first impressions of the Lego smart brick, before I do any actual tearing down: wow, I forgot how good they are at working with plastic.
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@migratory fascinating!
@whitequark an anecdote from someone else here https://old.reddit.com/r/lego/comments/15wtg6n/melted_legos_what_happened_what_should_i_do/
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@whitequark do you have a hot wire?
@bob i don't have any nichrome at hand and i'm pretty sure i'd give myself burns if i tried
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if you've never heard of anybody opening welded plastic this way, i can now tell you why: because it's a bad idea. until you heat ABS to the point where it flows (which you don't want here, as it'll make later teardown even worse), it acts rubbery. imagine cutting hot rubber. doesn't work
@whitequark somewhere I got a little saw blade for my rotary cutter. It isn't a Dremel brand blade, and I've never seen it again, but it is perfect for stuff like this.
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first impressions of the Lego smart brick, before I do any actual tearing down: wow, I forgot how good they are at working with plastic. the injecton molding remains impeccable, at least for this specific piece (I know about their recent QC issues elsewhere)
it's hard for me to look at the positively microscopic (I am literally using a microscope to look at it) "Li-Ion" lettering and think of anything but "showing off!"
(treehouse doesn't let me attach the full size images, you can grab them here: front, side)
@whitequark Lego plastics are something else…
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@whitequark somewhere I got a little saw blade for my rotary cutter. It isn't a Dremel brand blade, and I've never seen it again, but it is perfect for stuff like this.
@danlyke yep. but I don't have any rotary cutter atm, had to get rid of 90% of my tools when moving to the UK
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if you've never heard of anybody opening welded plastic this way, i can now tell you why: because it's a bad idea. until you heat ABS to the point where it flows (which you don't want here, as it'll make later teardown even worse), it acts rubbery. imagine cutting hot rubber. doesn't work
@whitequark That certainly matches my experiences of working with ABS!
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if you've never heard of anybody opening welded plastic this way, i can now tell you why: because it's a bad idea. until you heat ABS to the point where it flows (which you don't want here, as it'll make later teardown even worse), it acts rubbery. imagine cutting hot rubber. doesn't work
it did however let me lop off the top of it easily
this is I think a 2.4G antenna?
next step is sanding
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it did however let me lop off the top of it easily
this is I think a 2.4G antenna?
next step is sanding
@whitequark thats supposed to be an antenna? I find fascinating how anyone engineered this into existence
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@whitequark thats supposed to be an antenna? I find fascinating how anyone engineered this into existence
@analog_feelings that is one of the more ordinary 2.4G antennas I've seen yeah
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@analog_feelings that is one of the more ordinary 2.4G antennas I've seen yeah
@analog_feelings but to answer your question, a combination of instinct, experience, and simulation. a lot of simulation. (and prototyping too)
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it did however let me lop off the top of it easily
this is I think a 2.4G antenna?
next step is sanding
yep that did the thing. probably should've started with sanding at the beginning.
it was somewhat more destructively than i wanted, but that's ok: i was trying to challenge my (incorrect) belief that sanding is always a tedious pan in the arse
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first impressions of the Lego smart brick, before I do any actual tearing down: wow, I forgot how good they are at working with plastic. the injecton molding remains impeccable, at least for this specific piece (I know about their recent QC issues elsewhere)
it's hard for me to look at the positively microscopic (I am literally using a microscope to look at it) "Li-Ion" lettering and think of anything but "showing off!"
(treehouse doesn't let me attach the full size images, you can grab them here: front, side)
@whitequark Copyright 2022 is also not what I would have expected.
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@whitequark thats supposed to be an antenna? I find fascinating how anyone engineered this into existence
@analog_feelings @whitequark yep - that's a MIFA - meandered inverted F antenna. The F just represents the shape the feed point and grounding pin make.
Really cool how they evolved to be like that:
dipole
monopole
whip (inductively loaded)
Inverted f (capacitively and inductively loaded)
MIFA
PIFA
and eventually chip antennas (also dialectrically loaded) -
@NULLderef it looks exactly like every smartphone driver ever
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@whitequark Copyright 2022 is also not what I would have expected.
@claudius the PCB has 2024 on it
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yep that did the thing. probably should've started with sanding at the beginning.
it was somewhat more destructively than i wanted, but that's ok: i was trying to challenge my (incorrect) belief that sanding is always a tedious pan in the arse
took it apart. there's a sort of a plastic "carrier" that gets manufacured first, then inserted into the final package that's welded shut
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took it apart. there's a sort of a plastic "carrier" that gets manufacured first, then inserted into the final package that's welded shut
@whitequark content of the data matrix code
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@Andres this is a tiny battery, i'd be fine
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@Andres this is a tiny battery, i'd be fine
@whitequark
I know, I'd made worst, but still
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took it apart. there's a sort of a plastic "carrier" that gets manufacured first, then inserted into the final package that's welded shut
okay, i've extracted the firmware-bearing parts. this is a tiny 45 mAh battery. (part of the lettering was torn off by the glue it was attached with)
