The sensors form a network with each other. A Master sensor, acts as their gateway, collecting all the sensor readings and pushes them to the Internet using cellular connectivity. Below are the 2 types of sensors:
The master sensor acts as the gateway of your farm. It uses a SIM card to connect to the Internet. A typical installation requires only one master.
The node sensor has similar functionality with the Master, but instead of pushing data directly to the Internet, it can only be used in conjunction with a Master, acting as its gateway.
Clusters of sensors
A cluster of Node sensors uses one Master to push data out of the Farm/Greenhouse. Many clusters like this can be deployed, sending data as one farm. Many farms can be added under each account.