LoRaWAN / NB-IoT soil moisture sensor with SMT50

general description

This combination of a LoRaWAN or NB-IoT transmitter and an SMT50 allows for accurate soil moisture measurements over long distances (LoRaWAN typical range in open air is approximately 1 km / NB-IoT via the cellular network). Using two or three SMT50s, moisture can also be measured at different soil depths.

The set comes completely pre-configured by us, and on request we can also adjust the cable lengths (standard length = 10m, shorter possible).

It includes 1x Dragino LoRaWAN / NB-IoT sensor and up to 3x SMT50 sensors.

Use of multiple sensors

Possible use: With the upper sensor, irrigation can be controlled depending on soil moisture and with the lower sensor, a termination condition can be set when the soil has reached a deep moisture level.

Read values

A) LB / NB-IoT Model (Battery Only)

• In the 1x SMT50 variant, temperature and soil moisture are read out
• In the 2x SMT50 variant, temperature is read from sensor 1 and soil moisture from sensors 1 and 2
• In the 3x SMT50 variant, only soil moisture sensors 1, 2 and 3 are read.

B) LS Model (Battery+Solar)

• In the 1x SMT50 variant, temperature and soil moisture are read out
• In the 2x SMT50 variant, soil moisture from sensors 1 and 2 is read
• Variant 3x not available because the 3rd analog connection is internally occupied by the solar module

In all variants the battery voltage is added

LoRaWAN Gateway

A corresponding recipient is required to collect the data. We distinguish between two categories:

a) Cloud-based data storage:

Here, the receiver (gateway) only serves as a forwarding instance, so the LoRa / LoRaWAN receives data and forwards it to a cloud service, e.g. ThingsIndustries

e.g. the Dragino MS20

b) Local server

With this variant, the data remains stored on the gateway and can be retrieved from there; MQTT is also directly available

e.g. the Dragino LPS8v2

NB-IoT

a) The mobile operator usually provides a platform for this purpose.

b) The sensor can use MQTT directly. Therefore, only an internet connection is required (via SIM card).

OpenSprinkler

For combination with OpenSprinkler All of the variants mentioned are possible, provided that the measurement data can be made available via MQTT.