Understanding Sensor Beacon Accelerometer Data

In this post we will take a look at data from the INGICS iGS01RG beacon.

The x axis is time. You can see the x, y and z values, every 100ms, over time. The y axis is normalised between -1 and -1 for use in our SensorCognition Edge device. The chart is for when the beacon has been moving, followed by a stationary period. Notice how the orange line continues to show acceleration even though the beacon isn’t moving. This is caused by gravity.

In this chart the beacon has been flipped over and the orange line now shows a constant negative acceleration.

A good thing about the presence of a constant offset in one of the x y z inputs is that it can be used to help determine the orientation of the beacon. The less desirable aspect is that the offset significantly complicates using the x y z to determine types of movement such as human gestures.

Such complex data problems are more easily solved using AI machine learning than trying to write a traditional algorithm to make sense of the data.

Here’s an example of output from a SensorCognition Edge device trained with up and down movement and left and right movement. In this case, the output 227 is showing the beacon is moving left and right.

Read about SensorCognition

Quick Detection of Man Down with MOTOTRBO™, TRBOnet and iBeacons

TRBOnet is control room software for Motorola MOTOTRBO™ two-way radios. When used with iBeacons, it allows mapping of 2-way radio locations.

The location update rate depends on the degree of radio congestion. The more radios there are the greater the congestion. The use of iBeacons also increases radio congestion as they cause more location packets to be sent. This can become a problem in larger 2-way radio/beacon rollouts.

In cases where a 2-way radio can see more than one beacon, the TRBOnet server uses the relative signal strengths of the beacons to determine the nearest beacon. In the case of radio congestion, the location updates for the two or more beacons might be two far apart, in time, to allow an accurate location to be determined. In congested situations, location updates used for geofencing or man-down might also come in far too late, say 5 minutes late, to provide timely alerts that someone has entered/exited an area or has fallen.

Neocom Software, the authors of TRBOnet, have introduced an Option Board based solution (pdf), that fits in the 2-way radios, that solves these problems. It monitors beacons every 3-5 seconds instead of the standard 30 seconds. It does the comparing of beacon signal strength at the 2-way radio rather than at the server to reduce the number of sent location packets. It intelligently sends location packets as the user changes zone rather than continuously.

The configuration guide (pdf) explains how the option board can be set up to detect events such as man down, geofencing, lone worker (no activity), no movement, crash detection and speed limit.

Are you an established 2-way radio company?
Contact us for advice on which beacons we have supplied for use with TRBOnet.

The Demise of Unsolicited Marketing Using Beacons

There’s a new article at DIGIDAY on how Apple’s new privacy features have further rattled the location-based ad market. The iOS location and Bluetooth permission changes have caused users to opt-out of marketing messages:

Right now opt-in rates to share data with apps when they’re not in use are often below 50% … Three years ago those opt-in rates were closer to 100%

Benoit Grouchko, Teemo

80% of those users stopped all background tracking across their devices

Location Sciences

Google’s discontinuing support for Android Nearby notifications and Apple’s tightening of permissions have caused the demise of unsolicited marketing using beacons. This is understandable because unsolicited marketing is seen by end-users as intrusive and creepy.

However, the iOS and Android mechanisms are still there for more worthy applications such as visitor space usecases that need to provide location based information. For these types of application, there’s the need for good app onboarding explaining location and Bluetooth usage in order to provide the location-based information that the end-user is requiring.

While unsolicited marketing was the key benefit when iBeacon was first announced, the use of beacons has since diversified into less contentious and more practically useful areas such as real time locating (RTLS), IoT Sensing and insights through machine learning.

Bluetooth in Healthcare

The Bluetooth blog has a recent post on 4 Reasons to Use Bluetooth in Your Healthcare Facility. It explains some advantages of Bluetooth and mentions some uses within healthcare.

Bluetooth can be used as a way of connecting wearables and equipment to other devices. When equipment and people are Bluetooth-enabled, asset tracking and wayfinding become possible. Staff can quickly locate valuable hospital assets and patients in need for urgent care.

Another reason for using Bluetooth is reliability. The article mentions Bluetooth’s adaptive frequency hopping (AFH) that makes communication more reliable in noisy wireless environments. You can read more about the technical aspects in our post on Bluetooth LE on the Factory Floor.

A further reason for using Bluetooth, particularly Bluetooth LE, is low power. Stand-alone devices can work on coin-cell batteries for many years.

The final reason given for using Bluetooth is the ability to create larger site-wide networks using Bluetooth mesh. Mesh can be used for control, monitoring and automation systems without the need for WiFi that can be unreliable and congested in hospitals.

For a further look at usecases, see the post on RTLS in Healthcare.

UPS Shipping Update

We have been using UPS shipping for just over a month now and have just refined our shipping options based on past customer orders and our costs. UPS offer two main services, UPS Standard that goes by road and UPS Express that goes by air.

