New Digital Scale - Page 1
Forum section: electronics / general

author: vidarr
author_rank: Frequent Contributor
timestamp: April 26, 2021, 02:02:15 pm
content: I got a new kitchen scale and was going to calibrate and check accuracy against what I thought was a 3 gram weight.It has a 3 on the bottom and looks like something definitely made for scales, but it is not 3 grams, or 3 of anything,.It is 2.45 grams. Does anyone have any ideas what this thing is?

author: DrG
author_rank: Super Contributor
timestamp: April 26, 2021, 06:01:06 pm
content: No idea what that thing is. I am used to weight standards looking something like these:https://www.amazon.com/Hestya-Calibration-Digital-Balance-Tweezer/dp/B07B8J19DMBTW in the US, coins are actually not too bad as weight standards.https://sciencing.com/calibrate-scale-weights-4740563.htmlI found this out discriminating a certain date cent that could be either copper or copper plated...as long as they are not damaged, they are surprisingly within spec...at least to the degree that is usually acceptable in kitchen use - so long as you are not using LSD-25, or a similarly potent ingredientsNot sure about Brazil, but I bet it is a similar situation.https://www.bcb.gov.br/dinheirobrasileiro/en/segunda-familia-moedas.html

author: wraper
author_rank: Unknown
timestamp: April 26, 2021, 06:15:42 pm
content: Does not look anything like weight standard, not to say material is wrong. Weight standard must not oxidize.

author: vidarr
author_rank: Frequent Contributor
timestamp: April 26, 2021, 09:23:56 pm
content: I didn't even think of that. What a good idea. I have a few dollars worth of USA coins I can use.Thanks for the links too, I will use the USA coins, because Brazilian change is very low quality and......

author: vidarr
author_rank: Frequent Contributor
timestamp: April 26, 2021, 09:35:57 pm
content: ....Brazilian coins also oxidize. It is mostly made of iron. Thanks for the tip about that, makes total sense.I found that thing some random place in my in-laws tool-shop, not with anything that hints what it is for.My wife's dad passed away a few years ago, so it will remain a mystery I guess.Thanks guys!PS, I never weighed LSD before, but mushrooms and marijuana of course.Now, I have about 50 grams of saffron I bought in Turkey.Going to bag it in small bags to sell some, and a little for friends and family.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 26, 2021, 09:44:13 pm
content: I have the exact same scale. It is amazingly good - I use it to track the amount of ink used in inkjet print cartridges, so I know when to refill them... in the kitchen, it is great for weighing ingredients for making youghurt, sometimes less than 0.5g ...

author: vidarr
author_rank: Frequent Contributor
timestamp: April 26, 2021, 11:48:53 pm
content: Yes, I was really surprised how good it is. I bought it from Ali Express, China.Do you like the feel of it? I love the materials it is made out of.That rubber-like housing is so nice to touch. It is smooth, but has a really good grip and tactile feel.It won't slip from your fingers easily. And the leather sleeve it goes in feels like lambskin (it's not though).The price is even amazing.Highly recommend it to anyone looking for a digital scale.I sound like my family owns the scale company, LOL.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 12:24:58 am
content: Yeah, it exceeded expectations for me, too. Definitely second the recommendation!

author: Halcyon
author_rank: Unknown
timestamp: April 27, 2021, 08:49:52 am
content: That looks like a plunger or stopper of some kind, maybe from a tap or valve? I don't think the 3 means 3 grams.

author: Nusa
author_rank: Super Contributor
timestamp: April 27, 2021, 11:24:17 am
content: US Pennies are 2.5 grams for current issue, or 3.11 grams for those 1982 or older. A fair number of old pennies are still in circulation, if you look for them.US Nickels have been 5.0 grams since about 1965.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 12:23:19 pm
content: You can buy calibration weights cheap enough on eBay, Amazon, etc.This scale needs a weight accurate to 0.1g or better, ideally!

author: wraper
author_rank: Unknown
timestamp: April 27, 2021, 12:36:09 pm
content: Quote from: SilverSolder on April 27, 2021, 12:23:19 pmDepends on what weight. If it's several hundred grams, then OK. If it's 5 grams, then it's awful. Not to say you need something like a half of full scale to properly calibrate.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 01:07:40 pm
content: Actually I got that wrong, it needs to be 0.01g accurate.There doesn't seem to be a spec for the accuracy in the manual...For calibration, I have a 100g and a 10g weight, I calibrated with the 10g weight about two years ago - it has retained its calibration at 10.00g and still reads 10.00g on that weight after all this time!I just tried calibrating with the 100g weight for the first time, it now reads 100.00g (instead of 99.93g before calibration), and the 10g weight still reads 10.00gIt seems spookily accurate... seems you can trust it to at least 0.1%

author: DrG
author_rank: Super Contributor
timestamp: April 27, 2021, 02:33:42 pm
content: Quote from: Nusa on April 27, 2021, 11:24:17 am In 1982, both kinds of US Cents were made, copper (3.11) and copper plated zinc (2.5). That was the year I was referring to in post #2.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 03:12:13 pm
content: Weight of 5 random pennies, clean, shiny1. 2016 2.51g2. 2017 2.48g3. 2008 2.49g4. 2001 2.51g5. 2018 2.48gThis is repeatable to within 0.01g

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 03:21:03 pm
content: I never knew... super useful trick!US Coin WeightsQuarter: 0.2ozPenny: 2.5gNickel: 5.0gDime: 2.25g

author: wraper
author_rank: Unknown
timestamp: April 27, 2021, 05:24:26 pm
content: Quote from: SilverSolder on April 27, 2021, 03:12:13 pmThis is awful as far as calibration weights get, +/- 1% is junk. If you calibrate based on that, it could easily get you 10g off when measuring 1kg.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 11:06:14 pm
content: Quote from: wraper on April 27, 2021, 05:24:26 pmYes, you are far better off buying some "real" calibration weights, they are not that expensive.But, the weight of coins could be useful in some circumstances when 1% is "good enough for Australia".

