I've set up my hacked IM-403 cash register computer as an automatic data collection system. The system sits on my workbench, reading several different sensors on a set schedule and writing the data to a file. Periodically, the system dials into my ISP and uploads the latest data to my web page, then hangs up and resumes collectiing data. If you're looking for a data collection system that is web-aware, costs next to nothing to build, and runs on a 486 (or less) DOS box, check this out!
Once you have the IM-403 (or similar DOS box) running, the rest of this system is primarily software. You need three major software elements, two of which are available on the web:
1. cron version 1.9, a task scheduler
2. fnos version 1.7b, an FTP system
3. Some kind of dedicated program for reading your sensors and framing the data as you want it for transfer to your web page (you get to write this part!)
You'll also need a modem. I'm using a Zoom V34X+ external 33K modem, hooked to COM3.
After you get all the pieces together, just create an entry in your crontab file that calls your data collection program whenever you want to run it. Also add an entry that invokes fnos with the proper script file whenever you want to update your web page. Then run cron with the -v option. The console will show the countdown before each task is run, and the actual running of each task at the assigned time.