Beacons Help Find Lost Dementia Patients

The Jockey Club Centre for Positing Ageing in Hong Kong has been working with The Hong Kong University of Science and Technology and St James Settlement to create a system to aid the search for older people with dementia who get lost.

The solution works on the premise that people who get lost generally go to places where there are other people. A Bluetooth beacon-based device is detected by an app installed by 23,400 ‘dementia angels’. They receive an alert when someone is lost and are asked to turn on Bluetooth and location. When the lost person is detected the location is anonymously sent to a cloud server and then to the caregiver to aid with searching.

The beacon comes in several forms including suitable for putting into a wallet or attached to a walking stick. In 45 out of 131 lost episodes, the caregivers were able to use the technology to help search for their relatives with dementia.

87% of caregivers thought that the iBeacon was easy to carry for the people with dementia and 82% observed that their relatives with dementia were willing to carry the iBeacon. 79% of caregivers were satisfied with the durability of the iBeacon and 75% thought that the designated mobile app was easy to use. In addition, 74% of caregivers trusted data security. The overall programme satisfaction rate was 85%, revealing that they held a positive view of using this technology in their daily lives to prevent getting lost.

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Beacons Past, Present and Future

Bluetooth beacons have evolved considerably over the last twelve years. Occasionally, we see Twitter comments such as ‘Remember iBeacon’ or ‘Beacons are dead’. Beacons aren’t dead. They are used in many situations and have, in some cases, evolved such that you don’t even know they are being used.

Bluetooth 4.0 devices started with the Bluetooth 4.0 specification in December 2010. The iPhone 4S and many Android devices were the first iOS device to use this new wireless protocol. Interoperability with smartphones is one the main reasons Bluetooth LE and beacons have become so popular.

While there were a few early, custom, Bluetooth LE devices that just advertised, the popularity of beacons was boosted by the announcement of the iBeacon protocol at the Apple Worldwide Developers Conference in 2013.

The First iBeacons

The iBeacon protocol actually didn’t add that much because it just used the standard Bluetooth 4.0 protocol with the data being interpreted in a particular way to uniquely identify the beacon. The important part was that iPhones would have CoreLocation APIs to detect these kinds of Bluetooth 4.0 devices.

Apple’s example usecases were mainly marketing, retail and consumer driven and this led to lots of startups creating new iBeacon platforms often with re-badged iBeacons with locked-in Software as a Service.

Google didn’t want to loose out but and their ambitions were wider in that they wanted to create what they called a Physical Web where smartphones could find and control devices using Bluetooth. The Eddystone profile was released by Google in July 2015 which, again, was a thin layer on top of the standard Bluetooth 4.0 protocol. Again, the important part was the software, provided by Google, that allowed Eddystone to trigger events in the Android Chrome and Android itself via the Play Services component.

A key part of Eddystone was Eddystone-URL that allowed the advertising of a shortened web address. However, the triggering mechanism was totally controlled by a Google server that had it’s own opaque rules and was frustrating because it didn’t always work.

Many more startups adapted their software and hardware designs to use Eddystone-URL. However, the spammy side of the marketing community took hold and by 25 October 2018, Google discontinued support for Android Bluetooth Nearby Notifications. This caused the end of a large number of startups based on beacon marketing.

During the ‘Eddystone age’ of 2015-2018 something longer lasting was happening. Some manufacturers adapted their beacons to become sensors for things like movement, temperature, humidity, air pressure, light, on/off, proximity, fall detection, smoke, natural gas and water leak. At the same time, manufacturers created gateways that sensed beacons and were able to send the Bluetooth advertising to a server via WiFi or Ethernet. Beacons started being used in industry for real time locating (RTLS) and IoT.

Bluetooth Mesh was adopted by the Bluetooth SIG in July 2017. This allowed beacons, or indeed any Bluetooth devices, to talk to each other such that a very large area can be covered with only one gateway at the edge. It’s now five years later and, apart from a few products related to lighting, Bluetooth Mesh hasn’t been popular.

Bluetooth Mesh

The main problem is that the Bluetooth Mesh standard was, for some reason, designed for usecases such as lighting that are low latency, low throughput and are mains powered. Bluetooth Mesh in beacons uses significant battery power and the throughput is too small for most IoT mesh applications having larger numbers of sensors.

Bluetooth Direction Finding was introduced with Bluetooth 5.1 in January 2019. The Angle of Arrival (AoA) variant works by having a beacon send out special advertising that is picked up by a multi-antenna locator.

Locator with multiple antennas

It’s now two and half years since the Bluetooth 5.1 release and some products have come to the market. However, most are evaluation boards that are not suitable for use in production. The software required to analyse the AoA radio data is very complex and performance-critical which has held back quick adoption.

LocationEngine™ Spectrum Analysis

Today, beacons are used in a vary large number of situations. For example, our customers use beacons for warehouse pallet tracking, factory job tracking, train company asset tracking, locating 2-way radios, healthcare asset tracking, tracking the elderly patients, man down SOS, lone working, evidence-based policing, smart offices, location-based gaming, car driving logging, facilities maintenance tracking, cargo temperature monitoring, student attendance monitoring and general IoT sensing. There are also a few consumer-facing uses but these tend to aid rather than spam consumers. Examples include restaurant table locating, museums and galleries.

In the future we expect we might see AoA and it’s sister technology Angle of Departure (AoD) mature. We are seeing beacons being used more in AR and immersive experiences so they might even have application in metaverses to help bridge the physical and virtual. It’s difficult to say how inflation and recession will affect innovation using Bluetooth. On the one hand companies will be spending less but on the other companies are seeking ways to measure and automate to save costs as part of Industry 4.0. Whatever happens, expect to continue to see beacons being used as part of larger solutions rather than the original premise of them being a (marketing) solution.

