Category: Bluetooth LE

Bluetooth Classic vs Bluetooth LE

Beacons use Bluetooth Low Energy (LE). Some people confuse this with ‘Bluetooth Classic’ so here’s concise explanation.

Bluetooth Classic or, more technically, Basic Rate/Enhanced Data Rate (BR/EDR) is an older Bluetooth standard announced in 1998. Bluetooth Low Energy (LE) was introduced in 2010, as part of the Bluetooth 4.0 specification. It came out of Nokia’s previous Wibree technology.

Although Bluetooth Classic is older, it is not obsolete and is instead used for different types of applications such as streaming audio and video. Bluetooth Classic is used when transferring files by Bluetooth between devices, such as photos, videos, and documents. It’s also commonly used for hands-free calling in vehicles. Bluetooth Classic is also used in medical devices such as glucose meters, blood pressure monitors, and heart rate monitors to transmit data to smartphones or other devices. Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR) requires pairing, the process of establishing a secure wireless connection between the two Bluetooth-enabled devices.

Bluetooth LE is designed for applications that require lower power consumption and low data transfer rates such as fitness trackers, smartwatches, beacons and other IoT devices. It uses a different protocol for data transmission which allows it to achieve higher throughput using smaller packet sizes. Bluetooth LE does not need pairing.

Both Bluetooth Classic and Bluetooth LE use the 2.4GHz unlicensed frequency band which is part the industrial, scientific, and medical (ISM) frequency band. Bluetooth Classic and Bluetooth LE differ in how they use the frequency and can coexist together.

How to See Bluetooth LE Advertising on Android and iOS

To see Bluetooth LE advertising on smartphones, you can use a Bluetooth scanner app. These apps are available from the App Store and Google Play Store and can be downloaded and installed on your smartphone.

To use a Bluetooth scanner app, follow these steps:

  1. Open the App Store Google Play Store on your device and search for “Bluetooth scanner” or “Bluetooth advertising”.
  2. Select a Bluetooth scanner app that you want to use and install it on your device. nRFConnect is a well-known scanner, provided by Nordic Semiconductor, the manufacturer of the Bluetooth System-on-chip in most beacons.
  3. Once the app is installed, open it and enable Bluetooth on your device, if it is not already enabled.
  4. The app will scan for nearby Bluetooth devices that are broadcasting advertising packets. It will display a list of the devices it finds, along with their names and other information.
  5. You can tap on a device in the list to see more details about it, such as its Bluetooth address (only on Android), signal strength, and any advertising data that it is broadcasting.

In summary, using a Bluetooth scanner app is a simple and effective way to see Bluetooth advertising on an smartphones. These apps allow you to see the devices that are broadcasting advertising packets, as well as the data that they are transmitting.

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.