Category: Bluetooth LE

The Advantages of Bluetooth Over RFID

Bluetooth and RFID (Radio-Frequency Identification) are both wireless communication technologies that are used for a variety of applications, including asset tracking, data transfer, and access control. While both technologies have their own advantages and disadvantages, some of the main advantages of Bluetooth over RFID include:

  1. Range: One of the main advantages of Bluetooth over RFID is that it has a longer range. Bluetooth devices can typically communicate with each other over distances of up to 30 meters (100 feet), while RFID tags have a much shorter range of only a few centimeters. This means that Bluetooth can be used for applications where a longer range is required, such as tracking the location of assets in a warehouse or building.
  2. Data transfer: Another advantage of Bluetooth over RFID is that it can be used for bi-directional data transfer, allowing devices to both send and receive data. In contrast, RFID tags are typically only capable of transmitting a limited amount of data, such as an identification number or other simple information. This makes Bluetooth a better option for applications that require more complex data transfer, such as IoT sensing, transferring files or images between devices.
  3. Immediacy and reliability: RFID usually requires manual swiping while Bluetooth is continuously providing updated location. Not having to rely on manual swipes makes Bluetooth more immediate and reliable.
  4. Security: Bluetooth also offers better security compared to RFID. Bluetooth devices use a pairing process to establish a secure connection before exchanging data, while RFID tags do not have this capability. This makes Bluetooth a more secure option for applications that require sensitive data to be transferred, such as financial transactions or access control.

Overall, while both Bluetooth and RFID have their own advantages and disadvantages, Bluetooth offers a longer range, better data transfer capabilities, more immediacy and reliability and improved security compared to RFID. This makes it a better choice for applications that require these features.

View Bluetooth Beacons

Fixing Poor Bluetooth Beacon Radio Signals

In most cases beacons ‘just work’ but it’s sometimes the case that beacon detection is erratic. A beacon might be detected but not all the time. Problems can be due to the strength and/or quality of the received signal. The first step is to quantify the signal strength so you can measure it at various distances and beacon positions. The post on Testing if a Beacon is Working explains how to use an app such as nRF Connect to measure signal strength (RSSI) using a smartphone.

nRFConnect detecting beacons

If you are not getting a large enough signal at longer distances then try increasing the transmit power. This is labelled ‘Tx power’ in most setup apps. Make sure it is at least 0dBm and increase it to +4dBm for a longer range. Note that changing from 0dBM to +4dBm will reduce battery life by over a half. Another option is to use a beacon with a longer range.

Minew setup tx power

Another reason for poor detection is blocking of the line of sight. The degree of blocking depends on the blocking material. The post on What Can Block Beacon Signals? provides more information.

If beacon detection is erratic irrespective of the distance you need to look into the relationship between how often the beacon is advertising vs how often the receiver is listening. The post on Why Bluetooth LE Scanning Doesn’t Always See Devices (the First Time) provides a detailed explanation. This kind of problem can often be solved by decreasing the advertising period. This is sometimes labelled ‘Advertising interval’ as in the above example screenshot. Again, reducing this by, for example, a half will halve the battery life. It needs to be 600ms or less if iOS is to reliably detect beacons.

It’s rare but there’s also the possibility of too many Bluetooth signals advertising at the same time. You can learn more in the articles on Managing Bluetooth LE Advertising Congestion and The Affect of the Number of Beacons on the Detection Time.

New Bluetooth Location Services Infographic

The Bluetooth SIG, who manage the Bluetooth standards, have a new infographic on location services based on figures from ABI Research.

Some insights:

  • The leading location services category is Retail and Services at 62%.
  • Smartphones are helping drive adoption.
  • There will be 35% compound annual growth in Bluetooth location devices from 2022 to 2026.
  • There will be 547,000 Bluetooth RTLS implementations by 2026.

Learn about BeaconRTLS™

View Bluetooth Beacons

Using Bluetooth LE with React Native

There’s a useful new article at Stormotion on how to use Bluetooth LE with React Native. The article explains the difference between Bluetooth LE and Classic Bluetooth and details the differences between the two main libraries when integrating Bluetooth LE into React Native apps.

