flexible led filaments i thought i'd get
some and strip one of them apart and
take a look it turns out they're quite
hard to strip apart i was hoping i was
going to be able to peel some of the
silicon off to reveal the circuit board
but as it happens uh
any attempt to actually scrape it very
gently the knife ended up just cutting
the circuit board and then when i cut
bits and uh off i put them in various
solvents to hoping that i could dissolve
the silicone and reveal the circuit
board no luck but that's okay because
what i actually did in the end was i
illuminated a controlled intensity and i
stuck a magnifying glass glass over it
and duded it down and then created a
graphical representation which i will
come to in a moment it's a very
interesting construction
so the reason i got these is because
another youtuber who makes models
had made a model of a neon sign and
they'd use this so it's a scale model
but it had this very sharp outline of
this stuff and the stuff operates at
three volts per section so basic at four
sections here and at the moment it's at
12 volts and it's passing 200 milliamps
the 200 milliamps equates to just one
milliamp per led in here because there
are 200 leds in each section of this
i worked out that in the 285 millimeters
that is lit up that's about 11 inch
there are 200 leds so roughly 7 per 10
millimeter
the circuit board inside appears to be
1.5 millimeter wide and then it's coated
in the phosphor now it's worth
mentioning the seller i got these from
on aliexpress is selling what appear to
be slight rejects and it's not an issue
for people like us that are just
experimenting with them
but if you look along it and you're not
really going to see it because uh you
certainly wouldn't see in the distance
but
i can see right now there are
occasionally dark bits along it and it's
not because the leds are out it looks as
though the leds have flipped up sideways
and are actually projecting light out
the side instead and that's viable for
the way they're soldered on
so let me
bring in a doodle and show you the
construction of this
i shall also zoom down slightly
zooming down
so the circuit board is a very thin
flexible circuit board very delicate
and it has a pad on each end
and then
a series of uh pairs of pads with what
appear to be flip chips flip chips are
leds that basically have little solder
pads on them the bare chip itself so
it's almost like a surface mount led but
there is no package it is just the bare
led it's the way a lot of stuff has gone
and what it means is that they can apply
probably a continuous process they can
apply a solder paste onto these little
pads they can use a machine that and
goodness knows how it does it because
they're tiny
that picks and places the leds on and
then it will take them into a reflow
oven it will heat the soil drop and it
will flow on and soda them
that's where i think some of these
little leds
are sitting across like that to think as
the sodas they're flipping up in their
end like that
because the light distinctly shines out
the side for some of them and the
arrangement they've got you've got the
positive end and the negative end
they
have the large pad
thermal isolation going over to the
first led and then
they've got a bus going up one side that
connects to the positive all the leds
and then the other side is a bus that
goes down all the negatives and that
means that theoretically
this led here
has the same sort of circuit resistance
as the led in the middle because the
tracks the same length but in reality
and i'm not sure why this is the green
is visibly brighter at one end uh at
both ends actually but duller in the
middle as is the blue i'm not sure why
the current isn't shearing equally i
wonder if that's part of the degradation
the middle with the flowing process i'm
not really sure
but uh
this arrangement means that these leds
are these whole filaments just operate
at three volts
because all the leds are effectively in
parallel let me bring in a notepad
and doodle oh there's another pen i
should use that one
so the construction is this
they have the circuit board
with the little tiny chips mounted on it
and then they coat it with a phosphor
loaded gel and the other side is coated
with slightly less phosphor coated gel
it's more translucent the other side
and any light that gets bounced off the
top also goes through the circuit board
and comes through the bottom
to terminate onto
the strip at the end
has
a
crimp put on it a little crimp that just
basically goes under it like this and
folds around and bites into that copper
pad at the end
and that's the connection then they seem
to secure and place the little blob of
silicone and then put that sort of the
phospholoaded silicone on it it's very
neat
the crimp itself when it comes off the
end
has a
little tag that comes off like that
the positive one has a hole through it
