How to hack a weighing scale.

[Brumby]

You might have to be patient.  I have an urgent job at hand that is going to keep me busy for several days, at which time some other jobs are going to start getting short on time.

But hang in there.

[Nexo]

I will mate! Thanks in advance!

[bson]

Just buy a cheap USB scale.  I bought a Radio Shack one about 10 years ago (or more) that connected as a USB HID device, then connected to it and reverse engineered what it sent.  Super simple stuff.  These days I'd use something like https://freeusbanalyzer.com/ with any inexpensive USB scale, reverse engineer it and go write my own software for it.  (The free version of that one is session duration limited; I have the $200 pay version since that's the only pay version that will show raw data, which is 90% of my use.  There are many others also, but they all work and cost pretty much the same.)

[Smokey]

How is it we are on the second page here and I'm the first person to bring up the fact that this dude sure sounds like a student looking to get some class project done for him by someone else on the internet without making any effort to understand anything related to the job at hand or do any technical work himself?

[Nexo]

Well you are completely wrong.
First of all, if you read my previous treads, I'm a first year, second semester, student of EE and the subject that I asked here is studied at least in the third year so your point there makes no sense.
Second of all, I asked because I'd like to implement that on a personal project which I will most certainly not rate nor gain money from.
And third of all, wouldn't be nicer if you asked first what was it for instead of making assumptions based on what you think instead of facts?

Some people need a doze of common sense...

You just commented once in this thread and it was not helpful at all, wouldn't be easier for you just to stay out of this if you can't add value to the thread?

Have a good day, pal.

[cverburgh]

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.

[Smokey]

The only way you could have made your request sound MORE like a class project would be to start the post off with:
"Lab 4 - Data acquisition with Labview"

Once you get the data (from Labview?!?) is the next requirement to analyze it with Matlab? 

[ebastler]

How is it we are on the second page here and I'm the first person to bring up the fact that this dude sure sounds like a student looking to get some class project done for him by someone else on the internet without making any effort to understand anything related to the job at hand or do any technical work himself?

Maybe that is because you are the only one here who is a little paranoid in this respect?  ;-)

[Nexo]

The only way you could have made your request sound MORE like a class project would be to start the post off with:
"Lab 4 - Data acquisition with Labview"

Once you get the data (from Labview?!?) is the next requirement to analyze it with Matlab?

I'd like to teach you how to read... Why would you think that I want to analyze the data with Matlab if I said at the beginning that I want to create a Spredsheet :S

Dude, if you have nothing to contribute just keep rolling. Is sad to just comment things that aren't helpful.

[Smokey]

Labview and Matlab are equally crazy to use for a project like this, but it's the exact combination a university lab would have you use.  Throw in a little VHDL to code up your own processor to handle everything and now you are talking A+ type work!

[Nexo]

Labview and Matlab are equally crazy to use for a project like this, but it's the exact combination a university lab would have you use.  Throw in a little VHDL to code up your own processor to handle everything and now you are talking A+ type work!

In 3 years, when I study that software I'll come back and read your comment. Meanwhile, keep rolling [emoji4]

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