Hi,
million ideas. Did you do an internet search? There must be a huge ammount of applications.
I guess we can´t help much, mainly just give the same recommendations that can be found in the internet already.
One point is that you don´t give much information.
IOT is such a wide range. I recommend to limit it somehow. Give a target..
Project, can be a theoretical study, a hardware , a software a complete network..You should at least tell what area you want.
Often there is arduino hardware involved, or the ESPxxx hardware...ory anything else. Give your idea.
What internet access? wired, wireless? internet pages (HTML) on your project or on a remote server?
Analog measurement, digital measurement, control loops, camera systems, speech recognition....tell us your ideas.
And why do you want to do this? For your own usage, for a school project...
Cost, timeline, ...?
Klaus