Author: Support

What Can Block Beacon Signals?

We often get questions asking what kinds of things can block Bluetooth signals and enquiries about the relative blocking of different materials.

Metal obstructions or metal-based surfaces such as metal-reinforced concrete cause the most blocking followed by other dense building materials such as plaster and concrete. Next comes water that you might not think would be a problem but, as people are made up of 60% water, bodies blocking Bluetooth signals can be a significant factor. Least blocking are glass (but not bulletproof), wood and plastics.

Blocking can be caused by wireless noise as well and physical obstructions. This includes electrical noise from other electrical equipment as well as interference from devices using the same 2.4GHz frequency. WiFi on 2.4GHz causes negligible interference.

In extreme cases, a very large number of Bluetooth devices can cause interference with each other because only one can advertise at a time without there being collisions and hence lost data. The maximum number of Bluetooth devices depends on how long and how often the Bluetooth devices transmit. It also depends on whether devices are just advertising or additionally using GATT connections. Bluetooth also has adaptive frequency hopping that helps reduce packet interference.

We have a deeper analysis of interference in the post on Bluetooth LE on the Factory Floor.

Bluetooth Low Energy Packet Formats

In most cases, it’s possible to use beacons without knowing the exact data format of the advertising. It’s usually possible to specify only a few values such as iBeacon UUID, major and minor and the devices and listening apps work together. In some instances it’s necessary to know Bluetooth LE packets formats, for example, to implement your own code.

The Bluetooth packet formats are defined by the Bluetooth specifications but specifications aren’t always the fastest and easiest to understand. There’s a new presentation on SlideShare on Bluetooth Low Energy (BLE) Packet formats.

Winfred Lu from STMicroelectronics describes Link layer, advertising, data channel and physical channel packets.

Read about Using Bluetooth Low Energy (LE)

Tracking Hand Power Tools Using Bluetooth Beacons

DEWALT have a new Bluetooth beacon, the DCE042, that provides tracking of hand power tools.

It works with the Tool Connect System, on web or mobile, to track, assign, and manage tools to save time, improve productivity and reduce costs due to lost tools.

Several years ago we provided consultancy for a similar system developed by AddMobile (since been acquired by Infobric Group). The use of beacons in construction poses challenges related to the internal physical construction of beacons beyond them having to be rugged and IPX rated. Care also needs to be taken to design systems for efficient battery use so that device battery management doesn’t become a burden for users.

Learn More About Beaconzone Consulting

Beacons for Restaurant Order Apps

A growing number of restaurant ordering apps, such as Voolsy, use Bluetooth beacons to determine location.

Voolsy detects restaurants through iBeacons, lets customers explore digital menu, customize their order and place it with just a few taps across thousands of locations. Voolsy reduces your waiting time to get attention of waiter from minutes to seconds

Voolsy supports both ordering and payment for retail locations such as restaurants, food courts or cinemas using beacons. It also provides Voolsy cashback and other exclusive offers from partnered restaurants.

Why Doesn’t the Manufacturer’s Configuration App Connect?

When in typical use, it’s not necessary to connect to a beacon. A beacon just advertises and is detected by a smartphone or Bluetooth gateway. However, to initially set up a beacon you usually connect via a smartphone app. The app might not connect for a number of reasons. Here are some tips:

  • Most beacons need to be put into ‘connectable’ mode. For example, for most AnkhMaway beacons this means tapping them sharply on a table until they ring – they remain connectable for 45 secs and once connected remain so until you have configured the beacon. For Axaet and Meeblue beacons they stay connectable for a few minutes after turning them on.
  • Make sure you are connecting to the correct beacon. This is especially important if you are seeing multiple Bluetooth devices in the list. For example, we had one customer who hadn’t removed the plastic battery slip and had been trying to connect to some other Bluetooth beacon/device.
  • Connecting, via what is a wireless interface, might not work first time. While most connections do happen first time, there can be radio interference and radio signal reflections that can cause the connection to fail. Some configuration apps re-try if the first connect fails while others don’t. Make sure you have tried a few times before concluding a particular scenario doesn’t work.
  • Some phones have a faulty Bluetooth beacon stack. That’s the Bluetooth software built into your phone. While you might be able to view the beacon, connecting to it to change settings uses more advanced functionality that’s sometimes faulty. Over time, we have discovered about 5% of our customers have such problems, more so on Android. It’s a much more common problem than a faulty beacon. You can isolate this possibility by trying a different phone and/or different phone OS type.
  • Don’t try connecting from more than one phone at a time. When connected, that phone has exclusive access to the beacon and other phones won’t be able to see the beacon and connect.
  • Make sure you are using the correct password to connect. It’s not the password on the sticker which is the web site technical area password.
  • Try rebooting your phone to reset the internal Bluetooth software.
  • Try resetting the beacon by removing and replacing the battery (where possible). This isn’t the same as turning off via a button press which usually only puts the beacon into hibernation and doesn’t restart the device.
  • Some configuration apps have known bugs. Read the BeaconZone technical area for your particular beacon manufacturer where we document known problems and workarounds.
  • The beacon could be faulty. This is actually a very rare occurrence and you should initially be considering other more likely possibilities (above). You can isolate this possibility if you have another similar beacon. Please contact us for replacement if you conclude you have a faulty beacon.

Learn About Indoor Positioning

There’s a recent paper Review of Indoor Positioning: Radio Wave Technology that provides a great overview of indoor positioning technologies.

From a hardware perspective it covers, RFID, UWB, Bluetooth, ZigBee, IR, WiFi, ultrasonic and hybrid systems. There’s a useful comparison table of the various technologies:

The paper describes methods of using radio signals to determine position such as RSSI ranging, trilateration, angle of arrival (AOA), round trip time of flight (RTOF), phase of arrival (POA) and time of arrival (TOA).

Trilateration

It also describes methods such as fingerprint localization.

Why Doesn’t The Beacon Achieve The Specified Range?

The distance that a beacon can transmit is shown in the specification tab for each beacon. This is the maximum range specified by the manufacturer at maximum power under ideal conditions.

Here are some tips if the range is less than expected:

  • Make sure the beacon is operating in normal rather than configuration or connectable mode. Some beacons transmit differently or only for a limited time when they are in connectable mode. For example, with AnkhMaway beacons, make sure the mode has been set to ‘On’ either in the configuration app settings or via service/characteristic parameters.
  • Make sure the beacon is set to 0dBm transmit power (or higher) rather than a negative value that indicates the beacon is to transmit with reduced power.
  • Re-orient the beacon. Most beacons have antennas on the printed circuit board that have differing transmission characteristics depending on their orientation to the observer and whether they are shielded by other components such as the battery. Experiment with different orientations in each of the three dimensions.
  • Try a different observing device (phone). Different phones have different receiving characteristics.
  • Try at a different place. In rare circumstances, the area might be congested with 2.4GHz interference from other beacons, WiFi or other equipment. The area might have particular radio frequency (RF) blocking or reflective qualities.
  • If you can, try a different beacon of the same model to isolate whether it’s a faulty beacon.

The maximum specified range is rarely achieved for any beacon although there have been a cases where we have found beacons to be better than the specification.

All manufacturers, not just those whose beacons we sell, tend to specify the optimum range, outdoors, with no radio interference. You will experience reduced range indoors where there are radio reflections and obstacles. If you need a long range under all circumstances then we recommend you over-specify the beacon range and perhaps look at beacons with an ultra-long range.