a contactless payment card, the ring enables users to pay for products via an EMVCo contactless-enabled payment terminal. The EMVCo’s member organizations include American Express, Discover, JCB, MasterCard, UnionPay, and Visa.
The Infineon SLE 77CLFX2407P contactless security cryptocontroller chip enabled the ring’s designers to develop a wearable that doesn’t have a battery. The chip acquires the energy it needs from the electromagnetic field.
National Instruments (NI) recently announced an early access version of the WLAN Measurement Suite with support for the IEEE 802.11ax (draft 0.1) high-efficiency wireless draft standard. Combined with NI’s RF vector signal transceiver (VST), the WLAN Measurement Suite enables you to measure the performance of their 802.11ax designs confidently in the presence of significant new changes to the 802.11 physical layer specification.
Aso called High-Efficiency Wireless (HEW), the 802.11ax is intended to improve the average throughput per user by a factor of at least 4× in dense user environments. This new standard focuses on implementing mechanisms to serve more users a consistent and reliable stream of data (average throughput) in the presence of many other users.
The WLAN Measurement Suite offers the power and flexibility to generate and analyze a wide range of 802.11 waveforms, such as 802.11a/b/g/n/j/p/ac/ah/af. Now, with the measurement suite’s latest update targeting 802.11ax, you can speed up development work on 802.11ax devices. The software supports key features of 802.11ax, including narrower subcarrier spacing, 1024-QAM, and multi-user orthogonal frequency division multiple access (OFDMA). The updated measurement suite also includes LabVIEW system design software example code to help engineers automate WLAN measurements quickly and easily.
NI’s platform-based approach helps ensure you can update their existing PXI RF test systems to support 802.11ax device testing with a simple software update and continue to do so as the 802.11ax standardization process evolves. You can take advantage of this smarter approach to RF test to help lower the cost of testing and better prepare for future connectivity and cellular standardization initiatives, such as 5G.
Oscium recently announced the WiPry 5x, a dual-band spectrum analyzer solution that visualizes all spectral activity on 2.4 and 5 GHz on both iOS and Android devices. A hardware plug-in accessory, the WiPry 5x makes possible to identify and avoid interferences and optimize wireless connectivity from a smartphone or tablet. The portable WiPry 5x is an excellent tool for field technicians, wireless professionals, and home audio enthusiasts who need to set up wireless audio networks.
Oscium currently offers the LogiScope (logic analyzer), iMSO-204L and iMSO-104 (mixed-signal oscilloscopes), WiPry-Pro Combo (combination spectrum analyzer and dynamic power meter), WiPry-Pro (2.4-GHz spectrum analyzer), and now the new WiPry 5x Dual Band Spectrum Analyzer (2.4 and 5 GHz) with cross platform support. By adding coverage to the Android market and supporting 5 GHz, Oscium has expanded its customer base and made some significant improvements in direct response to market’s demands.
The WiPry 5x visualizes all wireless activity on both the 2.4 and 5 GHz hands. Measurement settings include 802.11b, 802.11g, 802.11n, 802.11ac, and 802.15.4 (ZigBee). Also available is SSID-specific activity, which is ideal for troubleshooting home security, home automation, and home audio wireless installations.
The WiPry 5x costs approximately $499. WiPry software is free both in the Apple App Store and on Google Play. Although initial support will only include iOS version 7.0 or higher and Android version 4.0.3 and higher, the hardware can support other platforms such as Windows, Mac, and Linux. Compatible devices include Apple’s iPod touch (5th generation), iPhone 5 to 6S Plus models, and all iPads from the third generation forward, including the iPad Pro. All Android devices with USB On-The-Go are compatible.
