How to set up an IoT network to get associated data from the sensor to the Cloud? – part I

Thomas Steen Halkier – CEO of NeoCortec, and Zoltan Kiss – Head of R&D at Endrich Bauelemente Vertriebs

In this paper we are going to discuss the different possibilities to collect sensor data and get them into the Cloud using the E-IoT ecosystem. One way for data transfer is using smart sensors directly connected to the Internet, but there are many cases where a local wireless network of sensors with a single Internet gateway is a better and a more economical solution. We will discuss these options illustrated by the E-IoT ecosystem, which offers cellular LPWAN connectivity for direct sensor-database communication and has recently been using NeoCortec’s revolutionary NeoMesh protocol for having an ad-hoc, real low power, sub-GHz mesh WLAN to collect data locally and gateway it to the Internet from a single access point.

What is the E-IoT ecosystem?

Industry 4.0 expects machines and equipment to be connected, to exchange and use data collected by sensors. MCU based electronics take care of controlling the sensors, even offering the possibility to edge-compute the data and transfer it to a database for analysis or visualization. The ecosystem, that makes it all possible, is called IoT or Internet of Things. It contains hardware elements and software services such as databases and visualization tools. Endrich’s own E-IoT system is one of the possible choices, offering all that from one hand. Several IoT nodes, smart sensors, gateway devices as well as Cloud services are there for our partners to start their IoT development.

Endrich works in three major areas, where the first one is about converting conventional devices into smart. For that purpose, a RISC-V based general IoT Single Board Computer has been developed under open hardware and software structure; all technical data is freely available for the engineers on the market. The device is made as an engineering evaluation board to establish connection and carry out tests with the whole E-IoT platform. This can be a basis of more specific product development, and the slogan of the project is "We make your device smart".

The second area is to also involve other SBCs available in the market such as Arduino or Raspberry Pi, where Endrich offers extension shields to convert these MCU boards to full IoT endpoints by adding sensors and communication possibilities, so we simply "Make your SBC IoT ready". To also guarantee a better environment for people, Endrich calls IoT for help in environmental parameter monitoring under the motto "We care about the environment".

What sensor network architecture can be used to best serve the above tasks?

There are two major directions that IoT solution engineers may choose: having a smart sensor with own connection to the WAN (point-to-point or sensor-to-cloud solution) or using a local network of sensors and have a dedicated access point for this LAN to gateway the data to WAN. The E-IoT platform started with direct sensor-to-cloud communication, our classical sensor nodes had integrated LPWAN access using NB-IoT, and LTE-M modems.

We can use this as a powerful solution in cases when the sensors are in close proximity, such as in machines. The E-IoT family offers a great selection of proofs of concept to derivate into customer specific products. One of the most compact and versatile devices is the Mini E-IoT board with integrated LPWA modem, sensors, an external sensor interface and a wireless recharging circuit for the accumulator.

There are however cases when these devices offer limited services. Especially when you need a more frequent communication from many detection devices in a few tens or hundreds of meters distance from each other, the point-to-point solution is both too expensive and not sustainable from battery-lifetime point of view. In this case it is smarter to use a real low-power wireless communication protocol running on a mesh sensor network, offering a reliable, cheap, and sustainable way of collecting the data from the environment. A single gateway offers an exit to the WAN.

From technical point of view best cases to use a point-to-point solution appear, when the number of sensors is limited in number, they are close together, the frequency of data sending is relatively low and can be supported even by a battery for a long time, or when mains power is available to supply the node. In all other cases it is better to use the multipoint-to-point solution.

From economical point of view there are advantages of the point-to-point solution in case of single nodes. Of course, there is an additional telecommunication cost for using the cellular network, but due to the low data volume and the relatively rare connection, a prepaid IoT SIM card offers a significantly lower cost compared to legacy GSM services.

What kind of local network is suitable for smart sensors?

The ideal networking architecture is a mesh topology to be able to cover a large area compared to the distance of neighbor nodes. As the network should be operating on a battery, we cannot afford to have highly draining network coordinators and segment routers. Ideally all nodes should take care of their own sensors and the routing of neighbors’ data over the mesh. The higher the distance between neighboring nodes and the higher the number of nodes in the network, the higher the covered area will be.

This is helped by using sub-gigahertz radio communication, which also offers more reliable solution in harsh industrial environments due to the better (indoor) penetration. The networks should be easily extendable, and an ad-hoc installation should be self-explanatory. Reliability and data security are key factors in any kind of connected sensor systems, so the desired wireless solution needs to be cable-like reliable and the used security measures must offer a way to keep out eavesdropping and attacks. Finally, the used technology should be affordable, royalty-free and approvals (FCC, CE-RED) should be possible to get easily. For this reason, the developers of Endrich’s E-IoT ecosystem have chosen NeoMesh to be the right protocol running on the local smart sensor network.

To be continued in the next issue.

www.endrich.com