Category: faq

How Far Can a Bluetooth Beacon Measure Distance?

A common misconception is that beacons can measure distance. In reality, beacons, with the exception of some specialist social distancing beacons and sensor beacons with an additional distance sensor, are designed to send signals rather than receive them.

Instead, measuring distance happens on the receiving end. Devices such as smartphones are equipped to detect these beacon signals. When a beacon sends out its Bluetooth radio signal, the receiving device knows the received signal strength (RSSI). This RSSI can be used to infer the distance between the beacon and the device.

In the proximity of a few metres, the variation in RSSI is significant enough to deduce the distance with a reasonable degree of accuracy. However, as the distance increases, the variation in RSSI becomes less pronounced. This means that while you can determine if a beacon is close or far away, pinpointing an exact distance becomes challenging.

For example, the iOS programming API, CoreBluetooth, provides classifications for the detected beacon signals. These classifications are ‘immediate’, ‘near’, and ‘far’. They don’t give a precise measurement in metres or feet but rather a general idea of the beacon’s proximity.

In terms of maximum range, depending on the specific beacon, it can be detected from distances up to 50m or even 100m. However, as mentioned earlier, at these longer ranges, the RSSI doesn’t provide a clear indication of exact distance. Instead, it offers a more general sense of whether the beacon is nearer or farther away.

What is the Difference Between iBeacon and Eddystone?

iBeacon, a standard developed by Apple, was introduced in 2013 as part of the iOS 7. It’s based on Bluetooth Low Energy (BLE), a power-efficient variant of Bluetooth technology. The strength of iBeacon lies in its background support on iOS devices, which allows for easier detection of beacons.

Google introduced Eddystone in 2015. This protocol for beacons was developed to embrace a broader range of uses. Eddystone offers multiple frame types to cater to various data needs like URLs, unique identifiers and sensor data. One most distinctive feature of Eddystone was the Eddystone-URL, where the beacons could send out a web address. However, this has been limited by the discontinuation of Google Nearby in Android.

Despite the differences in their design and features, both iBeacon and Eddystone share common ground in their use of standard Bluetooth advertising. They send different data in the same standard Bluetooth advertising packets. This shared aspect of technology ensures that they can both communicate effectively to both iOS and Android.

While Eddystone’s versatile frame types and open protocol initially made it appealing, it has seen a decline since the discontinuation of Nearby in Android. Currently, most new systems requiring smartphone applications to detect a beacon opt for iBeacon.

However, when it comes to locating and detection using gateways rather than smartphones, iBeacon vs Eddystone becomes less relevant and the beacons’ Bluetooth MAC addresses are usually used. The advertising packets can instead be used for sensor data, for example, temperature and humidity.

View iBeacon Beacons
View Eddystone Beacons
View Sensor Beacons

Can I Set the Maximum Distance the Beacon Transmits?

Many people inquire about adjusting the transmission distance of a beacon. They often wish to either conserve battery or restrict the range at which a beacon is detectable.

While some third-party platforms and SDKs offer distance settings, it’s a misconception to think you can directly set the distance. What you’re actually adjusting is the transmission power, which in turn influences the transmission distance. But since this involves radio waves, which are prone to reflections and interference, it’s impossible to guarantee that a specific power will equate to a precise distance.

When using an app to detect beacons, you can employ the Received Signal Strength Indicator (RSSI) to focus on those within a desired range. However, it’s challenging to precisely correlate RSSI with the actual distance.

Some wonder if they can set the distance in terms of centimetres, similar to NFC. Typically, this isn’t feasible because even at their lowest power setting, most beacons transmit over a distance of about a metre.

Rather than asking if the transmitter’s distance can be minimised, it might be more practical to configure the receiver to disregard detections from further away. By using the RSSI value on the receiving app or another Bluetooth scanning device, you can filter out distant beacons. Specifically, you can dismiss detections with an RSSI below a certain threshold, allowing you to focus on detections within a centimetre range.

We have an article on Choosing the Transmitted Power.

Can Bluetooth Beacons Track Individual User Data?

Bluetooth beacons themselves are generally not designed to track individual user data. They are small devices that transmit a Bluetooth signal at regular intervals, which can be picked up by smartphones or other Bluetooth-enabled devices within a certain range. The primary function of a beacon is to broadcast its presence and certain identifying information such as a unique ID.

However, the apps on your smartphone that interact with these beacons could potentially collect and store data about your location or behaviour. For example, a retail store might use beacons to send promotional messages to your phone when you’re near a particular product. The app on your phone that interacts with the beacon could collect data on which promotions you’ve seen, how long you spent in a particular area of the store and other information.

While the beacon itself is not tracking you, the software that interacts with it could be. It’s essential to be aware of the permissions you’re granting to apps on your phone, particularly those that request access to your location services.

Is it Possible To Use One App to Manage All Beacons?

There are lots of brands of iBeacon and Eddystone beacon. Each brand has its own management app. We have often been asked,

“Is it possible to have just one app to manage different brands of beacon?”

While it’s technically possible, there’s no incentive for anyone to create such an app. Creating just one app to manage one beacon brand, across iOS and Android is significant effort in itself.

Google identified this problem and created the Eddystone Configuration GATT Service. The idea is that if manufacturers used just this, apps and beacons would be inter-operable. However, people want to configure iBeacon as well as Eddystone. Manufacturers also want to allow users to configure and read sensor data. Also, using Eddystone Configuration GATT Service software in all future beacons does nothing to help manage the large number of beacons that are already out there.

As of writing this, in 7 years since Eddystone Configuration GATT Service was published, no apps have been published that work with the Eddystone Configuration GATT Service. However, the Nordic nRF Connect app does understand some of the Bluetooth Characteristics to better read these kinds of beacons. There hasn’t been a rush for manufacturers to use Eddystone Standard GATT.

