Author: Support

What is iBeacon Measured Power?

Most beacons’ configuration app have a setting for iBeacon ‘measured power’ or ‘RSSI at 1m’. This doesn’t change the power output by the beacon. Instead, it’s a value that’s put into the advertising data that declares to receiving devices what the power should be at a distance of 1 meter from the beacon. Receiving devices such as smartphones and gateways can use this to help calibrate a calculation to determine the rough distance from the beacon.

iBeacon Measured power setting

You don’t usually change this value and it’s actually rarely used. In most cases the value is irrelevant and can be ignored. However, if your app or receiving device does use this value, it’s best to first do some tests to see what the power level is in your particular situation. Things like the physical environment, blocking and beacon orientation can affect the actual power level at 1m. Set the value according to your particular scenario.

Read more about transmitted power (as opposed to measured power)

Extending BeaconRTLS™ Reporting

BeaconRTLS™ has a myriad of uses across logistics, manufacturing, healthcare and facilities management. It tracks assets and people to locate them in real time and detect anomalies to improve operational efficiency. This also extends to IoT sensing using sensor beacons that measure temperature, humidity, movement, light, proximity and open/closed.

The system allows you to search for and map the location of beacons. You can set up screen and email alerts based on asset type, location and sensor data. But what if you need more than this?

BeaconRTLS™ stores historical information which provides for industry or scenario specific reporting. For example, recent customers have been asking for Covid specific reports such as room occupancy and who has been in the same room at the same time.

The BeaconRTLS™ API allows your systems or reporting systems to access the data. However, this is of less use for those who want to implement solutions quickly and easily. The tricky part is that we have found every customer tends to need different reporting. Up until now we have been creating ad-hoc reports on a case by case basis.

We have been looking to standardise how custom reports are created with BeaconRTLS™ to reduce effort, time and cost and allow more customers to create reports for themselves. To enable this we have integrated BeaconRTLS™ with Grafana.

Grafana is a free, commonly used open source platform that allows you to show data in custom ways using dashboards and panels. We are creating example Grafana reports for use with BeaconRTLS™ that our customers can use directly or modify for their own use.

Grafana reporting where a beacon has been

Contact us if you are interested in using BeaconRTLS™ and would like to take part in the pilot of BeaconRTLS™ with Grafana.

Understanding Bluetooth LE Reliability

We have previously written about Bluetooth LE on the Factory Floor and Why Bluetooth LE Scanning Doesn’t Always See Devices (the First Time).

There’s a new informative paper by Martin Woolley of the Bluetooth SIG on How Bluetooth® Technology Makes Wireless Communication Reliable. It describes in detail how radio collisions, multi-path propagation, time-dispersion, transmitter-receiver synchronisation, signal strength, receiver sensitivity and buffer overflow can collude to make radio communications unreliable.

The paper explains how Bluetooth modulation schemes, CRC checks, multiple channels, coded PHY, adaptive frequency hopping, flow control and the ATT protocol work to make Bluetooth LE reliable.

The paper also takes a look how Bluetooth Mesh has been designed to achieve reliable communication.

Solar iBeacons

We previously supplied solar beacons. These are beacons with a rechargeable battery topped up via a solar cell.

Solar iBeacon
Solar Beacon

Solar beacon’s weren’t popular and all the models we supplied are no longer manufactured. Some specialist solar beacon companies, whose models we didn’t supply, have also stopped selling beacons. So what happened?

Solar beacons seemed attractive in that they offered the prospect of not needing to change batteries. They weren’t that much more expensive so price wasn’t the reason for poor takeup. Instead, we believe these were the reasons:

  • Solar beacons were always the dumbest of beacons. The features in advanced beacons, such as sensors and advanced settings, never made their way to solar beacons. If you needed these features then the solar beacon wasn’t suitable.
  • While you didn’t need to change the battery because it was flat, the rechargeable battery still had an inherent lifetime of about 10 years. Given that some beacons’ batteries can last up to 5 years, the solar advantage wasn’t that great. Replacement batteries also cost considerably more than non-rechargeable.
  • Solar beacons with glass solar cells were much more fragile causing them to be more likely to be damaged in transit and use. The solar cell also needed to be kept clean which was a problem in some situations.
  • The rechargeable batteries in beacons tended to be LIR2032. Lithium rechargeable batteries suffer from non-use and once flat cannot be used. Beacons in storage required their batteries to be replaced.

In summary, solar beacons have too many problems that, on balance, outweighed what was a less than expected increase in battery life. For next generation self-powered beacons look to Wiliot who power beacons via energy harvesting. Instead of batteries, they use supercapacitors but even these have limited life.

Why Real Time Locating is Becoming More Popular

The recent Nordic Semiconductor wireless quarter magazine contained an article on positioning and real time locating systems (RTLS). RTLS is experiencing growth:

RTLS detects the position of people and assets in real time. Tags are attached to people or assets and the radio signals from the tag allow the location to be determined. The real time aspect is important because it provides the current position automatically, unlike barcode scans and and NRF tags that are only as up to date as the last successful scan. With older, manual, systems, people are lazy and forget to scan.

A complete RTLS system comprises of readers, tag/sensors, application software and communications/network infrastructure.

Asset tracking is being used in industry verticals such as healthcare, defence, education and manufacturing. It commonly tracks tools, equipment, pallets, sub-assemblies, jobs and completed goods.

From Allied Market Research

People tracking has tended to be used more in education and health where the security of individuals is more important than privacy concerns related to tracking people.

RTLS growth is being driven by the benefit of real time tracking allowing processes to be much more efficient. Effort and time is saved when things and people can be found quickly. Alerts notify abnormal conditions to provide for proactive actions. Reports track long term trends to allow identification of patterns that can be used to change processes to improve efficiency.

