Just one question:
Do you need one single unit to access several sensors, and then communicate with a PC over wireless LAN?
If you are planning to design something yourself, I would suggest search google for wireless USB modules. And purchase one or 2.
Buy a couple of FTDI 245, USB modules (from
https://www.mouser.com/) for your fire detection you can use comparators and connect the output of the comparator to one of the i/o pins of the USB module. You can have up to 8 modules without any problem.
Then, you use the SW and the driver that is freely available from FTDI, and write a small program in C or VB on top of that and you are ready to go.
I am not sure of your professor will accept this as a project for the 4th year (I would deffinitly not do so), but this can give you an idea how you can do it.
Even easier, if you do not want to do any HW job, then buy a labjack USB module
https://www.labjack.com/ connect it to the wireless USB and write your own code to capture the data and handle the informaiton, it is a quick and dirty solution.
I am nost if I was so helpfull, but just some crazy ideas,
BR,
/Farhad