Read about PrecisionRTLS™

New F1 Beacon in Stock

We have the new, small KKM F1 beacon in stock. This beacon is different because it’s rechargeable, offering 4-6 months use per charge, based on 1 sec advertising.

It’s also waterproof to IP67 and has a button that can be used for SOS to send out different advertising. This beacon also has an accelerometer for motion triggered broadcasting.

It’s charged using a USB cable with a magnetic connector.

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Nordic Wireless Q Magazine

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:

  • A smart animal tracking and management system.
  • A handheld device used by students to answer test questions, record their attendance, answer surveys and provide class feedback.

There are also some interesting articles on:

  • How Bluetooth IoT sensors are enabling insurers to manage risks and mitigate claims by advancing accident prediction and prevention.
  • An explanation of the global chip shortage, manufacturing challenges and mitigations.
  • How IoT data can be used with AI machine learning to improve decision-making.

Read Nordic Semiconductor Wireless Quarter

Bluetooth AoA IQ to Location

Bluetooth direction finding uses locators that have multiple antennas. The antennas tend to be flat patches on a printed circuit board (PCB).

The antennas receive the same radio signal but at slightly different times based on the incident angle. This causes a phase difference in the received radio signal at each antenna.

Software is needed to process the radio signals from the antennas and calculate the incident angle. The radio signals are measured in terms of in-phase and quadrature components (IQ).

Processing the IQ signals isn’t easy because it requires taking account of the relative position of the antennas on the PCB, delays in switching between the antennas (there is only one radio receiver) and the use of complex-number arithmetic. The result is a power spectrum, the peak of which is the expected azimuth and elevation of the radio signal in two dimensions.

The finding of the peak also isn’t easy because it requires looping over lots of values to find the maximum. This is computationally time consuming especially as this has to be done many times per second for multiple locators.

Our LocationEngine™ is the first independent software to provide scalable IQ to location processing. It provides industry-leading accuracy, performance, security and reliability for Bluetooth® AoA direction finding. It’s currently compatible with the Minew AoA Kit but we are working with other manufacturers to support further hardware.

LocationEngine™ is designed in integrate into 3rd party systems to provide x, y, z and also area where locators cover more than one area. We supply PrecisionRTLS™ that uses this data to plot onto plans/maps, provide alerts and store historical data for later reporting.

Contact us about setting up a trial

Beacon Re-Designs

We are increasingly seeing beacon manufacturers providing updated versions of their beacons, not to provide extra functionality but to instead simplify the designs so as to reduce the component count or use fewer or cheaper semiconductors. The semiconductor manufacture crisis has resulted in a shortage of semiconductors that has resulted in component shortages and price rises. Beacon re-designs are an attempt by manufacturers to keep prices lower and in some cases prevent an existential crisis for a particular beacon model.

System on a Chip (SoC)

Some manufacturers are using simpler versions of the System On a Chip (SoC). These typically have less memory or have less functionality. Often the more-capable functionality wasn’t even used in the older beacon variant. Other times, things can be done in software that were performed in hardware. There’s also a trend to remove crystals that provide timing and instead perform this in software. Some manufactures are switching between SoC hardware manufacturers, for example from Nordic to Texas Instruments that requires a total hardware and software re-design.

Care needs to be taken when purchasing beacons especially when purchasing just a few samples and much later purchasing a larger quantity. Changes in hardware design mean that you won’t necessary get the same behaviour. This can affect aspects such as range and battery life. Doing things in software rather than hardware often affects battery use. At BeaconZone we are taking special care to ensure that current stocks of items behave as previously, if necessary specifying a particular variant when re-stocking.

Faraday Bags for Bluetooth

One of the most useful tools when deploying beacons is the Faraday Bag. A Faraday bag allows you purposely block beacons you haven’t yet placed so that they don’t affect testing. During development, it also allows you to simulate beacons or scanning devices going out of range without you even moving.

Faraday bags work by having a very thin gauze layer that block radio signals. Not all types of Faraday bag are the same. For BeaconZone Faraday bags, we had the manufacturer use two layers of gauze to block even the strongest Bluetooth beacons.

For any Faraday bag, the radio signal can leak through any larger holes in the gauze. This includes the opening that should be folded over and attached onto itself using the hook and loop fastening.

Faraday Bags

Beacon Signal Stability Observations

As previously mentioned, we perform signal strength and stability tests across beacons. The data feeds into our consultancy work. Here are some high level observations.

The following graph shows the standard deviation of the RSSI @ 1m, for some of our beacons, measured over a 60 second time period:


Smaller bars are better and represent beacons
whose RSSI varied the least over time.

We found that beacons belonged to one or two groups. Firstly those with very stable RSSI and secondly those with an RSSI that had a standard deviation between about 4 and 6 dBm.

Signal stability is more important when you are using the RSSI to infer distance, either directly from the RSSI itself or indirectly via, for example, the iOS immediate, near and far indicators. RSSI varying without a change of distance might cause more spurious triggering. However, you should keep in mind that environmental factors can often cause variation much larger than the 4 to 6 dBm found in this test. Moving obstacles, for example people, will cause significant variation in RSSI.

Bluetooth LE advertising moves pseudo-randomly between radio channels. The channels use different radio frequencies that, in turn, results in fading of the signal at different distances. We experienced and mitigated similar behaviour in our LocationEngine™. Different radio frequencies experience different constructive and destructive interference at different physical locations. Beacons that move more between channels can cause more rapidly varying received signal strength (RSSI).