Bluetooth is popular for use with RTLS because tags and readers are inexpensive compared to other technologies. Bluetooth also works indoors where GPS fails. Unlike other technologies, Bluetooth LE tags have a long battery life of up to several years. There are also tags that perform sensing and Bluetooth LE is suitable for use in electrically noisy environments. Bluetooth also integrates with Bluetooth LE devices such as smartphones, tablets, laptops and desktops.

At Beaconzone we are seeing two new trends in use of RTLS. The first is using RTLS for multiple purposes. Customers often come to us wanting to solve a particular problem but later find the RTLS has a multitude of uses and benefits. This is where a closed solution offering, for example, a lone worker solution, won’t be so flexible.

Established real-time location system market players are shifting from closed solution offerings to including best-in-breed components in application layer

Allied Market Research

The second trend, brought on by Covid, is the tracking of office workers. What might have used to be seen as an invasion of privacy is now being seen as an essential way to monitor room occupancy and determine who has been in the same room as someone else when a person tests positive for Covid.

Read about BeaconRTLS

Read about BluetoothLocationEngine™

Q3 Nordic Semiconductor Wireless Q Magazine

Nordic Semiconductor, the manufacturer of the System on a Chip (SoC) in many beacons, has published the latest issue of Wireless Quarter Magazine. It showcases the many uses of Nordic SoCs.

It showcases a gym management platform using beacons that analyses equipment and zone use. It also mentions the nRF52 SoC, used in beacons, being used in

  • MEZOO’s ECG monitor that detects heart arrhythmia
  • Xiaomi’s Bluetooth LE smart door lock
  • M Lura Health’s 1000 tooth sensor
  • Escort’s fuel level sensor

Juniper Research reports on how the pandemic is accelerating use of IoT:

IoT connections driven by early industrial deployments and pandemic-driven telemedicine applications are projected to reach 83 billion by 2024, a 130 percent growth rate

There are also articles on using tech to prevent deforestation, wellness tech, smart street lighting and precision positioning.

Why Bluetooth LE Scanning Doesn’t Always See Devices (the First Time)

Bluetooth devices such as beacons periodically advertise data according to a pre-defined format such as iBeacon or Eddystone. The advertising is very short, of the order of 1ms. Listening devices such as apps or gateways scan for a defined time, the scan window, periodically every scan interval. The scanning scan window is usually less than the scan interval to conserve power because scanning is power intensive.

From Analysis of Latency Performance of Bluetooth Low Energy (BLE) Networks

While scanning nearly always sees a nearby device, there can be times when it isn’t seen due to physical and technical reasons. Radio signals can get blocked and reflected in ways that cause them not to be received. Also, if two Bluetooth devices happen to advertise at the same time then the received radio signal is corrupted. It’s also possible that because scans stop and start, the advertising happens when the scan isn’t running.

In practice the chance of non-detection happening is small. The chances of it happening again, the next scan, are very unlikely. If a beacon isn’t seen on the first scan it’s usually seen on the second (or third) attempt.

Bluetooth has some mitigations to help reduce the occurrence of the above mentioned situations. The advertising and scanning happens on multiple channels (frequencies) 37, 38 and 39 to reduce the affect of interference from other devices. Also, the advertising interval isn’t fixed and varies by a random amount, the advertising delay, for up to 10ms, to prevent two (or more) devices’ advertising continually colliding.

The consequence of scanning possibly not seeing beacons (the first time) is that solutions using apps or gateways must not rely on only one scan to make decisions on the absence of a beacon.

iBeacon Deployment Parameters for Locating

Researchers from the The Hong Kong Polytechnic University have a new paper on Performance Evaluation of iBeacon Deployment for Location-Based Services in Physical Learning Spaces (pdf) that tests environmental and deployment factors, indoors and outdoors, related to using ibeacons for locating. It provides recommendations for iBeacon deployment in terms of location, density, transmission interval, fingerprint space interval and collection time.

iBeacon deployment

The paper provides a great introduction to positioning using beacon received signal strength (RSSI). It describes trilateration and fingerprinting methods for determining location.

Key insights are:

  • High temperature, strong wind and blocking by pedestrians degraded the signal strength.
  • Pedestrians traffic blocking the line of sight caused the most signal attenuation and variation.
  • High air temperature caused significant increase of packet loss that affected the RSSI.
  • Strong wind reduced the signal strength but didn’t affect the stability of signals.
  • Trees and nearby vehicle traffic didn’t have any negative effects on signals.
  • Lower error rates were observed when beacons were deployed on the ceiling as opposed to on the wall.
  • Positioning accuracy improved with ceiling placement due to the reduction of obstructions.
  • If ceilings are too high or ceiling deployment is impracticable wall mounted iBeacons should be placed as high as possible.
  • For fingerprinting, sample at 2m grid intervals for 6s to 10s at each point. Avoid having too many beacons as this won’t improve the positioning accuracy. A transmission interval of 100ms is detrimental to the positioning accuracy. 417ms is better.
  • For fingerprinting, positioning accuracy varies greatly according to the what is in the room.

The paper mentions that beacon UUID, major and minor are used to uniquely identify beacons. While this is true in the context of detecting using apps, most locating systems use gateways. Gateways use the Bluetooth MAC address to uniquely identify beacons and the advertising type, iBeacon, Eddystone or other, is irrelevant. Using gateways as receivers is also a solution to the problem of variability in receiving capability across smartphones.

The study only considered one beacon type and two receiving smartphones. At Beaconzone, we recommend experimenting with the actual hardware in the actual environment as, being wireless radio, optimum settings and can vary considerably.

Read about location accuracy

Read about Using Beacons, iBeacons for Real-time Locating Systems (RTLS)