LoRaWAN / NB-IoT soil moisture sensor with SMT50

General description

New! With the SN50v3-LB / LB projects on Github there are now new possibilities. With the help of an ADS1115 chip on the I2C of the sensor, another 4 analog inputs are now available!

This combination of LoRaWAN or NB-IoT transmitter and SMT50 allows precise measurement of soil moisture over long distances (LoRaWAN typical range outdoors approx. 1km / NB-Iot via the mobile network). With two or three SMT50, the moisture can also be measured at different soil depths.

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

It includes 1x Dragino LoRaWAN / NB-IoT sensor and up to 4x SMT50 sensors.

Use multiple sensors

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

Read values

There are 6 analog inputs available, 4x on the ADS1115, 2x via the onboard inputs.

You define the configuration of the 6 inputs yourself. I recommend concentrating on the soil moisture and reading the temperature at the remaining inputs.

• With up to 3x SMT50, all soil moisture and temperature can be read out
• With 4x SMT50, 4x soil moisture and 2x temperature can be read
• We cannot recommend more than 4x SMT50, otherwise the battery will be drained.

In all variants the battery voltage is added

Gateway LoRaWAN

A corresponding receiver is required to record the data. We differentiate 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 accessed from there; MQTT is also directly available

e.g. the Dragino LPS8v2

NB-IoT

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

b) The sensor can directly use MQTT. This means that only one connection to the Internet is necessary (via SIM)

OpenSprinkler

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

Firmware adjustments OpenSource on Github:

https://github.com/OpenSprinklerShop/SN50V3-LB-ADS