> What about the blue/purple ones? You know, like they had on ancient
> laptop screens?

Passive matrix too. The key difference is there is no electronics 
per-pixel to hold the voltage over the length of the frame, so the LC 
response time must be very slow (much longer than 1 frame) to keep any 
decent contrast. On an active matrix display the pixel electronics 
(transistor + capacitor) can keep the voltage at whatever you last set 
it to for the duration of a frame, so an LC material with very fast 
response can be used (eg 1 or 2 ms is common now in monitors).

> Wow. I didn't expect it to be quite *that* cheap. Even a simple resistor
> costs more than that! (Or maybe it doesn't if you buy a thousand of
> them, IDK.)

If you want 1000 or more you don't buy them from maplin, RS or Farnell. 
Try this:

http://www.aliexpress.com/item/High-quality-character-LCD-7-segment-LCD-module-3-3V-TN-positive-reflective/32293200442.html


cost must be significantly cheaper:

http://www.amazon.co.uk/Sharp-EL-240SAB-Calculator/dp/B0002I8VLU

>> Price is roughly proportional to screen area (the factory doesn't care
>> much how many screens it gets out of each "mother sheet").
>
> Linearly proportional? Or is it "more expensive" to buy really big screens?

Roughly linear - the factory costs to run are mostly independent of how 
small they chop up the glass at the end.

The only complicating factor is yield. If you get a dead pixel within a 
display then you can't sell it at the "dead pixel free" price. Obviously 
if you are making two huge TVs from each sheet of glass it is much more 
likely you have to scrap (or sell at a discount) 50% of the glass area, 
but if you're making 200 mobile phone screens you might only have to 
scrap 2 or 3 of them.

> OK. Again, that's not nearly as much as I thought. Makes me wonder why

> makes it a high-colour touch-screen device...




http://www.gearbest.com/lcd-led-display-module/pp_231779.html

> I imagine touch would be really expensive - but IDK...

The expensive bit in capacitive touch is the controller IC that does all 
the processing. There is also a premium on this because of the IP that 
has gone into the algorithms etc. The physical bit is very cheap, it's 
just another sheet of glass with some quite chunky conductive layers.

> I don't know, but I'm guessing it must be reasonably expensive to

> something?)

A good rule of thumb for medium-volume consumer goods like that is that 
the cost to manufacture is roughly 25%-33% of what you pay. The rest is 
VAT, shipping/logistics, paying for everyone who works in all the 
companies involved, and maybe a little bit of profit for each company 
along the way.

> Sure, but you don't *make* the switch yourself, surely? You buy an
> off-the-shelf microswitch,

Someone else needs to make it though, my point was for their size/weight 
switches are much more expensive than a sheet of bent metal because the 
assembly costs are higher (whoever does it).


> machine is one of those rare objects that contains *metal*. Obviously

> it. IDK, but I doubt it. The machine is also probably quite awkward to
> physically assemble. And they're large and heavy, so storing and
> shipping probably isn't cheap.

You might be interested in something like this, it gives a detailed 
breakdown of the costs of the parts in the latest iPhone (if you didn't 
know this is a very high-end phone that is expected to sell in high 
volumes):

http://www.techinsights.com/teardown.com/apple-iphone-6/

Post a reply to this message

On 13/10/2015 08:27 AM, scott wrote:
>> What about the blue/purple ones? You know, like they had on ancient
>> laptop screens?
>
> Passive matrix too. The key difference is there is no electronics
> per-pixel to hold the voltage over the length of the frame, so the LC
> response time must be very slow (much longer than 1 frame) to keep any
> decent contrast. On an active matrix display the pixel electronics
> (transistor + capacitor) can keep the voltage at whatever you last set
> it to for the duration of a frame, so an LC material with very fast
> response can be used (eg 1 or 2 ms is common now in monitors).

OK. So what's the difference between the silver ones and the purple ones?

>> Wow. I didn't expect it to be quite *that* cheap. Even a simple resistor
>> costs more than that! (Or maybe it doesn't if you buy a thousand of
>> them, IDK.)
>
> If you want 1000 or more you don't buy them from maplin, RS or Farnell.

