Thanks Skimask for a quick reply. I have some experience with Proton picbasic. The data logger will be taking every 1s-10s samplings adjustable from Excel. What do you think the best way to make 20 minutes Clock? I've never used USB before but it might be a good idea to learn it. How to communicate between USB and excel? Would it not require custom PC software? Using serial port I can even use HyperTerminal to import the data.
I'd like to keep data logger very simple without external parts. This is just a hobby project and I know once my friends would see the data logger I would have to make them as well. I'd prefer to keep the project with minimum parts so I wouldn't even need a PCB and it'll be easy to build it for my friends.