Finding a sensor for measuring small weights with high accuracy.

Hello people.

I am not pursuing any formal education into electronics and components but I am looking for a sensor to be used in my next college project. I am feeling difficulty to find a particular type of load cell that weighs in grams and having accuracy up to 3 decimals in milligrams. My measurements will be ranging from 01.000 to 500.000 grams. Also, the sensor should be compatible with Arduino Uno/ nano

The sensor will be used to weigh small sample of milk and water and output will be connected to Arduino for analysis and calculations.

If anyone have came across any sensor meeting these specification, please tell me the name and number of that sensor.
TY! :smiley: :slight_smile:

Have you tried to hack a jewelry scale?

Does it have to be cheap?

There are many lab grade milligram balances with serial outputs. Expect to pay ~ $1000+.

It doesn't take long for a milligram of water to evaporate from an open container, or for a milligram of condensation to settle on the outside of a chilled container.
Is this for balancing a centrifuge?
Do you really need 1 part in 500000 resolution?

Ashish_Sahuji:
I am feeling difficulty to find a particular type of load cell that weighs in grams and having accuracy up to 3 decimals in milligrams. My measurements will be ranging from 01.000 to 500.000 grams. Also, the sensor should be compatible with Arduino Uno/ nano

If anyone have came across any sensor meeting these specification, please tell me the name and number of that sensor.

That one would probably fit.

https://www.amazon.de/DF-Digital-digital-interface-Digital/dp/B01F1RE2KK/ref=sr_1_fkmr0_2?ie=UTF8&qid=1501753966&sr=8-2-fkmr0&keywords=digital+pocket+scale+interface

A 24 bit resolution should be close to your requirements.
The range is 0..1000g, but with a simple lever, you may get into your specs.

But anyhow I wish you a LOT of luck with the corresponding mechanics to fit into your precision requirements!

Ashish_Sahuji:
Hello people.

I am not pursuing any formal education into electronics and components but I am looking for a sensor to be used in my next college project. I am feeling difficulty to find a particular type of load cell that weighs in grams and having accuracy up to 3 decimals in milligrams. My measurements will be ranging from 01.000 to 500.000 grams. Also, the sensor should be compatible with Arduino Uno/ nano

That kind of accuracy is very expensive. Or did you mean precision rather than accuracy?

For 6 digit accuracy in a set of scales you'll have to calibrate for the strength of local gravity which varies by
a fraction of a percent depending on latitude, altitude and geology.

Precision is more likely to be possible, but I suspect 4 or 5 digits is the practical limit without
expensive components, for instance this is only 5 digits: https://www.mkscales.co.uk/home/1672-bt-449-precision-balance.html

For 6 digits of precision this is the kind of price you pay:
https://www.mkscales.co.uk/laboratory-balances/1754-analytical-scales-ultra-120a-205a-series-with-internal-calibration.html
Note that it has to self-calibrate to keep the effect of temperature variations at bay...

That brings me back to my student time working in the labs :slight_smile:

We had such scales.
Must close the windows as your breath is more than enough wind to upset the measurement.
Usually installed in special tables with big granite blocks on rubber patches to stop vibrations from people walking on the concrete floor from reaching the scale.
All of them came with built-in self-calibration weights.

I don't know if they had serial interface. Maybe, maybe not. We'd normally just write down the weight.