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Author Topic: Cannot find Affordable Precise Milligram Load Cell !! Help!!  (Read 912 times)
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Hello friends, I am new here.

I am an Undergraduate at USF and building a device which helps patients adhere to their medication for a term project.

In order to undertake this project, I must interface with a load cell that is precise (+- 5-10 mg - total weight range of 20g or so should be fine, operating at 5v preferably).

The problem is....these load cells don't seem to exist! The closest ones I have found are industrial strength and cost 100s - 1000s of dollars.

Is there anybody knowledgeable in this regard who could point me in the right direction or weigh in on the feasibility of finding such an affordable device?

I have looked on Digikey and Mouser (among many other medical device suppliers), and even sought the advice of a couple technical reps. No dice.

Please help!

Thank you for your time and consideration,
Tony
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Sorry I can't advise on any specific load cells, but bear in mind that it's possible to increase the load range or the resolution of the load cell by varying the mechanical leverage between the load cell and the item being weighed. What you really need is something with roughly the right sort of range (perhaps within a factor of ten) and the necessary resolution (which seems to be about 0.05% resolution over a given range).
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Tear open one of those cheap Chinese balances with 5 or 10 milligram resolution and see if you can interface to it somehow.
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Tear open one of those cheap Chinese balances with 5 or 10 milligram resolution and see if you can interface to it somehow.
I second that! I've had great luck with stuff bought here and the shipping is always free (but slow) http://dx.com/s/digital+scale
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Thank you all for your responses! Don't know how comfortable I feel about gutting a cheap scale, I would like to know the specifications of the load cell before purchasing and hoping its what I needed. Peter, I'm going to look into your suggestion. Again, thank you!
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Most digital balances with milligram resolution use magnetic restoring force as a sensor instead of strain gages.  I believe this is due to the drift in instrumentation amps.
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