Cheers,
I should have just done that.
I was waiting for a reply so I could have sent any requested file Hamspiced asked for to make it easy, rather than ALL of them ( There are a lot )
Saw y’all talking and couldn’t help but take a whack at it for practice.
My rough attempt based on @Pilgrimsmaster’s measurements:
Couldn’t really think of how to make the bands on the bottom curve like the real thing, but I think the rest turned out pretty well.
.step file since someone asked for it.
.3mf file in case anyone wants to print it.
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I think you did really well. 
2 things,
real thing is rubber, so flexy and curve naturally anyway
how to curve will depend on how you drew it.
Can you show your pre rendered sketch?
For printed design, for strength, you would want to soften some of the sharp edges, by putting some fillets in around the stress points, (around the strap areas.
Sounds critical 
but again, nice work
Damn, you beat me to it, i was just finshing typing up a reader project and i was gonna draft this quickly tonight but you did a great job. Excellent work.
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I know very little about 3D files, but would it be possible for you to expand the whole thing so that the area the watch band passes through has a length of 26mm while leaving the space inside for the chip the same size? I would like to get this printed to fit on my Apple Watch Ultra sport loop band.
I’m also wondering if a person can simply upload this file to a 3D printing service directly or if it needs more configuration to tell the printer how exactly to make the print.
TIA for any advice.
I can, but if it’s going to be printed in flexible material like TPU, wouldn’t you want it to be slightly undersized so that it will stech and fit around the band snuggly without sliding?
I’ll be honest, I’ve never worked with TPU or designed something to stretch like this so I don’t know the appropriate amount of undersizing to do, but I will go and make a 26mm version for you when I get the chance.
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My 2 cents,
You may want to look into either printing it out of something rigid, and using it as a positive to make a negative mold
Or you could try to print a negative mold,
You would have a much stronger part with no layer adhesion to worry about, and may be easier to print
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The watch band I’m using on the Ultra is cloth, so it would likely just deform the watch band instead I think.
Can I read default chip with this module ?
Yes, it should be compatible. Be warned, this technology might get under your skin…
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I wish I had seen this post a few weeks ago. I literally went though the same experimentation process.
- This watch band gets recommended to me by Amazon
- I buy it thinking it might be a T5577 in disguise
- I find out it is not a T5577
- I install my own T5577 chip in the rubber housing
- I think “Hey I could 3D print this out of TPU”
Great minds think alike I guess 
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After about 4.5 months
I’m going to eat crow about that.
About a week ago I found the chip on the lounge room floor.
So it appears it is a genuine issue.
I still haven’t replaced it with a T5577, but I will start looking again for one that will fit and share here when I do.
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I actually swapped mine for a T5577 that I got on AliExpress:
$7.18 | ID 125KHz Micro size 10MM wriatable COB coil tag T5577 chip antenna RFID passive cards tags with EM4100 EM4305
https://a.aliexpress.com/_mrWiCaa
I determined that some googly eyes I had laying around have a very similar casing to the original chip. So I cut open a googly eye, removed the pupil, put in the chip and filled The cavity with super glue.
It was a slightly looser fit than the original and The backing was white instead of black.
So to solve that I wrapped it in electrical tape to prevent it from wiggling out and so it would match nicer
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Haha, I love it.
Thats a great mod
And I just happen to have some googly eyes (What self respecting man doesn’t???)
Thanks for providing links too.
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No problem! I made that one for a friend of mine so he can get into his apartment building with his Apple Watch. But I had a bunch of extra T5577 tags so I also made a couple more googly eye tags to test the 3D printed version that @StarGazer1258 made.
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Have you actually printed one? Did it work well? Would love to see it of if you make one. I never actually got to test the model, as I don’t have any TPU filament, nor a direct drive printer.
I haven’t printed it yet, but I think I am going to try to modify it to be able to accommodate this dual frequency coil combo:
https://www.aliexpress.us/item/3256804252007898.html
I’ll let you know when the chips I ordered get here 
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Nice. Have you thought about using liquid electrical tape to hild the coil in place? Also works great for water protection. Can be easily peeled out as well.
The gen2 tags i use are gen2 mifare magic
https://a.aliexpress.com/_EzGW7Ub
Although i rudimentary coat them in liquid tape and then hold them on the strap with hockey tape.
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I used PlastiDip for mine
Pretty much the same thing
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