iBeacon, Eddystone, Bluetooth, IoT sensor beacons, apps, platforms
Small beacons are sometimes needed so that they remain unobtrusive or need to be embedded into larger devices. The smallest, cased, beacons we supply are:
The compromise with small beacons is that they have CR2032 batteries that don’t last as long as larger battery beacons. If the beacons won’t be moving and you have access to USB power, consider using USB beacons that are also small.
Almost all beacons are slight derivations of a few standard circuit designs and firmware provided by Texas Instruments, Dialog and Nordic who produce the System On a Chip (SoC) inside beacons. The SoCs are general purpose devices that can do a lot more than just advertise as beacons but the beacon manufacturers only provide fixed firmware that performs just this one function, occasionally with additional sensing.
The use of firmware-based SoCs for beacons means there’s a lot of hardware and software (SDKs) that goes into creating a beacon. Much of this isn’t needed if the chip is designed for the single purpose of being a beacon. We previously mentioned the AK1594 but have yet to see any designs making use of this device.
The InPlay NanoBeacon IN100 is a newer device that has recently received Bluetooth 5.3 certification. It’s small (DFN8 is 2.5 x 2.5mm), inexpensive (designs using it are expected to be <$1) and no firmware or SDK is required.
The IN100 uses only 650nA when used with 1 minute advertising intervals that means it will last a very long time under battery power. The range can be up to several hundred meters. It’s configured using a programmer board connected by USB. A smartphone app is used for configuration. InPlay have a video demonstrating configuration:
We expect this SoC will end up being embedded in products rather than being used stand-alone in beacons because beacon manufacturers are already heavily invested into firmware-based beacons.
We often get asked if it’s possible to track smartphones using Bluetooth. For example, a retailer might want to know how long someone stays in their store and whether they visit again.
While iOS devices advertise Bluetooth continuity messages it’s not possible to track iOS devices using their Bluetooth MAC address because the address changes over time in order to defeat such tracking. However, as previously mentioned, Bluetooth MAC randomisation can be defeated. Android devices don’t usually advertise but some do if Covid tracking is on.
There’s a new paper by researchers at UC San Diego on Evaluating Physical-Layer BLE Location Tracking Attacks on Mobile Devices (PDF). It looks into Bluetooth physical-layer patterns to track a variety of device types.
A tool has been created to automate discovery of imperfections in signal modulation.
These imperfections are caused by manufacturing variations in the transmitter hardware.
Some, but not all, devices have unique fingerprints and can be tracked.
The MDPI has a special issue of Sensors Journal with a collection of papers related to Bluetooth LE.
BLE applications can be found in a wide range of domains, e.g., smart home, smart cities, smart health, smart agriculture, or Industry 4.0. BLE is enabling the interaction between humans and smart objects, as well as between smart objects themselves. BLE has also been leveraged for innovative location-based applications, opportunistic data collection and crowd-sensing.
All the papers are available free of charge under open access:
Detecting Proximity with Bluetooth Low Energy Beacons for Cultural Heritage
Optimizing the Bluetooth Low Energy Service Discovery Process
Empirical Study of a Room-Level Localization System Based on Bluetooth Low Energy Beacons
Obstruction-Aware Signal-Loss-Tolerant Indoor Positioning Using Bluetooth Low Energy
Efficient Communication Scheme for Bluetooth Low Energy in Large Scale Applications
Experimental Evaluation of 6BLEMesh: IPv6-Based BLE Mesh Networks
Energy Modeling of Neighbor Discovery in Bluetooth Low Energy Networks
Bluetooth 5.1: An Analysis of Direction Finding Capability for High-Precision Location Services
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 use of the SoC in the following Bluetooth solutions:
It’s mentioned that hospitals are struggling to manage IoT:
13 percent of hospitals have no inventory of their Internet-connected devices or any way of knowing how many connected medical devices are deployed in their facility… costing their facilities between $21.5k and $45.7k an hour
There’s also an article ‘Dog Gone’ showing wearables are rapidly being worn by animals as owners want to ensure their pets fitness, health and security.
The global pet technology market, which accounted for over $5.5 billion in 2020, is set to grow at 22 percent CAGR from 2021 to 2027 when it will be worth over $20 billion
There’s new research by the Institute of Information Science and Technologies, Pisa, Italy on Detecting Proximity with Bluetooth Low Energy Beacons for Cultural Heritage. The paper starts by describing alternative technologies including Ultra-wideband (UWB), Near Field Communication (NFC) and vision.
The RE.S.I.STO project allows media on the medieval town of Pisa to be accessible via smartphones and tablets. The system is implemented using the React Native Javascript Framework to allow cross-platform aps to be created on iOS and Android.
Beacons are attached to exhibits and the paper compares two proximity detection algorithms, a ‘Distance-based Proximity Technique’ and a ‘Threshold-based Proximity Technique’. The paper describes stress, stability and calibration testing of the system.
