Cellular IoT irrigation sensor detects water leaks and tracks agricultural sprinkler carts

Norwegian company 7Sense has launched a cellular IoT irrigation sensor capable of water leak detection and location monitoring for sprinkler carts. The ‘7Sense Irrigation Sensor Gen III’ is designed for use on farms, and can be easily retrofitted to almost any type of legacy irrigation system. Alerts and notifications about water leaks, the sprinkler’s location, speed and estimated finish time are transmitted to the Cloud via Nordic’s nRF9160 low power SiP’s multimode LTE-M/NB-IoT modem. From there, the information can be sent to the farmer’s smartphone for viewing on the ‘7Sense’ app.

“Using our patent-pending, non-intrusive flow detection, the device can immediately sense any loss of water and alert the farmer,” says Max J. Tangen, CEO of 7Sense Agritech. “This not only reduces water waste, but also means that manual resources can be reallocated from monitoring irrigation systems to more productive tasks.”

Analyzing micro vibrations

The nRF9160’s powerful 64 MHz Arm® Cortex®-M33 application processor provides the necessary computational power for the sensor to monitor and analyze the micro vibrations in the water pipe. Changes in these vibrations indicate a change in flow and potential leak.

Using a combination of cellular network location data and GNSS and 7Sense’s proprietary Cloud service, the device also provides precise position monitoring for sprinkler carts. This enables farmers to be notified when carts pass certain points, or let them know if a cart has overturned or stopped moving. Additionally, the 7Sense Irrigation Sensor Gen III can send updates about when the sprinkler carts are expected to finish the irrigation cycle. 

From the app (available for iOS and Android) users can access an overview of the irrigation process, including real-time information such a sprinkler location and progress, historical data, fleet asset management and a map view of irrigation routes. 

Two-year battery life 

Using a lithium primary battery cell, the irrigation sensor can function for up to two years between battery replacements, thanks, in part, to the class-leading low power consumption of the nRF9160 SiP, which supports both PSM and eDRX power saving modes. For both LTE-M and NB-IoT the PSM floor current is as low as 2.7 µA, and with an eDRX interval of 655 s the average current is 6 µA for LTE-M and 9 µA for NB-IoT.

“This low power consumption was a major drawcard for the nRF9160 SiP,” says Tangen. “Alongside the powerful application processor and generous Flash and RAM for leak detection calculations. 

“Nordic’s SDK [Software Development Kit] helped us speed up the development of our application code and reach the market faster. This was one of the key reasons we chose to work with Nordic, along with the completeness of the SoC and the fast responses from skilled application engineers.”

• About 7Sense
• About nRF9160
• About Nordic Semiconductor