Nordic Semiconductor, the manufacturer of the System on a Chip (SoC) in many beacons, has published the latest online issue of Wireless Quarter Magazine. It showcases the many uses of Nordic SoCs.
The latest issue of the magazine highlights the increasing use of IoT. Nordic Semiconductor has been known for enabling Bluetooth and cellular solutions and with their recent acquisition of Imagination Technologies this now extends to WiFi.
The magazine covers many usecases including:
Bluetooth connected prosthetics
CHIP smart home
There’s also an informative article exploring the usefulness of patents.
You can find the processor chip in the specification section of our beacon descriptions. Most people don’t know what this means or implies. This article will help you make a more informed choice.
There are currently three main chip families from Texas Instruments (CC25xx, CC26xx), Dialog Semiconductor (DAxxxx) and Nordic Semiconductor (nRF51xxx and nRF52xxx). These chip manufacturers publish standard electronic circuits and software SDKs that beacon OEMs use for their beacons. Hence, most beacons, within a chip family, have very similar designs. Small differences in implementation of board layout in areas such as the power supply, grounding, terminations, connectors and the antenna can cause electrical differences that can cause loss of power.
The strength of the beacon radio signal is affected more by the quality of the beacon implementation, particularly the antenna, rather than the choice of chip. This is also evident in real world tests. We have performed RSSI strength and stability tests on the beacons we sell and haven’t yet found any correlation between signal strength and chip family.
The choice of SoC affects battery use. Newer chip families such as the Nordic nRF52 (as opposed to nRF51) and Texas Instruments CC2640 (as opposed to CC2541) are more power efficient.
Most beacon SoCs transmit up to +4dBm output power for a longer range. A few such as the nRF52840 and CC2640RF can be set to higher output power of +8dBm and +5dBM respectively, with a consequent reduction of battery life. If you are looking for longer range, it’s more usual to use a long range beacon with an additional output amplifier chip.
Beacons don’t generally need to store data because they are just sending out their unique id. However, sensor beacons do sense values over time that you might want to collect later via, for example, an app coming close to the beacon. Specialist devices such as social distancing beacons need to store close contacts for later collection.
Beacons use a System on a Chip (SoC), such as the Nordic nRF51, that includes memory. Most of the memory is used for the internal functioning of the beacon. Newer versions of SoC, for example the Nordic nRF52, have more memory that allows data to be stored.
There are some sensor logger beacons that store sensor values but this tends to be restricted to temperature logging.
Here at BeaconZone we create solutions based on products that use Bluetooth LE. The Bluetooth standards are created and maintained by the Bluetooth SIG. This post briefly explores the advantages and disadvantages of such standards and the opportunities and risks of going off-piste using 3rd party wireless standards.
The main advantage of the Bluetooth LE standard is interoperability. We can use beacons, sensor beacons, smartphones, gateways, single board computers such as the Raspberry Pi, laptops and desktops in solutions and be sure they can communicate using Bluetooth LE. More specifically, we can use the Bluetooth APIs on these platforms and they speak a common language and ‘just work’. Bluetooth has also recently introduced standards on top of the Bluetooth LE standard that provide for mesh networking and angle based location.
The Bluetooth LE standard has caused the ecosystem of System on a Chip (SoC) vendors such as Texas Instruments, Nordic Semiconductor and Dialog Semiconductor to create inexpensive sub-systems and SDKs that simplify implementing new products based on the standards. This, in turn, has created a large variety of devices that can talk to each other even though they use hardware from different vendors. The variety of devices has increased competition, keeping device prices down.
The problem with standards is that they evolve very slowly and might not be optimal for specific situations. This creates an opportunity for 3rd parties to create alternative wireless solutions such as Ultra Wideband (UWB) devices, custom mesh networking and custom location schemes that can provide better performance in aspects such as accuracy, physical range and battery life. These custom products cost more because they are more involved to create/manufacture and their unique features can command a higher price. However, there’s the risk that if/when the companies producing these products go out of business, your solution will become end-of-life with no second sourcing. This is a particular risk when the product involves some sort of software as a service (SAAS), irrespective of standards.
Choosing a wireless technology for your solution involves a trade off between performance, cost and risk. It’s wise to first seek a standards-based and stand-alone (not SAAS) approach and only deviate if you find what you need to do isn’t served by available solutions.
Today’s Bluetooth devices use advertising, GATT connection and mesh. Advertising occurs over three channels to reduce the affects of wireless interference. When more than one device advertises at the same time, the data is lost. However, advertising takes of the order of 1ms so the chance of collision is usually small.
In contrast, BlueFlood uses concurrent transmissions (CT) that purposely synchronise transmissions such that if colliding packets are tightly synchronised and have the same contents, the resulting signal might be distorted, but highly probable that they do not destruct each other. This is used with the Glossy flooding protocol and 40 rather than 3 advertising channels.
CT-based protocols achieve enormous performance gains in terms of end-to-end reliability, latency and energy consumption even under harsh interference conditions
Concurrent transmissions are challenging using Bluetooth because transmissions need to be synchronised down to 250ns. Nevertheless, the researchers show this is possible using standard Bluetooth PHY and commercial Nordic SoCs. They achieved an end-to-end loss rate below 1% and managed to receive the signals on a standard smartphone. While the mechanism was fragile it was found to be viable.
New vulnerabilities, called SweynTooth, have recently been found in Bluetooth LE. The problems aren’t in Bluetooth itself but in software development kits (SDKs) provided by some System on a Chip (SoC) manufacturers.
There are three types of problem that can be triggered by sending particular data to Bluetooth devices: crash, deadlock and security bypass. Only some manufacturer’s SDKs are affected and only some of their SoCs models.
Texas Instruments, NXP, Cypress, Dialog Semiconductors, Microchip, STMicroelectronics and Telink Semiconductor SDKs are affected. The main manufacturer used in beacons in beacons and gateways is Nordic so the majority of beacons are not affected. Nevertheless, there are a few beacon models that use Texas Instruments and Dialog Semiconductors SoCs. Of these, very few use the specific affected SoC models.
The only affected devices we stock are the ABKey01, TON9128, TON9118, TON9108 that use the Dialog DA14580 SoC. You should avoid using these in critical scenarios because they can be caused to crash or deadlock. No beacons are vulnerable to the security bypass vulnerability.
As with all security issues, you have to put the possible attacks into perspective. The vulnerabilities are difficult to exploit in practice and it’s usually much easier to steal a beacon or remove its battery to make it inoperable.
The vulnerabilities are of more concern for critical medical devices such as pacemakers and blood glucose monitors.
Many people come to us asking for “programmable beacons” when in fact they want beacons with configurable iBeacon UUID, major and minor. All beacons allow the UUID, major and minor to be changed, usually via an iOS and/or Android app and sometimes via USB/UART for changing the values, over time, via a program.
Truly programmable beacons are those where the internal software can be updated. The beacon contains a system on a chip that’s small computer running code to implement the beacon functionality. In most cases, the software can be updated via pins on the PCB:
Programming requires use of a programmer:
It can be fiddly to program larger numbers so you use a custom-made jig:
It’s not possible to see and update the existing code in a beacon. Any newly uploaded program has to be created from scratch. This is called emdedded programming, is non-trivial and takes of the order of months. Our SensorMesh™ was created this way.