Battery-free LoRaWAN sensor

HarvyLR: compact, self-powered, maintenance-free

HarvyLR is a LoRaWAN sensor for aquisiton of DC and AC currents. Unlike common LoRaWAN current sensors, it does not require any battery or external power supply. Once installed, it runs self-sufficient and maintenance-free: the IoT sensor draws the energy it needs for operation from its environment. The principle behind it: Energy Harvesting.

The sensor can digitize both common analogue signals of 4–20 mA and alternating currents of up to 36 or 360 mA. A typical application is the aquisiton of RMS currents at electrical main or sub-distributions or directly at the plant. For this purpose, it is simply combined with a suitable deZem clamp-on current transformer.

An intelligent event filter is integrated into the current sensor, which, for example, maps the inrush currents of systems to the second. Alternatively, measured values can also be read out in a fixed time grid – even synchronously for measuring points distributed anywhere in the world.

The sensor is available in two variants:

HarvyLR-36: for AC currents up to 36 mA (with deZem clamp-on current transformers W15, W80/T80 as well as W150, provided load is normally below 100 A) and 4–20 mA DC analogue signals

HarvyLR-360: for AC currents up to 360 mA (with deZem clamp-on current transformers W300/T300, W500/T500)

Why HarvyLR?

  • For any AC or DC current signal up to 36 or 360 mA respectively
  • Self-powered and maintenance-free (battery-free!); input current of 0.125 mA is sufficient for stable operation (with HarvyLR-36)
  • AC and DC signals can even be combined if, for example, a fixed supply is required
  • Tests confirm excellent data transmission over several kilometers and through thick house walls
  • With intelligent event filter, which enables measurement series (inrush currents, etc.) accurate to the second, at a fixed maximum rate
  • Compact design
  • Easy installation; no cable pulling
  • Configuration and updates via Bluetooth
  • Applicable with the deZem IoT platform and any other platform (JavaScript decoder freely available, e.g. for the TTN)

Example of application

  • Wireless reading of widely distributed and inaccessible sensors of various types, such as in factory buildings, building complexes, or outdoor sites
  • Readout of sensors with mA output that are powered by movement from wind, water or light, e.g. illuminance via PV cells, anemometers with current output, flow sensors with direct current output
  • Connecting ultrasonic flow sensors (4–20mA output), which are often installed in locations without good data connectivity

Simple measurement setup

  • e.g. connect a 4-20 mA analogue signal or deZem clamp-on current transformer via plug-in contact with suitable HarvyLR
  • HarvyLR sends encrypted measured values to LoRaWAN gateway
  • LoRaWAN gateway sends measured values via LTE router or existing network connection to an IoT platform, e.g. the secure deZem IoT platform