The researchers found a strong variation of RSSI value for different tags that they say is caused by the varying channel (frequency) used by Bluetooth LE as well as environmental issues such as obstacles, fading and signal reflections.
The system was able to successfully detect the correct artwork with an accuracy up 95% using the Distance-based Proximity Technique.
We previously mentioned how cost, battery life and second sourcing are the main advantages of Bluetooth over Ultra-Wideband (UWB). An additional, rarely mentioned, advantage is scalability.
Servers that process Bluetooth or Ultra-Wideband support a particular maximum throughout. The rate at which updates reach systems depends on the number of assets, how often they report and the area covered (number of gateways/locators). Each update needs to be processed and compared with very recent updates from other gateways/locators to determine an asset’s position.
For Bluetooth, updates tend to be of the order of 2 to 10 seconds but in some scenarios can be 30 seconds or more for stock checking where assets rarely move. Motion triggered beacons can be used to provide variable update periods depending on an asset’s movement patterns. This allows Bluetooth to support high 10s of thousands of assets without overloading the server.
For Ultra-Wideband, refresh rates tend to be of the order of hundreds of milliseconds (ms) thus stressing the system with more updates/sec. This is why most Ultra-Wideband systems support of the order of single digit thousands of assets and/or smaller areas. More frequent advertising is also the reason why the tags use a lot of battery power.
How does all this change with the new Bluetooth 5.1 direction finding standard? The standard was published in January 2019 but solutions have been slow to come to the market. The products that have so far appeared all have shortcomings that mean we can’t yet recommend them to our customers. Aside from this, in evaluating these products we are seeing compromises compared to traditional Bluetooth locating using received signal strength (RSSI).
Bluetooth 5.1 direction finding needs more complex hardware that, at least in current implementations, are reporting much more often. The server has to do complex processing to convert phase differences to angles and angles to positions thus supporting fewer updates/sec. Bluetooth direction finding is looking more like UWB in that cost, scalability and battery life are sacrificed for increased accuracy. Direction finding locators are currently x6 to x10 more costly than existing Bluetooth/WiFi gateways. Beacon battery life is reduced due to the more frequent and longer advertising. We are seeing Bluetooth 5.1 direction finding being somewhere between traditional Bluetooth RSSI-based locating and Ultra-Wideband in terms of flexibility vs accuracy.
Despite these intrinsic compromises, Bluetooth direction finding is set to provide strong competition to UWB for high accuracy applications. We are already seeing UWB providers seeking to diversify into Bluetooth to provide lower cost, longer battery life and greater scalability.
There’s a new paper from the journal Telkomnika Telecommunication, Computing, Electronics and Control on Smartphone indoor positioning based on enhanced BLE beacon multi-lateration (pdf). The paper by Ngoc-Son Duong of Vietnam National University describes a relatively simple method to improve location accuracy.
The paper starts by describing trilateration and the author voices the opinion that another method, fingerprinting, requires a lot of effort and isn’t feasible for practical implementation.
The new method makes use of the fact that accuracy is usually good when the received signal strength (RSSI) is -70 dBm or better. The use of more beacons and basing calculations on ‘reliable circles’ of higher signal strength, when available, provides for more accuracy.
The data is also filtered using a Kalman filter to reduce signal noise by about 37%.
Due to the pandemic, hospitals and care facilities have been experiencing greater patient numbers leading to pressures to accelerate digital transformation to increase efficiency. At BeaconZone, these are the main reasons customers have been using locating systems:
However, there are many more areas suitable for increasing efficiency and safety:
Time saved improving the above activities leads to more time being spent with patients and hence potentially saved lives.
Here are some considerations if you are comparing solutions:
One final tip. It’s our experience that healthcare providers under-estimate the human element in attempting to implement new systems. There are often internal problems as to who will be responsible for a) purchasing, b) installing and c) running new systems. Work these out and agree up-front before embarking on these transformative changes so as to prevent your project becoming blocked.
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Researchers from Japan have created a Bluetooth Low Energy Emulator for testing devices. Their paper, BluMoon: Bluetooth Low Energy Emulator for Software Testing BLE emulator called BluMoon for testing software systems using BLE (pdf), explains how it can be difficult to test how receiving Bluetooth devices’ behave when encountering other Bluetooth devices with varying signal level and interference.
The signal level and interference vary change depending on the position of the sender and receiver. They also vary depending on the surrounding environment. The signal level (RSS) is affected by reflection, shielding, and diffraction by surrounding objects, walls and the ground. Instead, testing requires known signal level and interference values.
The paper describes a software-implemented BLE controller, BluMoon, that calculates the received signal strength for each frame and imitates radio interference. The emulator replaces the controller with the HCI as the boundary.
BluMoon performs BLE communication emulation frame by frame and is implemented on Linux using the BlueZ Bluetooth stack.
