What IoT devices would you recommend for MQTT experiments? Further recommendations on Smart home devices or simulators for security-related MQTT experiments will also be appreciated.
I would recommend to start from Raspberry Pi, the most popular. The Pi is definitely one of the easiest ways to get started with IoT and to build different prototypes. But for anything more serious like commercial or industrial products Pi is not the best choice.
I recommend to read the book "Building the Web of Things" with good example of implementation simple IoT system on Rasp Pi from A to Z, from hardware connection to user application accessed through the cloud.
You can configure your device with MQTT or CoAP (Chapter 7 in the book) and test security using Kali Linux toolkit or something else.
Thank you very much for the information Ievgeniia Kuzminykh ! Highly appreciate it! Could you recommend specific smart home devices for security-related MQTT experiments, such as cameras, switches, access routers etc? If you could also recommend commercial devices for simulating traffic management I will be very grateful.