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You want a digital scale for What??
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jh15:
I would like a discrete scale you could use at a restaurant.
     Is it cheaper by the cup or bowl for example.
     A flat load cell/platform that wouldn't be noticeable.
Somehow a readout with tare after food is consumed. These days to your phone, but any readout is good for me.
     Been thinking decades ago of using a strain gauge, but recently adapting these mini scales.
    There. Now someone start a kickstarter.
Also to be fancy, could automatically go to a spreadsheet to figure cost per weight of steak at restaurant A compared to B, etc.
     
ace1903:
I looked for long time for precise measurement of NaOH that I am using as a developer for Positiv20 spray.
Found device that audiophiles use for turntable evaluation.

Does anyone know if this device can be reused for measuring small quantities in chemistry?
https://www.amazon.com/Cuiedailqhb-Portable-Digital-Turntable-Tracking/dp/B0832ZV5KR?th=1

Anyone that made tear-down or knows measurement principle used in that device? S shaped aluminium with resistive sensors is very unlikely to be used. 
jfiresto:
That is only a 500 count scale which probably keeps the cost down. You might ponder a scale's uses and aim for one that is a little more ambitious if you think it might have other uses.

Commercial and even consumer scales typically do better, offering 3000 and 1000 counts, respectively. Good industrial and laboratory scales can routinely manage two to three orders of magnitude better, with a lab scale offering half a million useful counts of resolution being nothing extraordinary.
jogri:

--- Quote from: ace1903 on September 17, 2020, 11:46:59 am ---I looked for long time for precise measurement of NaOH that I am using as a developer for Positiv20 spray.
Found device that audiophiles use for turntable evaluation.

Does anyone know if this device can be reused for measuring small quantities in chemistry?
https://www.amazon.com/Cuiedailqhb-Portable-Digital-Turntable-Tracking/dp/B0832ZV5KR?th=1

Anyone that made tear-down or knows measurement principle used in that device? S shaped aluminium with resistive sensors is very unlikely to be used.

--- End quote ---

Protip from a guy that has done that: Never try to weigh your NaOH if you want accurate measurements, that stuff is highly hygroscopic and trying to measure it accurately is a royal PITA as you have to remove the crust of every single pellet you are going to use as the crust mostly consists of water, screwing over your calculations... Oh, and it also collects the CO2 in the air to form sodium carbonate, and you won't get that stuff off by simply heating it.

If you want to make a solution with a known concentration you have two options:
-Make the solution and measure the concentration by a titration (can be done at home, but takes a bit of experience). Keep in mind that you will have a bit of sodium carbonate in it, so not a good idea if something is sensitive against that stuff
-Wash your NaOH before you use it: Take a bit of water, rinse the pellets/nuggets and dump that water, then heat it in a drying oven (but not for too long as it will start to collect CO2 from the air), then weigh your dry NaOH and add the required amount of DI water. Not as precise as doing a titration, but more than good enough for most applications
ace1903:
Usually I buy ecofriendly developer for photoresist that only needs to be diluted with 1l distilled water.
But due to problems with shipping I switched back to local supplier for chemicals.
Fortunately I don't need extremely precise measurement since process is tolerant to range of concentrations.
7g is at low side on those 200g range 0.01g resolution scales and I don't want to keep several liters of NaOH.

Could you please provide info what is used to titrate NaOH? I already have set of lab glassware and maybe 30 chemicals.

I hoped that this 5g scale will have better resolution since I am close to max range. But I didn't notice this 500 counts limit.
Is this resolution limit of the measurement principle or I can override it with some 16bit ADC and nucleo board that I have on disposal?


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