Back to the question. It looks like there will be a separate app per manufacturer for the foreseeable future.

The Manufacturer Site Says a Beacon Has a Particular Capability. Why Doesn’t the Version BeaconZone Sells Support This?

There can be several reasons why the specification for a beacon listed on our site doesn’t match that shown on a manufacturer’s web site or 3rd party sales platform.

  • Beacon descriptions on many sites are often written by non-technical staff and non-English speakers. This means that there can be misunderstandings and errors.
  • Some descriptions purposely over-fill descriptions with incorrect information or competitor’s product information so as to attract interest. The actual specification becomes clearer after you have asked the right questions or, in some cases, when you receive the beacons!
  • Some descriptions are of cloned products with dubious provenance rather than products from the original manufacturer.
  • It’s common for descriptions to mention optional features that are only available via manufacturing customisation. They are sort of saying the specification is possible, but you will find you have to pay a lot extra for a custom version.

We spend a long time assessing beacons and only list the features actually provided by the beacons we sell. We have a deep understanding of beacons that can be accessed via our support and consultancy services.

View Beacons

How to Read the AnkhMaway Sensor Data?

Since we have been selling the AKMW-iB003N-SHT  and AKMW-iB004N PLUS SHT we have been getting a few questions regarding accessing the temperature and humidity data.

You should first read the manufacturer’s SHT20 User Guide (username and password supplied with your beacon).

If you are connecting via GATT to read the sensor data then you will need to set the beacon to be always connectable. The way to do this is (for some strange reason) only shown in the iB001M user guide:

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So if you wish to transmit iBeacon and remain connectable, set the value to 0x82. Note that if you subsequently set the beacon ‘on’ or ‘off’ in the ‘simple’ configuration screen, accessed via the spanner icon (Android) or Configure option (on iOS), then this will overwrite your set value.

However, you might instead consider reading the sensor data from the advertising data which a) is much easier to program and b) uses much less beacon battery power and c) allows multiple apps to see the data at the same time.

There’s also an iOS example app in the BeaconZone AnkhMaway technical area.

MQTT vs HTTP for Bluetooth WiFi Gateways?

Bluetooth WiFi gateways offer MQTT and/or HTTP for sending data to servers/cloud services. We are often asked which should be used. HTTP is what’s used by your web browser to fetch and send data to web servers. In very high level terms, MQTT accomplishes a similar thing but is better optimised for mobile devices and the Internet of Things.

HTTP is very ‘chatty’ which means it’s more complex, code wise, to implement at the sending end and wastes a lot of data and processing power getting information from sender to receiver. You can think of HTTP as wrapping the data within lots other data that gets sent backwards and forwards. MQ Telemetry Transport Protocol (MQTT) came out of IBM, is now an ISO standard and uses lightweight publish/subscribe messaging. It requires a smaller code footprint at the sender and uses less network bandwidth. This matters most when you are trying to get the maximum transactions per second or are being billed for data use.

Bluetooth WiFi gateways are powered via USB and have reasonably powerful microcontrollers so MQTT’s efficient processing doesn’t matter that much. The more efficient processing is more applicable to apps running on mobile devices. For example, Facebook uses MQTT which saves battery life.

However, being lightweight, MQTT offers faster response times and lower data use than HTTP that, while not necessarily being of much of an advantantage for the BLE WiFi gateway, benefits the communications medium and server side. The communications medium, that can sometimes be cellular or be data constrained, uses (and possibly bills) less data. More crucially, the server can process more requests in less time. MQTT tends to be better when connectivity is intermittent, bandwidth is at a premium and throughput is critical.

In summary, MQTT has lower latency and is more efficient. Whether these are required advantages depends on your actual project. If you need more help, consider our development services.

Is There a Beacon That Works Without Bluetooth On?

We sometimes get asked if it’s possible that smartphones can detect beacons without Bluetooth being on. All beacons are based on Bluetooth LE that, in turn, relies on Bluetooth being switched on in the phone to scan for beacons. There’s no magic underling operating system mechanism on iOS nor Android that allows you to use Bluetooth without the user having Bluetooth on.

More users are leaving their Bluetooth on due to the proliferation of connecting with other devices such as cars, Bluetooth headphones and smart speakers. If you are writing an app you should take steps to detect if Bluetooth is on and prompt the user appropriately.

The phone and beacon industries need to better educate users that Bluetooth is no longer the heavy battery drainer it was in the early days of smartphones.

How Accurate is Bluetooth Direction Finding?

Bluetooth direction finding promises sub-meter accuracy. In practice, the accuracy varies depending on factors such as the locator hardware quality, radio signal noise, surfaces causing radio reflections, the accuracy of locator placement and beacon orientation. The sophistication of the location engine software in mitigating some of the aforementioned factors can improve the accuracy.

As a guideline, our Location Engine with the Minew G2/AR1 tends to find beacons with a maximum angular error range between 6° to 10°, depending on the above factors. The error in position due to an error in angle gets magnified with distance from the locator. Hence, the accuracy also depends on the distance between the locator and the beacon.

Here are graphs of error vs distance for 6° error and 10° error:

The above accuracies are for hardware such as the Minew G2/AR1 with PCB antennas 50mm apart. It’s expected that greater accuracies might be achieved with hardware having greater inter-antenna distances.

It can be seen that the sub-meter promise has caveats. We have some tips to help reduce angular errors. Averaging data, over time, also reduces angular error with the trade-off of increased latency of detecting location changes. As with all locating technologies, headline performance claims need to be carefully examined and are only achievable in particular situations.

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