Vehicle Parking Management Using iBeacons

There’s new research by Chi-Fang Chien, Hui-Tzu Chen and Chi-Yi Lin of Tamkang University, New Taipei City, Taiwan on A Low-Cost On-Street Parking Management System Based on Bluetooth Beacons (pdf).

Current smart parking systems are very expensive as they rely on image recognition and wireless magnetometers. The image recognition isn’t perfect and sometimes fails to acquire the identity of vehicles under poor illumination or due to obstruction of vehicle registration number plates.

Instead, a system has been developed using low-cost Bluetooth beacons. Beacons are installed in the vehicles and receivers are deployed along the roadside parking spaces.

Vehicle Parking Management System
Vehicle Parking Management System

The system uses Raspberry Pi for receivers and gateways. The Received Signal Strength Indication (RSSI) of beacons is processed, filtered and sent to a gateway. The system detects the occupancy of parking spaces and identifies the vehicles.

Smart On-Street Parking System
Smart On-Street Parking System Using iBeacons

It’s unfortunate the researchers didn’t consider Bluetooth Mesh for the receivers and gateways. It’s ideal for situations such as this where nodes are within range of each other and the data is small in size and sporadic. The use of Bluetooth Mesh would have reduced the hardware requirement considerably.

Read about Beacons and the Bluetooth Mesh

Getting the Most Out of Coin Cell Batteries

Nordic Semiconductor, the manufacturer of the system on a chip (SoC) inside most beacons, has a useful recent post by Jon Gunnar Sponås on Improve battery life in Ultra Low Power wireless applications.

It explains that while a battery has a fixed initial capacity, how you draw current from the battery affects how much of that capacity you get to use. At a relatively low constant current of 0.5mA you get most of the capacity while at 3mA you only get 60%.

For Bluetooth LE the current isn’t usually constant. Instead, it advertises at up to 7mA, for of the order of a milliseconds followed by a pre-set inter-advertising period between 100ms and 10 secs. This gives the battery time to recover.

The article explains how Bluetooth LE firmware should be designed to not turn everything on at initial startup so as to not stress the Battery unduly. It also mentions how it’s also wise to test the battery in the actual situation rather than relying on the battery mAh rating to calculate expected battery life.

Bluetooth Not Working After Windows Update

When doing a Windows Update it’s possible Bluetooth sometimes stops working. If you go to Device Manager you will see the Bluetooth icon with or without devices.

Windows sometimes removes hardware drivers or replaces them with ones that don’t work. To fix this go to Device Manager and click on the Bluetooth icon. If there are items, right click them and select ‘Update driver’. Click on ‘Search automatically for drivers’. If it doesn’t find anything, select ‘Search for updated drivers on Windows Update’.

If no Bluetooth items are showing, right click the computer name at the top and use ‘Scan for hardware changes’. If it still doesn’t work go to the web site support for your desktop/laptop manufacturer and look for and download the Bluetooth drivers.

Which Beacons for 2-way radio Motorola TRBOnet Plus?

TRBOnet is a 2-way radio dispatch system sold and supported by Motorola. It can use iBeacons to provide for locating where the Motorola radio GPS doesn’t work. This allows radios and hence people to be located indoors or undercover areas such as trees.

TRBOnet Plus beacons
TRBOnet Plus

TRBOnet Plus will work with any iBeacons. The ones with higher battery capacity tend to be used so that batteries don’t have to be replaced for years.

i3 Beacon for Motorola TRBOnet Plus
i3 Beacon for Motorola TRBOnet Plus

The i3 is popular for use with TRBOnet as it takes AA batteries that can be easily sourced and the unit has screw tags for permanent mounting. Some sites also use USB beacons that can be powered from the mains via USB power supplies.

If you use the i3, or any beacon using AA batteries, we recommend you use lithium AA batteries rather than alkaline. This will not only provide a longer battery life but will also provide better resilience at lower temperatures.

New iOS CoreBluetooth Mock Library

Nordic Semiconductor, the manufacturer of the System in a Chip in beacons and other smart devices has a new iOS CoreBluetooth Mock Library. The library allows an app to be used with dummy Bluetooth calls rather than real APIs.

