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In a project, I want to measure weight with the resolution of 1 gram. Things I want to weigh, are max of 6 grams and I need to diffrentiate between a 5 gram thing and a 6 gram thing.... So I would require a Load cell with resolution of 1 gram.

I searched in Local Market as well as online but I couldn't find a good one.... Can anybody have suggestions what can I do?? Or Links where such load cells are available will be way good....If anyone used such load cells then...then I would be the happiest person on earth! :)

Thanks!

P.S. I been to omega.com but these are very costly.... If no other alternative.... I have to choose them or close the project.... Second option would be easy for me! :(

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    \$\begingroup\$ have you considered finding a cheap gram scale and taking out the load cell out? usually I see them accurate down to +-.1 grams. \$\endgroup\$
    – jsolarski
    Commented Mar 29, 2011 at 11:08
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    \$\begingroup\$ @jsolarski - I guess display resolution is 0.1 grams; I seriously doubt that you get that kind of precision from a cheap kitchen scale. It's like digital fever thermometers. They usually display to 0.01 degree centigrade. That's not the precision, though. Not for a 10 euro thermometer anyway. \$\endgroup\$
    – stevenvh
    Commented Mar 29, 2011 at 17:24
  • \$\begingroup\$ @stevenh Accuracy depends greatly on the calibration of the circuit and how they measure the load cell. Yes a cheap load cell will have worse characteristics then a High quality one. This is why Scales are calibrated with standard Weights either at the factory or a built in function and I don't see why you couldn't get even Higher accuracy using a better ADC then one in the hacked scale. \$\endgroup\$
    – jsolarski
    Commented Mar 30, 2011 at 7:10
  • \$\begingroup\$ @jsolarski: it's an illusion to think you can get any precision you want just by calibrating. That would require all components to be perfectly linear, which isn't the case. Every system has its practical limitations which can't be fixed with calibration. \$\endgroup\$
    – Federico Russo
    Commented Apr 24, 2012 at 8:03

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have you considered finding a cheap gram scale and taking out the load cell out? usually I see them accurate down to +-.1 grams

As stevenh pointed out, cheap scales may not be that accurate, compared to there "box values" If you are just using a load cell from it you should be able to get at least the same and or better accuracy if you have a sufficient design for your ADC and cell combo. To get even better results i would suggest getting a small set of standard weights to calibrate your device.

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    \$\begingroup\$ Instead of Buying a Gram scale, I went to it's service station and enquired about the internal circuits and from where they get these load cells.... Fortunately those guys were enthusiastic and gave me lots of info!! Thanks @jsolarski for this idea! \$\endgroup\$
    – Swanand
    Commented Apr 5, 2011 at 8:57
  • \$\begingroup\$ Care to share that information? \$\endgroup\$
    – user4385
    Commented May 24, 2011 at 4:46
  • \$\begingroup\$ what information are you looking for? \$\endgroup\$
    – jsolarski
    Commented May 25, 2011 at 1:37

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