The Nordic blog has an informative post on How IoT-Based Predictive Maintenance Can Reduce Costs. It explains how connected sensors can save maintenance costs through reduced downtime. The post provides some examples from the power industry and explains how the same techniques can be used in the tools, retail, distribution and physical infrastructure industries.
As the post mentions, the challenge is how to scale this up. We are told IoT is the solution. Here at BeaconZone, we don’t believe IoT is always the solution, especially where there’s a requirement for higher sensor sampling frequencies. There’s too much data, too much data transfer and too much server processing. It really doesn’t scale. Apart from the waste and cost of these resources, the latency of triggering events based on the data is too high. Instead, look to so called ‘edge’ or ‘fog’ computing where more processing is done nearer the sensors and only pertinent data is sent to other systems.
Connected factory implementations require a large number of connected assets for condition-based monitoring, asset tracking, inventory (stock) management or for building automation. Bluetooth is a secure, low cost, low power and reliable solution suitable for use in connected factories. In this post, we examine the reasoning behind some out-of-date thinking on industrial wireless, uncover the real problems in factories and provide some explanations how Bluetooth overcomes these challenges.
Operations teams are usually very sceptical about industrial wireless. They have usually tried proprietary industry solutions using wireless with mixed results. They might have experienced how connections, such as WiFi, can become unreliable in the more electrically noisy areas of factories. The usual approach is to use cable. However, this can become expensive and time consuming. Using cable isn’t possible when assets are moving and becomes impractical when the number of connected items becomes large as in the case of connected factories. As we shall explain, Bluetooth is intrinsically more reliable than WiFi even through they share the same 2.4GHz frequency band.
There’s usually lots of electrical noise in an industrial environment that tends to be one of two types:
Electromagnetic radiation emitted by equipment. This typically includes engines, charging devices, frequency converters, power converters and welding. It also includes transmissions from other radio equipment such as DECT phones and mobile telephones.
Multipath propagation which is reflection of radio signals off, usually metallic, surfaces and received again slightly later.
It’s important to understand how Bluetooth and other competing technologies react to these types of interference. There’s a useful study (pdf) by Linköping University, Swedish Defence Research Agency (FOI) and the University of Gävle on noise industrial environments.
Noise in industrial environments tends to follow the following spectral pattern:
Electrical noise spectrum
There’s usually lots of electrical noise up to about 500MHz. This means wireless communication using lower frequencies, such as two way radio, exhibits a lot of noise. Pertinently, several wireless solutions for industrial applications use frequencies in the 30–80 MHz and 400–450 MHz bands. Bluetooth’s and WiFi’s 2.4GHz frequency is well above 500MHz so exhibits better reliability than some industrial wireless solutions. Incidentally, in the above charts, the peaks around 900 MHz and 1800 MHz mobile phone signals and 1880–1890 MHz come from DECT phones.
The magnitude of multipath propoagation depends on the environment. It’s greatest in buildings having highly reflective, usually metallic, floors, walls and roofs. If you imagine a radio signal wave being received and then received again nanoseconds later, you can imagine how both the amplitude (peaks) and the phase of the received signal becomes distorted over time. Bluetooth uses Adaptive Frequency Hopping (AFH) which means that packets transferred consecutively in time do not use the same frequency. Thus each packet acts like a single narrowband transmission and there’s less affect of one packet on the next one. However, what is more affected is amplitude which manifests itself as the received overall signal strength (RSSI). RSSI is often used by Bluetooth applications to infer distance from sender to receiver. We will mention mitigations for varying RSSI later.
It’s important to consider what happens when there is electrical noise. It turns out that technologies invented to ensure reliable transmission behave much less well in noisy situations. One such technique is carrier sense multiple access (CSMA), used by WLAN (WiFi), that listens to the channel before transmitting and waits until a free channel is observed. CSMA and automatic auto repeat (ARQ) also have re-transmission mechanisms. The retrying can also incur significant extra traffic that can overwhelm the communication in noisy environment. Bluetooth doesn’t use such schemes.
The previously mentioned research classifies different wireless technologies according to the delay when used in noisy environments:
Bluetooth (and WISA) is a good choice for noisier environments. It’s particularly suited for applications with lower data rates and sending at periodic intervals.
A final consideration is interference between Bluetooth and other technologies, such as WiFi, that use similar 2.4GHz frequencies. As mentioned in a previous post, there’s negligible overlap between Bluetooth and WiFi channel frequencies.
In summary, Bluetooth is more suited to electrically noisy environments and also offers low cost, low power and secure wireless communication.
These conclusions correlate well with our own empirical observations. We have found that Bluetooth advertising is still received in environments we have measured, using a RF spectrum analyser, to be electrically noisy around 2.4GHz . We believe this is because Bluetooth advertising hops across three frequencies such that there’s less likelihood of noise on all three. Advertising is also very short, typically taking 1 or 2 ms, making the coincidence of the noise and the advertising less likely than would be the case of a longer transmission.