The main use is for automated testing. If testing code on a server or test bed you want tests to run reliably and predictably so that you can get a pass or fail indication. Replacing the wireless part of the app allows other parts of the app to be tested.

The library also has other uses:

  • Taking screenshots without setting up a particular physical scenario
  • Developing code quicker through better repeatability
  • Developing code without need of a physical phone or tablet
  • Developing code when a Bluetooth peripheral isn’t available yet and/or is still under development

A caveat is that this library is for CoreBluetooth and not for CoreLocation. The former is intended for communication with devices that are not iBeacon. Apple forces you to use CoreLocation to detect iBeacons because they don’t provide the standard Bluetooth advertising via CoreBluetooth when seeing iBeacons.

The CoreBluetooth Mock Library is useful for detection of non-iBeacon Bluetooth devices such as fitness trackers, health monitors, Eddystone beacons and sensor beacons.

Developing for Bluetooth LE

If you are developing code for Bluetooth LE, a great place to start is the GitHub bluetooth-low-energy topic.

GitHub currently lists 877 public repositories that cover every operating system. This includes programming with Java, Javascript, C, Python, C++, Swift, Kotlin, C# and Objective-C.

In many cases it’s best to use the repositories to see how to do things rather than use the libraries themselves. Most, but not all, libraries are thin layers over operating system APIs. Most libraries don’t get updated and it’s otherwise easy to later get trapped into dependencies you don’t need, particular ways of working or old ways of using the underlying OS.

App cross platform frameworks are another source of problems when programming Bluetooth LE. They also aren’t updated often nor provide optimal Bluetooth APIs. If you wish to ease Bluetooth LE development and retain flexibility for future changes then use the native programming languages and libraries.

Social Distancing Beacons on BBC News at Ten

The BBC had a piece last night on the use of social distancing beacons at Florence Cathedral in Italy.

The beacons are worn by visitors and vibrate and flash when people get too close to one another. The reporter, Mark Lowen, said that it was the first use of the devices which might be true of that device model but not of social distancing devices in general.

Read about Beacons for Workplace Social Distancing and Contact Tracing

How to Attach Beacons

The electronics inside beacons tends to be very similar because they are based on chip manufacturers’ standard designs. Instead, the main differences tend to be the batteries and the case. When it comes to the case, how to attach the beacons is usually a consideration.

The most common way of attaching beacons is with a double sided sticker supplied with many beacons. 3M VHB is popular due to the strong hold. The sticker can be attached to smooth surfaces such as wall or the back of lanyard id holders.

3M VHB Sticker
3M VHB Sticker

When using stickers, removing the beacons from walls can damage the paint surface. Also, some installations need a more theft resistant solution. Other’s need to be attached to rough surfaces or used in rugged situations. In these scenarios look for beacons with screw mounting. The screw holes are also sometimes used to plastic tie lock beacons to structures such as cages or plastic boxes.

Beacons with screw mount

For wearable beacons, many have a loop that can be attached to a lanyard or keyring. There are also wristband form factors.

Wearable beacons

Finally, a few beacons have the option to use a magnet for attaching to metallic objects.

Magnetic Beacon
ABSensor N03 with Magnet

View all beacons

New Thin Beacons in Stock

We have two new thin beacons in stock. The Meeblue U1 and UL1 are only 4.8mm x 45mm x 25.5mm and weigh only 7g.

These beacons are similar to the iB001M in that they are particularly suitable for wearing by humans or animals. These new models have twice the battery power of the iB001M and use the more battery efficient Nordic Semiconductor nRF52 series system on a chip (SoC).

An accelerometer can be used to provide for motion triggered advertising. The accelerometer is only used for motion triggered broadcast and has adjustable movement threshold. They can also be set up to only advertise when the button is pressed. Advertising can be iBeacon, Eddystone UID, Eddystone URI or user defined. In addition, the UL1, has a light sensor that can be set up to cause the beacon to advertise when it’s either dark or light.