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Using Euro coins as weights (2004)

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180 points Tomte | 7 comments | 20 Oct 24 10:18 UTC | HN request time: 0s | source | bottom
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rchowe ◴[20 Oct 24 12:11 UTC] No.41894824[source]▶
I built a computer vision device that used the top-down area of a penny as a calibration standard. Coins are useful, easy-to-get items that have relatively tight manufacturing tolerances.
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cassepipe ◴[20 Oct 24 12:35 UTC] No.41894944[source]▶
What about wear ? Were they only new coins ?
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1. Retric ◴[20 Oct 24 12:37 UTC] No.41894957[source]▶
I’ve never seen significant ware on a coin in circulation.

Have you?

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2. seqizz ◴[20 Oct 24 12:49 UTC] No.41895028[source]▶
I've seen enough wear to prevent them to be calibration material at least.
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3. ◴[20 Oct 24 13:13 UTC] No.41895157[source]▶
4. MadnessASAP ◴[20 Oct 24 13:33 UTC] No.41895266[source]▶
Depends on what your tolerances are. If you only need to be within a mm a coin is going to beat that by an order of magnitude.

We use a pack of cigarettes as a gauge for one of the jobs we do. Quick, (not so) cheap, and readily available. May have to standardize on a vape though in the near future.

5. swores ◴[20 Oct 24 14:02 UTC] No.41895428[source]▶
I have often, though I suspect not enough to make a significant difference to someone who is already OK with the slight variance between un-worn coins.
6. xboxnolifes ◴[20 Oct 24 18:24 UTC] No.41897412[source]▶
I have coins that originally had milled edges that are now completely smooth.
7. fanf2 ◴[20 Oct 24 20:13 UTC] No.41898161[source]▶
Only on counterfeit £1 coins, before the coins were redesigned to make them harder to fake