Hey Guys,
I did something very similar last year, and am building a second one now. We have an industrial scale that has a barcode reader attached, and an RS-232 output. I have it hooked up to a raspberry pi.
The use places an item on the scale, then scans the work order number of the item. The scale then outputs the weight (with UoM) and work order number. The Pi is standing by monitoring the serial port. When it receives the data it parses it to make sure the UoM is correct. It then sends that data to an internal web server. The web server uses the work order number to look up the stock code of the item, then records the date, weight, work order, and stock code into a database. It then checks the recorded weight against a table of predefined weights for the lower weight threshold, upper weight threshold, and the Not to Exceed Weight.
If the weight is between the threshold values the web server sends a back an Ok response along with the stock code, and then a green light flashes to let the operator know everything is ok. If the recorded weight is outside of the threshold values or is higher than the Not to Exceed Weight, three red lights flash, and the particular error message is displayed to the user on a 20x4 LCD screen. The user then has to push a button on the box to acknowledge the error and continue weighing items.
The reason I'm using a Raspberry Pi rather than an Arduino or similar is because it required network access.
I have the code (in Python) on GitHub. This was my first ever experience with Python so it may be a little messy. The code can be found at
https://github.com/cverburgh/PythonScale.
For recording your data, I would recommend using a comma delimited text file. It's plain text so it's easy to read and write to, and Excel will open it just fine.