So, I’ve had this in my box of bits from
AliExpress for quite some time, and I
just saw Big Clive do a tear down on one
of them. So, I thought, let’s have a
look and see what’s inside.
So, this is a bstable coliseric display.
So what we can do is we can write on it
and then you just hit this button and it
clears. So you should like um subscribe
like the video, subscribe to the
channel. But let’s uh let’s pop this
open and see if we can uh work out how
it works. But before we do that, a quick
shout out to PCB Way. I’m testing out
some recent boards for them. They came
out really nicely. Check out the link in
the description.
Okay. So, it’s uh it’s pretty simple. Um
does actually still work. So, that’s
good. And we can see we have uh two
layers. Now, obviously, Big Clive took
it apart and messed around with the
liquid. I think he may have even tasted
it. I’m not quite so brave, but there
are two layers. So in between these two
layers is some uh some crystals which
are these bstable coleric crystals. So
in one state they’re transparent and
then you apply a quite high voltage and
they all line up. So let’s let’s see if
we can um measure the actual voltage
that’s being zapped onto the board.
Put it on voltage DC.
Interesting.
So, it seems like it jumps up to around
30 volts and then drops down again. What
I might do is try this on the
oscilloscope. See if we can get a a nice
trace of it.
[Applause]
Okay, there we go. Got a nice capture of
it. 26.8
as the peak voltage. So that’s pretty
good. So wonder if we can try um zapping
this just with a power supply to see if
it works. I wonder if the actual signal
shape even matters. So still working. Uh
let’s just check the polarity. So I
think that was the plus. That was the
minus. And my little power supply here.
So let’s plug this in.
Okay, so I’ve got my output set to 30
volts.
Let’s uh let’s draw some stuff. Let’s
clear these cables out the way. Draw a
bunch of random squiggles. Now, in
theory, if we just touch
these two here, it should clear.
It works.
So, that was the So, plus is this one.
negative is this one.
30 volts gone. Amazing. Well, that’s
that’s pretty cool. I mean, these are
very simple, but um but if What happens
if we do it the other way around? Or do
we actually break it? So, let’s do let’s
do plus here and minus here and see what
happens.
We got a spark, but it still cleared it.
Maybe I shouldn’t do that. Not a good
idea, Chris. Not a good idea.
So, uh, yeah, that way around works
nicely. Probably should have
disconnected the battery before messing
around like this, but uh, nothing’s
blown up. So, that’s completely fine,
isn’t it? Oh, fun bit of kit. Wonder if
I can, um, can I repair this? So, pretty
simple construction, but uh, interesting
nonetheless. So, if you want to see the
um, reverse engineing of this, just hop
over to Big Clive’s channel. He’s uh, he
is the reverse engineering king. and
he’s done quite a good job with that.
So, I won’t I won’t duplicate his
efforts.
Let’s stick this back on. And there we
go. It’s as if we were never here. Um,
the perfect crime. So, yeah, that works
really well. So, like and
subscribe.
Have I broken it? Oh no. How have I
managed to break it?
Well, it was very cheap, so doesn’t
really matter.
Well, it is broken, but I have my manual
solution. I can just do it manually. I
might try and have a look at this PCB.
See if I’ve uh see if I can fix it, but
I probably blew it up when I um put the
reverse voltage on. So, bit silly on my
side. Never mind.
So, we can clear our screen. There we
go. Perfect.