Modern sensor technology at the historic Ettl Mill

In order to meet these complex requirements, Thomas-Krenn and CONNCTD decided to use LoRa (Long Range) nodes with suitable sensors as well as a gateway optimized for these applications. The distances involved were no problem for the long-range LoRa technology. All measured values are transmitted via LoRaWAN radio technology to the CONNCTD cloud, where they are decoded, evaluated, visualized and processed with history and alarm functions. For the level measurement at the weir, the decision was made in favor of an ultrasonic sensor with a long-life battery. This was fixed directly to the weir by means of beam clamps and monitors the position of the water surface from here in real time. The measuring point at the fish ladder, however, required a different approach. Here, a sensitive submersible pressure probe made of ceramic was used. Its data is transmitted via the ModBus RS485 interface. The sensitive supply cable of the probe is protected from beaver bites and other damaging external influences (such as mud or debris deposits) by a robust pipe. To counter the threat of flooding, the company AB Anton Bogner manufactured and installed special metal bracing to keep floodwaters, flotsam and other environmental influences away from the sensitive electronics. A lithium battery with active charge control and solar panel ensures self-sufficient operation of the node, which automatically goes back into an energy-saving deep sleep mode after each data transmission. Finally, the RED-certified low-power TK industrial LoRa IoT gateway forms the heart of the installation. The LoRa nodes communicate via NUC and a software-based Docker LoRaWAN/Linux server stack. After successful configuration of the gateway and the nodes, the data packets are pushed into the IoT cloud.