Arduino simple modular IoT


I would like to ask you about your experiences with some Arduino simple and modular IoT. Is there any simple, easy to use and modular Arduino system which would create IoT in home and garden?

I mean, is there any ready to use project which really simplify building of IoT at home? Something like a plug and play network where you can just add new devices which will start to comunicate, send data and receive data from the cloud or from some application? Do you have any experience with such project?

I am interested especially in the network which would be remotely connected via GSM. It should be cheap but reliable. Currently it would be used for remote garden system.

The important features should be:
Secure communication
Wireless connection
Low power consumption
Simple and reliable communication protocol
Low cost and easi to build and extend
Modularity of the system which enable connection of GSM, wifi, 433 MHz modules etc.
Web interface
Perfect would be also feature to upgrade firmware of main nodes on the network but this feature is not required

Any advices will be appreciated.

I already developed similar solution with GPS and nrf modul. Low power consumption was done by sleep mode of nodes and GSM modul on only once per 30 minutes for data sending and receiving from MySql database. There was also simple web interface for sending command for nodes or settings on nodes. The system is also described on but only in Czech language. Files are available for download.

Now I am looking for similar solution but more robust and secure. Or would be somebody interested in such developement? I would be ready for such developement but only if more people would work on it as it would require enough time to develope it.

Would be somebody interested in it or does anybody know about some ready to use solution?

Thank you in advance.

I mean, is there any ready to use project which really simplify building of IoT at home?

There probably is, but it has nothing to do with Arduino or this forum.
Meanwhile, there are plenty of examples of Arduino monitoring using IoT around here, I believe the current weapon of choice is Blynk, but plug and play is a but of a stretch, and some intellectual input is usually required. That input can be rewarded with the "cheapness" you also demand. Don't expect to get it by other means.