08. September 2020
Transfer measured values from IoT devices without using the Internet
For over ten years now, KELLER Pressure has been producing remote transmission devices that use mobile phone networks to send measured values such as pressure or temperature to data stores on the Internet. In the early days, 2G, 3G and 4G technologies were used for this, with LPWAN transmission technologies such as NB-IoT and LTE-M since arriving on the market.
For the past three years, we have also provided the ARC1 and the new ADT1 LoRaWAN-compatible devices. LoRaWAN is an IoT network protocol based on chirp spread spectrum technology that can be used with compatible radio masts served by telecommunications companies to store data on the Internet. One of the many benefits of LoRaWAN is that this technology is very energy-efficient and thus allows operations to be conducted in a more affordable and environmentally friendly way. They operate in an unlicensed frequency band which means that everyone may build their own network. You do not require a SIM card and can purchase a «LoRaWAN gateway» to connect any number of remote transmitters to several pressure sensors!
Figure 1: LoRaWAN gateway with ChirpNest and loading and visualisation software «Kiwi Desktop» works offline
The gateway, which is connected to the Internet, receives the encrypted measurements from the LoRaWAN transmitters and forwards the data to the Internet where it is then stored. The KOLIBRI Cloud, which is optimised for pressure measurements and the resulting water levels or tank contents, can be used as a data store.
There are, however, situations where the Internet is not available at all or customers are not allowed or do not want to store data on the Internet.
Two students from the ZHAW Zurich University of Applied Sciences, including KELLER employee Lukas Raschle, addressed this problem in their Bachelor’s thesis – and managed to solve it!
The aim of the thesis was to develop a viable, customer-friendly and open solution that works without the Internet. Nevertheless, the benefits of the new IoT wireless technology should be made use of to collect and visualise data from many different LoRaWAN transmitters.
The result? The «ChirpNest» open source solution. It is freely accessible and documented on GitHub: https://github.com/ChirpNest/ChirpNest
ChirpNest provides similar features to the KOLIBRI Cloud, but in a reduced form. The idea here is to use a special gateway, i.e. LORIX One, and combine the following characteristics in the device:
- Gateway with antenna
- LoRaWAN network server with management function devices
- Data store
- LAN interfaces to connect the device to a local network or notebook
The installation is designed in as simple a manner as possible so that the user can manage without help from KELLER. Instructions are, of course, also available.
All you need is a «LORIX One» gateway, an SD card containing a ChirpNest image and a random number of LoRaWAN devices from KELLER.
The data collected on «LORIX One» can be read as often as required and exported in different formats. All you have to do is connect your computer to «LORIX One» using the network cable and select the desired data. The formats are available as Excel, CSV and also in KOLIBRI formats so they can be imported to the «KOLIBRI Desktop» if required.