Aldi digital scale

[Poignard]

https://www.aldi.co.uk/crofton-digital-scales/p/086864253274300

I bought one of these for weighing small quantities of epoxy resin and hardener.

Good value at £6.99, including battery

 

[LittleSister]

I would be surprised if something that can weigh up to 5kg will accurately weigh a few grams.

The digital readout may well be giving a spurious impression of precision.

 

[Poignard]

I would be surprised if something that can weigh up to 5kg will accurately weigh a few grams.

The digital readout may well be giving a spurious impression of precision.

You may be right. I will test it and report back.

Although I am less concerned with knowing the weight accurately in grams than that the ratio of hardener to resin is accurately 1:5.

 

[peteK]

I bought one of these Aldi scales a few years ago and it is surprisingly accurate,it does stop working when it gets damp during winter but ok once dried out.

 

[Poignard]

Indicated weight of 1 penny piece = 3 grammes
Indicated weight of 5 penny pieces = 17 grammes

Indicated weight of 1 twopenny piece = 7 grammes
Indicated weight of 5 twopenny pieces = 35 grammes

That's accurate enough for me.

 

[GHA]

I would be surprised if something that can weigh up to 5kg will accurately weigh a few grams.

The digital readout may well be giving a spurious impression of precision.

Be surprised The cheap 5Kg scales I use for epoxy accurately weigh euro coins down to 1g.

 

[Spirit (of Glenans)]

To check the accuracy of a scale under small quantities, put an empty cup on it, set it to zero, then add water, from a medicine dosing cup, for instance. Water weighs 1 gram per cc.

 

[Motor_Sailor]

To check the accuracy of a scale under small quantities . . .

Absolute accuracy is unimportant. The units can be anything. The amount of epoxy you need for a little job is normally gauged by eye.

The critical function of the scales is to make sure that only 1/5th (or other ratio) of the weight of the resin is added as hardener.
So the test using one and five coins as above is perfect.

 

[GHA]

Absolute accuracy is unimportant. The units can be anything. The amount of epoxy you need for a little job is normally gauged by eye.

The critical function of the scales is to make sure that only 1/5th (or other ratio) of the weight of the resin is added as hardener.
So the test using one and five coins as above is perfect.

Also wise to check the weight against volume of each component to check the ratio by weight. ISTR someone on here was given the wrong figures from a supplier and had to strip and repaint some epoxy.

 

[JumbleDuck]

I would be surprised if something that can weigh up to 5kg will accurately weigh a few grams.

13 bits will resolve 5kg maximum down to about 0.5g. Would anyone digitise the output of a load cell at under 15 bits, leaving one for sign?

I bought a similar set of scales for my kitchen at Lidl last week. They seem to work fine.

 

[[70521]]

13 bits will resolve 5kg maximum down to about 0.5g. Would anyone digitise the output of a load cell at under 15 bits, leaving one for sign?

Can we start discussing negative binary as well? Reminds me of my undergraduate days.

 

[AntarcticPilot]

13 bits will resolve 5kg maximum down to about 0.5g. Would anyone digitise the output of a load cell at under 15 bits, leaving one for sign?

I bought a similar set of scales for my kitchen at Lidl last week. They seem to work fine.

A sign bit is only needed if it has the facility to subtract the weight of a container, which I guess most do - my Salter kitchen scale does, and it is very useful! Zeroing the scale with a weight on it and then removing the weight gives interesting displays.

 

[Poignard]

..d had to strip and repaint some epoxy.

I don't envy him that job!

 

[JumbleDuck]

13 bits will resolve 5kg maximum down to about 0.5g. Would anyone digitise the output of a load cell at under 15 bits, leaving one for sign?

By happy coincidence I had lunch today with a friend who recently spent some time designing a digital scale system - in his case to allow couriers to check loading in vans.

He tells me that for his system they used 12-bit accuracy on cheap components with no problems at all. He thinks that 13-bit accuracy would be fine, but that after that noise would be a serious problem and the component cost would have to go up. He doesn't think that there would be any problem in designing a scale which would go up to 5kg and resolve to 1g at the Aldi/Lidl price point.

By another curious coincidence, I also know the man who designed the scales used on Tesco automatic checkouts. That's one hell of a debt to be repaid to society. Unexpected item in bagging area.

 

[JumbleDuck]

Can we start discussing negative binary as well? Reminds me of my undergraduate days.

<Shudder> Two's complement!

 

[neil_s]

I use mine to check-weigh the Life Jacket gas bottles.

 

[Poignard]

From now on its two penn'orth of 205 and ten penn'orth of 105.

 

[elton]

They're very popular amongst drug dealers, apparently.

 

[peteK]

Since I bought mine I have been checking the weight of everything its surprising how many groceries are underweight,
prepacked cheese in particular.

 

[Lon nan Gruagach]

Also wise to check the weight against volume of each component to check the ratio by weight. ISTR someone on here was given the wrong figures from a supplier and had to strip and repaint some epoxy.

Right on:
SP Gurit 106 is 5:1 by volume and 50:9 by weight. Cheapo digital (drug dealer) scales from eBay worked a treat. You quickly learn how much to mix for the immediate task, units are irrelevant.