Advances in wireless technologies are driving innovation in virtually every industry, from automobiles to consumer electronics. We recently asked 10 engineers to prognosticate on the future of wireless technology. Eileen Liu, a software engineer at Lockheed Martin, writes:
Wireless technology has become increasingly prevalent in our daily lives. It has become commonplace to look up information on smartphones via invisible networks and to connect to peripheral devices using Bluetooth connections. So what should we expect to see next in the world of wireless technology? One of the major things to keep an eye on is the effort for a global Internet network. Facebook and Google are potentially collaborating, working on drones and high-altitude helium balloons with router-like payloads. These solar-powered payloads make a radio link to a telecommunications network on Earth’s surface and broadcast Internet coverage downwards. Elon Musk and Greg Wyler are both working on a different approach, using flotillas of low-orbiting satellites. With such efforts, high-speed Internet access could become possible for the most remote locations on Earth, bringing access to the 60% of the world’s population that currently do not have access. Another technology to look out for is wireless power transfer. This technology allows multiple devices to charge simultaneously without a tether and without a dependency on directionality. Recent developments have mostly been in the realm of mobile phones and laptops, but this could expand to other electronic devices and automobiles that depend on batteries. A third technology to look out for is car-to-car communications. Several companies have been developing autonomous cars, using sensor systems to detect road conditions and surrounding vehicles. These sensors have shown promise, but have limited range and field-of-view and can easily be obstructed. Car-to-car communications allow vehicles to broadcast position, speed, steering-wheel position, and other data to surrounding vehicles with a range of several hundred meters. By networking cars together wirelessly, we could be one step closer to safe autonomous driving. — Eileen Liu, United States (Software Engineer, Lockheed Martin)
Each day, wireless technology becomes more pervasive as new electronics systems hit the market and connect to the Internet. We recently asked 10 engineers to prognosticate on the future of wireless technology. Penn State Professor Chris Coulston writes:
With the Internet of Things still the big thing, we should expect exciting developments in embedded wireless in 2016 and beyond. Incremental advances in speed and power consumption will allow manufactures to brag about having the latest and greatest chip. However, all this potential is lost unless you can deploy it easily. The Futurelec FT-232 serial-to-USB bridge is a success because it trades off some of the functionality of a complex protocol for a more familiar, less burdensome, protocol. The demand for simplified protocols should drive manufacturers to develop solutions making complex protocols more accessible. Cutting the cord means different things to different people. While Bluetooth Low Energy (BLE) has allowed a wide swath of gadgets to go wireless, these devices still require the presence of some intermediary (like a smart phone) to manage data transfer to the cloud. Expect to see the development of intermediate technologies enabling BLE to “cut the cord” to smart phones. Security of wireless communication will continue to be an important element of any conversation involving new wireless technology. Fortunately, the theoretical tools need to secure communication are well understood. Expect to see these tools trickle down as standard subsystems in embedded processors. The automotive industry is set to transform itself with self-driving cars. This revolution in transportation must be accompanied by wireless technologies allowing our cars to talk to our devices, each other and perhaps the roadways. This is an area that is ripe for some surprising and exciting developments enabling developers to innovate in this new domain. We live in interesting times with embedded systems playing a large role in consumer and industrial systems. With better and more accessible technology in your grasp, I hope that you have great and innovative 2016! — Chris Coulston, United States (Associate Professor, Electrical & Computer Engineering, Penn State Erie)
Wireless communications have revolutionized virtually every industry, from healthcare to defense to consumer electronics. We recently asked 10 engineers to prognosticate on the future of wireless technology. France-based engineer Robert Lacoste writes:
I don’t know if the forecasts about the Internet of Things (IoT) are realistic (some analysts predict from 20 to 100 billion devices in the next five years), but I’m sure it will be a huge market. And 99% of IoT products are and will be wireless. Currently, the vast majority of “things” connect to the Internet through a user’s smartphone, used as a gateway typically through a Bluetooth Smart link. Other devices (e.g., home control or smart metering) require the installation of a dedicated fixed RF-to-Internet gateway, using ZigBee, 6lowPan, or something similar. But the next big thing will be the availability of “connect anywhere” solutions, through low-power wide area networks, nicknamed LPWA. Even if the underlying technology is not actually new (i.e., using very low bit rates to achieve long range at low powers), the contenders are numerous: LORA Alliance, INGENU, SIGFOX, WEIGHTLESS, and a couple of others. At the same time, the traditional telcos are developing very similar solutions using cellular bands and variants of the 3GPP protocols. EC-GSM, LTE-MTC, and NB-IOT are the most discussed alternatives. So, the first big question is this: Which one (or ones, as a one-size-fits-all solution is unlikely) will be the winner? The second big question has to do with whether or not IoT products will be useful for society. But that’s another story! — Robert Lacoste, France (Founder, Alciom; Columnist, Circuit Cellar)
Linx Technologies recently introduced new pre-certified remote control and sensor transceiver modules. Built on the Hummingbird platform, the HumRC Series transceiver is a frequency hopping spread spectrum (FHSS) transceiver designed for reliable bidirectional remote control and sensor applications. Available in 900 MHz, the HumRC outputs up to 10 dBm, which results in a line-of-sight range of up to 1 mile.
The HumRC Series module is a completely integrated RF transceiver and processor designed for bidirectional remote control. It employs a fast-locking FHSS system for noise immunity and higher transmitter output power as allowed by government regulations.
The remote control transceiver has eight status lines that can be individually configured as inputs to register button presses or as outputs to drive application circuitry. A selectable acknowledgement indicates that the transmission was successfully received. Primary settings are hardware-selectable, which eliminates the need for an external microcontroller or other digital interface.
The transceiver also has two analog-to-digital (ADC) inputs for sensors or circuits that output an analog voltage. The module can automatically respond to a command with these values, so a sensor node does not need an additional microprocessor.
