Author: Support

New Nordic Wireless Quarter 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:

  • Leak detectors that harvest energy from water
  • A smart lock that can be retrofitted to most doors
  • Future wearables that can detect Alzheimer’s disease

There are also articles on how IoT is forecast to save eight times more energy than it consumes, a piece on smart homes and an in-depth explanation how advanced wearables are moving beyond fitness to provide better health outcomes.

Read Nordic Semiconductor Wireless Quarter

Beacon Battery Size, Type, Capacity and Life

After project rollout, human effort used in regularly replacing batteries can be significant and the human resource cost of doing so can dwarf the actual cost of the beacons. Hence, unless it’s a temporary scenario it’s best to specify beacons with as large a battery capacity as possible. Beacons with smaller capacity batteries are only suitable for short trials, temporary events or use during development.

While BeaconZone stocks a very large range of beacons, we purposely haven’t stocked any beacons with batteries smaller than CR2032 because the battery life of CR2025 and CR2016 beacons is usually too short. All our beacons use either CR2032, CR2450, CR2477 or AA batteries.

How long a battery lasts depends not just on the battery capacity but also the transmitted power,  advertising interval and beacon processor chip type. This article only considers the battery itself.

Battery capacity is measured in mAh. The mA part (without the h) is the unit of current. As an example, a CR2477 battery typically has a capacity of 1000 mAh which means it can supply 1 mA for 1000 hours or, for example, 2mA for 500 hours. However, most beacons only use tens or hundreds of µA when transmitting, where 1 µA is 1000 times smaller than a 1 mA. Also Bluetooth beacons only transmit for a few milliseconds (1 ms = 1/1000 sec) at a time so you can see how a coin battery can last a long time.

Here are the main battery sizes and their typical mAh rating:

CR2032 = 250 mAh
CR2450 = 500 mAh
CR2477 = 1000 mAh
2 x AA = 2200mAh (Alkaline), 3000 mAh (Li)
4 x AA = 4400mAh (Alkaline) or 6000 mAh (Li)

A beacon such as the i3 containing 2 Lithium batteries can last 3x one with a CR2477 battery and 24x one with a CR2032 battery. This gives a battery life of up to 3 to 4 years depending on other configuration parameters.

Lithium AA batteries such as the Duracell Ultra Lithium and Energizer Ultimate don’t just last longer than Alkaline AA batteries. Their voltage also doesn’t vary so much with temperature which might be a consideration if your rollout is outdoors.

Museum, Visitor Space Case Study

We have a new case study on our consultancy for Royal Museums Greenwich on the Cutty Sark.

Royal Museums Greenwich wanted to locate visitors as part of their forthcoming Cutty Sark Alive Augmented Reality (AR) experience.

Use our consultancy to help prevent problems that should have been known prior to commencement. Otherwise, ‘unknown unknowns’ can lead to project failure or force pivoting in less desirable directions. A small initial study prevents expensive and embarrassing mistakes.

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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:

beaconsignalstability

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).

Using AI Machine Learning with Bluetooth Angle of Arrival (AoA)

There’s new research from Universities in Piraeus, Greece and Berlin, Germany, together with U-Blox AG in Switzerland who create Bluetooth Angle of Arrival prototyping boards on Deep Learning-Based Indoor Localization Using Multi-View BLE Signal.

Processing of Bluetooth Angle of Arrival usually requires radiogoniometry spectral analysis of radio in-phase and quadrature-phase (IQ) signals in order to then determine location by triangulation. Instead, this paper proposes machine learning of IQ and signal strength (RSSI) data from multiple anchor points to determine location. AoA processing also uses distributed processing across the anchors to improve performance.

The developed machine learning models were found to be robust against modifications of room furniture configurations and materials and it’s therefore expected that they have high re-usability (machine learning generalisation) potential. The system achieved a localization accuracy of 70cm.

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RTLS in Oncology Operations

The Future of Personal Health has an article on Innovate Oncology Operations With RTLS Patient Flow Technology.

The article explains how 75% of cancer program management cited workflow inefficiencies as the most concerning bottleneck to patient care delivery. There are problems with patient flow that stresses care teams and ultimately jeopardises the safety of patients.

RTLS can be used to know and optimise how long patients have been waiting, their stage of care, who has seen them and who they need to see next. This reduces both patient and staff frustration. The article claims it is possible to increase increase capacity by 10% without adding physical space.

While mentioned in an oncology setting, this is just as applicable to other health settings where patients are waiting.

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Proof of Concept for Beacon Projects

It’s easy to buy into an idea and commit significant resources only to find very late on that a project is overly difficult or impossible to implement. We see too many companies only come to us after they have gone a long way down a particular road only to discover they made a big mistake early on. It might be, for example, they have heavily committed to the wrong beacon, wrong platform or have assumed something on one of the mobile platforms. They didn’t do their research. Often we can help them get on the right track but sometimes not.

We always recommend organisations research upfront. Test risky areas. Create a low cost proof of concept exercising risky areas. A proof of concept is the implementation of a small subset of the whole system to prove implementing the whole thing is possible. Good candidates for functionality for proof of concepts are specific usecases, scenarios or user stories. Choose specific usecases to exercise what you think might be the most difficult or unknown parts of the system.

Proof of concepts provide a feel for the development effort that will be required to develop the complete system thus giving an indication of the project’s cost and the financial viability of the project.

It’s also possible to create proof of concepts that include business goals. Think ‘proof of value’ rather than ‘proof of concept’. Proving a project has value to stakeholders can help unlock realistic funding for development of the complete project.

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Bluetooth Positioning on Ships

There’s new research from College of Information Engineering, Shanghai Maritime University, China on BSSH: Bluetooth Indoor Positioning Strategy for Ship Cabin Based on Hierarchical Area.

The locating and monitoring of ship crew is an important part of ship safety when it comes to adherence to duty regulations. The paper shows how Bluetooth works within the complex electromagnetic and spatial structure of a ship.

The research proposes a BSSH positioning system using fingerprinting that divides the ship up into hierarchical areas.

The BSSH system eliminates the affect of distant beacons on the location results thus reducing the computational effort and improving accuracy.

The system demonstrated better results than a traditional KNN positioning algorithm. It had higher positioning accuracy, better stability and an accuracy rate of more than 80%.

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Bluetooth Market Update

The Bluetooth SIG, who manage the Bluetooth specifications, have a new market update that provides information on the Bluetooth ecosystem. The most interesting and pertinent segment for our customers is location services:

Location service device shipments are expected to have 25% compound annual growth over the next five years according to ABI Research:

Commercial RTLS are being driven by recent inventory and logistic challenges:

‘Retail and Services’ at 62% is surprising as we would have expected ‘Warehouse and Logistics’ to be the larger segment.

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