The article also provides information on what apps to use to test Bluetooth LE and has insights on how to avoid the common problems.

Detecting Malicious Bluetooth Trackers

There’s new research from University of Washington on BLE-Doubt: Smartphone-Based Detection of Malicious Bluetooth Trackers University of Washington (PDF).

Stalkers can hide Bluetooth beacons on targets’ clothing or in vehicles so as to monitor their locations. The researchers created an open-source method of detecting maliciously deployed Bluetooth beacons.

The algorithm detects malicious devices within a few minutes. The software scans for Bluetooth advertisements and stores a history so that an alert can be created if a beacon is following the same route as the user.

iBeacon, Altbeacon, Eddystone, Tile, Chipolo, Spot, and AirTag are all detected with AirTags the greatest challenge due to rotation of their MAC addresses between every two hours and once a day and their erratic and unpredictable advertising.

The app doing the scanning causes heavy smartphone battery use. The smartphone lost between 5% and 10% of its battery per hour during active scanning.

View Tracker Beacons

Measuring Distance with Bluetooth LE

There’s a useful recent Webinar at Nordic Semiconductor on Measuring distance with the Nordic Distance Toolbox. The Nordic Distance Toolbox (NDT) provides ways to measure the distance between two Nordic SoCs. An SoC (System on a Chip) is the main chip found in beacons and Nordic is one of the main manufacturers.

The webinar covers the theory of distance measurement based on radio phase, RSSI, Round Trip Timing (RTT) and processing such as Inverse Fast Fourier Transform (IFFT). Practical performance is measured and the conclusions are:

  • Phase based ranging gives best accuracy but is range limited maximum range is limited to 8 to 10m (in the office environment)
  • RTT gives lower accuracy (Standard deviation 3.8m) but can be used up to the maximum Bluetooth connectivity range that can be several 100 metres
  • High precision with a median 3 filter gives the best accuracy (Standard deviation of 37cm)

The presentation PDF is also available.

Using the SoC radio to determine distance is power-hungry, relatively complex to develop and, as the above shows, doesn’t result is very good accuracy. If you want to measure distance it’s simpler, more accurate and more battery-efficient to use a dedicated hardware-based distance sensor. For example, the IBS03R uses a dedicated time of flight (TOF) sensor to achieve accuracy of +-25mm and a battery life of 1.8 to 2.8 years.

New Bluetooth LE Book

There’s a new book Develop your own Bluetooth Low Energy Applications by Koen Vervloesem. It introduces Bluetooth Low Energy and shows how to programming with Python and the Bleak library on a Raspberry Pi or PC, with C++ with NimBLE-Arduino on Espressif’s ESP32 development boards and with C on Nordic Semiconductor’s nRF52 boards.

Koen has a blog where you can read an abridged version of the book. He explains Bluetooth Low Energy, the Bluetooth stack, advertising and connecting. You can also view the samples on GitHub.

Python and Bluetooth on Linux

Barry Byford has a new blog post on D-Bus and Bluez. It documents his experiences creating a BLE central client on Linux. Barry deliberates over dbus-python and pydbus. He then provides an example how to create a Bluetooth GATT connection, converting D-Bus typed data to python types and interacting with a BBC micro:bit.

While you are on Barry’s site, read his notes from workshops and further notes on using Bluetooth.

New Bluetooth Low Energy (LE) Primer

The Bluetooth LE specifications are very technical and not very approachable for those wishing to use, rather than create, devices using Bluetooth. Bluetooth SIG, who manage the Bluetooth specifications, have a new document by Martin Woolley titled The Bluetooth® Low Energy Primer. This is the definitive guide to better understanding Bluetooth LE.

This free document covers the history of Bluetooth LE and explains the various layers in the Bluetooth stack. It describes the protocols and profiles that make up Bluetooth LE. It also provides pointers to study guides, papers, hands-on resources and formal specifications for further reference.