To aid rapid development, the HumRC Series low-cost RF modules are available as part of a newly conceived type of Master Development System. This development kit is intended to assist in the rapid evaluation and integration of the HumRC Series data transceiver modules. It features several preassembled evaluation boards that include everything needed to quickly test the operation of the transceiver modules.
Some people like to remotely start their cars when it’s cold outside. Dan Beadle took this idea one step further by Internet-enabling his mountainside retreat’s hydronics system. The innovative design enables him to warm the house well in advance of his arrival.
Serving up the current temperature involves several computers, a Wi-Fi access point, and a DPAC Airborne module.
In “Wireless Water Heater” (Circuit Cellar 163), Beadle writes:
My mountain home, where I have vacationed for years, is well insulated, making it a snap for the heater system to keep warm. I have a small, efficient heater; however, it takes forever to warm the house from a 50°F standby to a livable 68°F. Typically, I arrive late and shiver in my jacket for three or four hours until the house warms up—and that does not warm the entire house, just the portion needed to get through the night.
I had been thinking for a while about Internet-enabling the system. The idea was to turn on the heater before we start up the mountain. I have DSL at the house with a fixed IP. So, it seemed like it would be a simple task to enable a thermostat. I considered using an X10 thermostat, but, after a few of our X10-enabled lights found a mind of their own, I decided that I wanted better reliability. My next thought was to use simple copper to do the hook-up. I started planning a cable from my office/DSL entry up to the logical thermostat location. Then I procrastinated. I could not bring myself to run the wires along the surface of my redwood paneling. (And it was not at all feasible to remove the paneling.) Wireless makes the problem a lot simpler: there are no wires to run, and the applications processor and digital I/O on the module make the hardware design trivial.
In 1994, Circuit Cellar’s founder, Steve Ciarcia, asked: “What good is having ultimate control over your virtual audio/video environment if you have to get out of your chair to change the setup?” Great question. His answer was even better: “Outfit your home theater in style by adding an RF interface to the AVMux.”
In Circuit Cellar 46, Steve writes:
Using a couple of new chips from Maxim and Analog Devices, the AVMux facilitates effortless switching of up to eight video channels and up to eight sets of stereo audio channel pairs. Using the AVMux, I can effortlessly attach and reconfigure the connections between multiple VCRs, CD players, a Pro Logic decoder, a laserdisc player, and various other audio/video sources to the same set of amplifiers or in any number of different electronic combinations.
With the possible exception of the actual wiring chore itself, the basic multiplexer and control unit is quite straightforward and easily constructed. Unfortunately, solving the basic switching problems only served to create further design necessities. Let me explain.
The primary problem with commercial multiplexers (when they used to be available) is that they are housed in a box much like traditional stereo equipment with all the input/output jacks on the back. Such shortsightedness on their part also requires taking a chainsaw to your expensive CWD oak stereo cabinets to widen the minuscule wire access holes to actually route all these wires.
In 2001, while working on self-contained robot system called “Scout,” Tom Dahlin and Donald Krantz developed an interesting wireless data link. A tubular, wheeled robot, Scout’s wireless data link is divided into separate boards, one for radio control and another containing RF hardware.
Dahlin and Krantz write:
This article will describe the hardware and software design and implementation of a low-power, wireless RF data link. We will discuss a robotic application in which the RF link facilitates the command and control functions of a tele-operated miniature robot. The RF Monolithics (RFM) TR-3000 chip is the core of the transceiver design. We use a straightforward interface to a PIC controller, so you should be able to use or adapt much of this application for your needs…
Photo 1: The robot measures a little over 4″. Designed for teleoperated remote surveillance, it contains a video camera and transmitter. Scout can hop over obstacles by hoisting its tail spring (shown extended) and quickly releasing it to slap the ground and propel the robot into the air.
The robot, called Scout, is packed in a 38-mm diameter tube with coaxial-mounted wheels at each end, approximately 110-mm long. The robot is shown in Photo 1. (For additional information, see the “Key Specifications for Scout Robot” sidebar.) Scout carries a miniature video camera and video transmitter, allowing you to tele-operate the robot by sending it steering commands while watching video images sent back from Scout. The video transmitter and data transceiver contained on the robot are separate devices, operating at 915 and 433MHz, respectively. Also contained on Scout are dual-axis magnetometers (for compass functions) and dual-axis accelerometers (for tilt/inclination measurement).
Figure 1: For the radio processor board, a PIC16F877 provides the horsepower to perform transceiver control, Manchester encoding, and packet formatting.
Scout’s hardware and software were designed to be modular. The wireless data link is physically partitioned onto two separate boards, one containing a PIC processor for radio control, message formatting, and data encoding (see Figure 1). The other board contains the RF hardware, consisting of the RFM TR3000 chip and supporting discrete components. By separating the two boards, we were able to keep the digital noise and trash away from the radio.