just in case you get some of these
there's a one of the tags is no hole
it's a negative one of the tags as a
whole it's positive just for reference
that's how to identify them
the colors
uh you've got the sort of warm white
it's goldeny white you've got the green
the blue and the pink this is red but
red doesn't work that well it's nowhere
near as bright as the other colors
but that's because the
red
doesn't really want too much blue
and blue is the main stimulating
led that stimulates the phosphorus so
they have to use quite a thick layer of
phosphor to get the red but actually
hide the blue from say otherwise you'd
end up with a pinky color so this one is
a fairly dark red
i should show you it shouldn't i i
should one moment please
and back again uh here is the red and
again it's got a real hot spot at the
end but dim in the middle i'm not sure
why that is but you can also see
the irregularity of the leds in this
stuff it's really pretty visible i shall
zoom down a bit so you can
marvel at the irregularity hi it was
cheap i knew what i was getting
i'm just glad that all the leds are lit
but it's notable that the ones uh that
where there's a gap it's you twist it
slightly and uh it seems like they're
just pointing light out the side very
strange i'm not sure why that is
if they've just flipped up or it's
something else
and the red though not as bright as
others it's worth mentioning that uh you
run these at three volts and uh
i would say one milliamp per led is
ample i'm not sure what they're rated
but certainly
that would equate to three volts 300
milliamp 200 milliamp that would be 0.6
watts i suppose you could run them
higher they're not really going to be
too pushed i'm not sure they're rated
but i think they're more designed as a
visual effect you'll often find these in
the lights spiraled round with big long
gangly filaments and little supports
and quite nice that they're low voltage
though it opens up possibilities of
using them in sort of like costume
effects
and they're very resilient i did manage
to damage one though i put in a
connector and then i really absolutely
flailed it off the table to see if i
could break it and what i did manage to
do is break one of the solar connections
and also fracture the circuit board with
the flexing where it went onto one of
the connectors so if you reckon there's
going to be a lot of movement put a bit
of heat shrink sleeving over the end
just to actually reinforce it i've
actually put heat shrink sleeving where
i've soldered these end to end and
because i've got four of them
the four times three it runs at 12 volts
but uh i would go by
limiting the current i'd adjust it to
whatever
it limits the current to a safe level
for these
so i shall provide a link to where i got
these but be aware that they are kind of
reject factory rejects they're just for
playing with and also be aware that
sometimes when i provide links to
aliexpress sellers the price goes
through the roof it sometimes happens it
happened with this i made a video about
this little uh
portable soldier yarn
one two three four five right that's it
and the seller just hiked the price up
uh more than double so i removed the
link and i told them why i'd removed the
link
um they just sent a wee question mark
back to me no i don't know if they
understood what i was saying i was
saying stop being dicks
however it's also worth mentioning that
there are other tempting things
available from this seller like colorful
solid led filaments these are the higher
voltage ones
but
these ones arrived intact and these ones
all arrive broken and they're they were
shipped in ten little bags just in
amongst other stuff and you're thinking
oh maybe they've broken the shipping
but i've had experience with buying the
filaments from china i get the feeling
that they quite often just throw the
broken ones into the packaging as well
so i'm not sure if they were broken in
shipping or if they were broken
before shipping however they weren't
packaged correctly just be aware of that
if you consider buying the the solid
filaments
but that is it so what you see is kind
of think of for this well it's just a
visually nice thing you could make
yourself a necklace out of it i suppose
with a little uh battery pack because it
doesn't
take much current even at just 10
milliamps it glows quite brightly
it's pretty good
um
but really it's just
whatever you want to do that
fundamentally it produces a nice sharp
line of light but that is it that's how
they make it uh the construction inside
i'll check back later and see if the
stuff that i put in the solvent has
dissolved in any way sometimes the
silicons kind of puff up when you put
them in acetone and things like that but
so far no luck but if that i do have
luck i'll maybe make a note down below
in the description or
whatever
but anyway that's it the
gangly very flexible led filaments