author: wraper
author_rank: Unknown
timestamp: April 27, 2021, 11:11:44 pm
content: Quote from: SilverSolder on April 27, 2021, 11:06:14 pmBut scales most likely will be better than that even considering they were calibrated at place with different gravitational acceleration. So IMHO the most you can use them for is checking if scales are not displaying outright wrong numbers. Or making a rough calibration on scales which were calibrated a very long time ago and thus drifted a lot over time.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 27, 2021, 11:19:25 pm
content: Quote from: wraper on April 27, 2021, 11:11:44 pmI was thinking of rather extreme circumstance, e.g. you are camping, don't have a scale with you, and need to measure out an ounce of butter... and you do have five quarters!

author: Nusa
author_rank: Super Contributor
timestamp: April 28, 2021, 12:51:17 am
content: Quote from: SilverSolder on April 27, 2021, 11:19:25 pmOut of curiosity, how do you use the quarters if you don't have a scale with you?As far as butter goes, there's usually 4 sticks in a pound, so 4 oz per stick, so 1 oz would be 1/4th stick. And that information is generally marked on the stick wrapper as well. Alternately, you could just remember two tablespoons in an ounce. I'm aware that "ounce" is an ambiguous unit. For cooking purposes while camping, the weight and volume measures are close enough to the same thing in the case of butter. (Of course, real cooks are experienced enough to eyeball such things, even when the tools are available.)

author: Muttley Snickers
author_rank: Unknown
timestamp: April 28, 2021, 11:59:36 am
content: Down here many if not all Australia Post Offices have a decent digital weight scale on the front counter which one would assume is accurately calibrated on a regular basis. Sometimes when I go to pay a utility bill at the post office I quickly check the weight of my Asus Zenfone which is always 214 grams regardless of which post office I go to, my mobile phone has become a handy transfer standard.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 28, 2021, 02:42:13 pm
content: Quote from: Nusa on April 28, 2021, 12:51:17 amI can see, I should have put a smiley in there somewhere!OK so in the hypothetical situation where you need to weigh something to 1% and you don't have a scale, but you do have 6 quarters: you could make a makeshift balance out of random materials that you find, and balance it using three quarters on each side, before using the quarters for weighing the target material?

author: Kleinstein
author_rank: Super Contributor
timestamp: April 28, 2021, 03:24:00 pm
content: There are several ways to build a makeshift scale. For camping it could be as little as a plastic bag on a suitable branch and look for the same movement.For using the quarters as weight one may even get away with only 3 quarters if one has something else to get initial balance. The quarter acts double when moved from one side to the other.Gravity does not change that much, but for really high resolution scales it may matter. However than one may also care about humidity and temperature as it changes the air density and thus the buoyancy correnction.The scales at the post office may need to be quite good as they are used from something like a 10 g air mail letter to 30 kg parcel. For work I have a simialar one: 0.1 g resolution up to some 30 kg.The weight of a letters is a bit tricky however, it can change with humidity.

author: DrG
author_rank: Super Contributor
timestamp: April 28, 2021, 06:32:33 pm
content: In the spirit of this particular thread drift.....As already stated US cents in 1982 were either copper (3.11 gm) or copper plated zinc (2.5 gm). 1909-1981 are all 3.11gm and 1983-current are all 2.5 gm.To figure out which 1982 metal content you have, you can make a simple balance like the one shown herehttps://www.cointalk.com/threads/a-guide-to-1982-lincoln-cent-identification.55647/But, I can drift even further. Given 11 1982 cents (all 3.11 or 2.5) and one different weighted 1982 cent (either 3.11 or 2.5, depending on which you chose for the other 11). I bet you that using such a simple balance (in this case, we don't need the post 1982 cent at all, just a balance that can discriminate the two weights by up or down)only three times, I can determine, without fail, which cent is the odd weight and whether it is heavier or lighter than the other 11....and I never need to see the date at all.Not enough drift?How about lighting a red led using SilverSolder's 5 cents?https://www.exploratorium.edu/snacks/penny-battery(ok, and some salt solution, vinegar and cardboard).Anybody can drift the topic further ?Although one could make the case that the first example is definitely mathematical and programming and the second definitely electronics, so maybe they are side drifts to other topic areas.

author: Nusa
author_rank: Super Contributor
timestamp: April 28, 2021, 08:00:28 pm
content: Quote from: SilverSolder on April 28, 2021, 02:42:13 pmBut if you make a scale, then you DO have a scale with you! The extreme circumstance only applies if you DON'T have one.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: April 28, 2021, 08:25:54 pm
content: Calibrate it with a known volume of water. Got an old syringe or maybe a measuring cup from a cough medicine bottle? Good enough for cooking.See attached. Water filled to 25mL mark by eye and weighed on my analytical balance.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 28, 2021, 08:26:13 pm
content: It's easy enough to make a balance or a scale... much harder to calibrate it!

author: beanflying
author_rank: Super Contributor
timestamp: April 29, 2021, 07:48:59 am
content: Depends on the accuracy you need or if you are building something from scratch then having a set makes testing linearity really easy.I brought this set of calibration weights a year or so back for about $20. Interestingly they compare very well with the two 50g weights that came with my 100g cheap and cheerful scale I brought 7 or 8 years ago. No reason the cheap cal weights on evilbay won't be close and you can always cross check them against one known which I did initially with my set. I have used these smaller sets to check the larger digital scales I use for coffee roasting by filling small cups to a known 100g against them. Uncertaintybut a lot better than I need in particular when I cook