We have found that UPS Standard to some European countries is taking 5 to 6 business days which we can now improve on for some countries. For Italy, Spain, Austria, Finland, Greece, Denmark and Sweden we now always send by UPS Express (by air) for a similar cost as was the case for UPS Standard. This has a delivery time of 1 to 2 days to most business areas.

UPS Standard goes via the new London Hub that shows as ‘Stanford Le Hope, United Kingdom’ in the tracking. This is UPS’s largest single infrastructure investment outside of the United States. View the video:

The London Hub is 32,000-square metres in size and has a capacity to process up to 28,000 packages per hour. It’s part of UPS’s $2 billion infrastructure investment programme in Europe.

UPS Express gets to via East Midlands airport by the evening of the day it is picked up from us and shows as ‘Castle Donington, United Kingdom’ in the tracking.

UPS Freight Flight from East Midlands Airport/Castle Donington

Freight flights leave every evening to Europe and North America that are delivered in 1 to 2 working days to Europe and 2-3 days to N America.

View the shipping page for a summary of delivery costs and time scales.

INGICS Bluetooth Gateway MQTT Service Levels

The INGICS iGS01S (WiFi) and iGS02E (Ethernet) gateways support MQTT to send data to a server.

iGS01S Bluetooth LE WiFi Gateway

MQTT defines three levels of Quality of Service (QoS) that relate to whether requests are resent if not acknowledged:

  • 0 – The broker/client will deliver the message once, with no confirmation.
  • 1 – The broker/client will deliver the message at least once, with confirmation required.
  • 2 – The broker/client will deliver the message exactly once by using a four step handshake.

The INGICS gateways only support QoS level 0. This is because these gateways have lower memory and processing capability. They don’t have enough memory to queue unacknowledged requests required of other QoS levels. The extra processing would also significantly impact the performance and hence throughput.

If you need a higher MQTT service level then try the Minew G1 that supports QoS levels 0 and 1.

Lastest Issue of Wireless Q Available

Nordic, the manufacturer of the System on a Chip (SoC) in many beacons, has published the latest issue of Wireless Quarter Magazine. It showcases the many uses of Nordic SoCs.

This issue mentions three ‘smart’ products, a smart cricket ball, a smart luggage tag and a smart bike helmet that are effectively beacons or sensor beacons in different form factors.

The IoT will overtake smartphone centric products as Bluetooth LE tech’s main market by 2024

The World’s first dual Arm Cortex-M33 SoC, the new nRF5340 SoC, is also mentioned. This will allow for more CPU intensive applications such as TCP/IP networking and edge processing of data.

There’s also a feature on asset tracking and locating systems valued at $19 billion last year and expected to reach $128.75 billion by 2027, with a Annual Growth Rate (CAGR) of 24.5%.

The Sogo/MokoSmart VILOG car tracking system is featured and is pertinent as we are a distributor for MokoSmart beacons.

Comparison of Bluetooth LE Locating Methods

There’s research just published on A Comparison Analysis of BLE-Based Algorithms for Localization in Industrial Environments. The research compares trilateration, fingerprinting and a machine-learning based k-nearest neighbors regressor for determining the location from signals from multiple beacons.

Multi-layer perceptron (MLP) schematic model
Error box plots for the three fingerprinting algorithms with different beacon densities. Results for a fingerprint grid with one measurement every 0.5 m.

The results show fingerprinting is better than distance-based schemes in industrial environments due to the presence of large moving metal objects that shadow and reflect wireless signals. The three methods were found to provide similar localisation accuracy. The authors say the machine learning method is best due to less complexity and better adaptability. The machine learning method does not need regular calibration as is the case with fingerprinting.

Read about Determining Location Using Bluetooth Beacons

Low Power Bluetooth Advertising Chip Without SoC

Asahi Kasei Microdevices Corporation has announced the AK1595. As with the previously mentioned AK1594, it works without a System on a Chip and provides Bluetooth transmission using very low power.

Instead of setting the advertising via EEPROM programming like the AK1594, the AK1595 is controlled via UART or I2C making it suitable for variable data transmission scenarios.

We expect the AK1595 will be particularly useful for energy harvested applications.

Sensor Triggered Advertising

Most of our sensor beacons with accelerometers offer motion triggered broadcast. That is, they can be set up to advertise when the beacon is moving. This can be used for motion detection or, in some scenarios, as a mechanism to significantly conserve battery life.

Some beacons such as the Minew range with buttons can be set to only advertise when there’s a double press of the button. This can be used for SOS type scenarios.

The S1 temperature humidity beacons can also be set to advertise when the temperature or humidity goes above or below a value. This is useful for alarm type situations.

S1 Beacon

While triggered broadcast provides for these usecases and extends battery life, it should be remembered that because the beacons are not advertising all the time, there’s no way of knowing their location (in RTLS situations) or indeed if the beacon is working (e.g. the battery might be flat). Beacons such as the INGICS range advertise all the time and send different advertising when a button is pressed or the temperature/humidity changes. This allows for ‘I am still here’ functionality at the expense of shorter battery life.