It has been our experience that solutions using Bluetooth advertising are more reliable than those using Bluetooth (GATT) connections, especially in noisy environments when it’s difficult to maintain the chatty protocol of a connection over a long time period. In noisy situations, advertising is usually seen on a future transmit/scan if the first advertising is lost. By coincidence or design, Bluetooth Mesh is built on communication via advertising rather than connection and for this reason is also reliable on the factory floor.
However, using Bluetooth isn’t a silver bullet. There are situations where factories, or more usually parts of factories, have reflective surfaces or unusual radio frequency (RF) characteristics stretching into unforeseen frequencies. Poorer performing WiFi also needs to be considered in context of choosing between Ethernet and WiFi gateways and Bluetooth mesh.
It’s important to do a site survey including RF spectral analysis. This will uncover nuances of particular critical locations or coverage that can drive subsequent hardware planning. It can also feed into requirements for software processing, for example particular settings for processing within a real time locating system (RTLS) to cater for more varying RSSI.
The 4th Industrial Revolution (4IR), also known as Industry 4.0, is the use of technology to improve operational efficiency, increase throughput, minimise downtime, improve quality and lower costs. We have an article that explains how beacons are part of 4IR.
There’s a lot more to 4IR than tracking items and analysing data. It also includes areas such as automation, robotics, cyber security and 3D printing. There’s a free online Industry 4.0 Magazine that can help you get up to speed.
We now have the INGICS iGS02E Bluetooth to Ethernet gateway (without PoE) in stock.
This small device looks for Bluetooth LE devices and sends their advertising on to a server via TCP, HTTP(S) or MQTT including AWS IoT. If you use with sensor beacons, this provides a quick and easy way to provide for IoT sensing.
ABI Research predicts that there’s going to be an increase in beacon-enabled app shipments mainly due to retail and ambient intelligence:
So what is ambient intelligence? It’s a catch all term for the joining of the Internet of Things (IoT), big data, the connected home, wearables, smartphones, voice/image recognition and artificial intelligence through machine learning.
Sensor beacons enable the gathering of new data. New data not only measures physical things but, more importantly, provides a way of circumventing the problem of silo data in many large organisations. Silo data is data people/departments don’t want to share for fear of losing power or control. Today’s machine learning techniques also require data to be in a specific format and ‘clean’. Creating new data allows it to be more readily formatted and conditioned prior to saving.
This isn’t just about location data. It includes physical quantities such as smaller-scale movement (accelerometer), temperature, humidity, air pressure, light and magnetism (hall effect), proximity, heart rate and fall detection. Our conversations with beacon manufacturers tell us beacons are currently being developed that detect more nuanced quantities such as colour, gas and UV. Some beacons already have general purpose input/output (GPIO) such that custom beacons can can already detect anything for which there’s an electronic sensor.
So why Bluetooth beacons rather than other electronics with the same sensors? Here are the main reasons:
Integration without soldering or, in most cases, without custom electronics
Communication with iOS and Android apps and computers via existing Bluetooth APIs
Remote, low power, data acquisition where there’s no mains power and no connectivity at the place of measurement
Significantly lower cost compared to traditional industrial sensing
BeaconZone will be exhibiting at the Industry 4.0 Summit Expo in Manchester on 28th March and 1st of April. We will have our beacons on show and visitors can view our BeaconRTLS platform.
Learn about Digital Twins and how Bluetooth sensor beacons can be used to provide data to drive models of systems, mirroring real-time status to improve operational efficiency.
Oracle and the EEF have an excellent free, recent, paper (registration NOT required) on The 4th Industrial Revolution: A Primer for Manufacturers. It concludes 4IR isn’t hype and should be taken seriously. Here’s how manufacturers themselves see 4IR:
Manufacturing is undergoing a transformation. The report says it’s all about data connectivity. However, the report falls short on explaining how data can be sensed and captured. Sensor beacons, gateways and beacon platforms such as our BeaconRTLS are one such solution that helps fill that gap.
Mr Beacon has an interesting new interview with Sam Jha, Chief Business Officer of Alpha Ori. Alpha Ori work with the shipping industry that’s still lacking the productivity gains many other industries have experienced through the use of IT. While the interview talks about shipping, it’s equally applicable to all industries.
In the shipping industry, IoT can be used to measure ships’ systems. This can produce thousands of data points per second that can be analysed using ‘big data’ techniques. The key is to identify insights that have value in that they can impact the areas where there are large costs. An example is maintaining up time and using sensing to estimate the life remaining on machinery, detect when things are starting to fail and replace preventative maintenance with predictive and prescriptive maintenance. Better maintained ships can also have the side affect of reducing other costs. Smart ships have lower insurance risk profiles and can hence save insurance costs.
The key message is one of identifying areas where there are large costs and using IT to optimise those areas. In shipping or any industry this usually involves sensing on machinery and systems to maintain optimum up time. It also involves detecting when to perform in-time maintenance to get the maximum life from expensive machinery. Beacons, particularly sensor beacons, provide the sensing part and are especially suitable for areas that don’t have power, lack cabling or are difficult to monitor manually due to accessibility.