[Rant] I remember when Maplin used to sell electronics. Now they're just 
a white-box shifting company. You used to be able to go in and just 
*buy* a string of 30 resistors or something. Now they're all like "oh, 
you want 10? Ooo, we'll have to order those in specially. We only have 4 
in stock." WTF?

> Try this:
>
>
http://www.aliexpress.com/item/High-quality-character-LCD-7-segment-LCD-module-3-3V-TN-positive-reflective/32293200442.html

That's... a dollar per display? Damn, you can't get too much cheaper 
than that. I wonder what a Z80 costs these days...


> cost must be significantly cheaper:

Well, I guess that's true enough!

>>> Price is roughly proportional to screen area (the factory doesn't care
>>> much how many screens it gets out of each "mother sheet").
>>
>> Linearly proportional? Or is it "more expensive" to buy really big
>> screens?
>
> Roughly linear - the factory costs to run are mostly independent of how
> small they chop up the glass at the end.
>
> The only complicating factor is yield.

Yeah, I thought that might be the case.

>> OK. Again, that's not nearly as much as I thought. Makes me wonder why

>> makes it a high-colour touch-screen device...
>


>
> http://www.gearbest.com/lcd-led-display-module/pp_231779.html

Damn, that's not bad at all! I'm surprised nobody seems to be using these...

>> I imagine touch would be really expensive - but IDK...
>
> The expensive bit in capacitive touch is the controller IC that does all
> the processing. There is also a premium on this because of the IP that
> has gone into the algorithms etc. The physical bit is very cheap, it's
> just another sheet of glass with some quite chunky conductive layers.

Interesting. I thought all the extra faff of assembling it was the 
expensive part.

>> I don't know, but I'm guessing it must be reasonably expensive to

>> something?)
>
> A good rule of thumb for medium-volume consumer goods like that is that
> the cost to manufacture is roughly 25%-33% of what you pay. The rest is
> VAT, shipping/logistics, paying for everyone who works in all the
> companies involved, and maybe a little bit of profit for each company
> along the way.

Interesting. And here I was thinking the metal is expensive. ;-)

>> Sure, but you don't *make* the switch yourself, surely? You buy an
>> off-the-shelf microswitch,
>
> Someone else needs to make it though, my point was for their size/weight
> switches are much more expensive than a sheet of bent metal because the
> assembly costs are higher (whoever does it).

Well, I guess.

Now you're typical calculator has one of those rubber keypads. I have 
personally assembled those; it's a sheet of rubber, and there's some 
wiggly traces under it. Presumably that's cheaper than a microswitch? 
(Especially given a calculator has, like, *a dozen* buttons...)

> You might be interested in something like this, it gives a detailed
> breakdown of the costs of the parts in the latest iPhone (if you didn't
> know this is a very high-end phone that is expected to sell in high
> volumes):
>
> http://www.techinsights.com/teardown.com/apple-iphone-6/
>


This is interesting on several levels.



2. I didn't know this kind of disassembly was legal. I thought Apple 
would try to sue you for distributing trade-secret information.

3. As expected, the display is the most expensive bit. (Then again, 
isn't the iPhone kind of renound for having a particularly high-quality 
screen?)

4. The next most expensive bit is the CPU, like you'd expect. The RAM 
looks surprisingly cheap tho. (No idea how big it is, mind you!) I 
wonder what kind of CPU... it... er... oh right, it's a custom ARM SoC.

5. I expected the battery to be way, way more expensive than that. 
(Considering that battery life is extremely critical to product success, 
you'd expect the best performance part that can possible fit in the space.)

6. I have no idea WTF "BB+XCR" is.

7. I enjoy that "Other" is nearly as expensive as the CPU.

8. Qualcomm manufactured my lawn mower. They make silicon too? WTF?

Post a reply to this message

>> OK. Again, that's not nearly as much as I thought. Makes me wonder why

>> makes it a high-colour touch-screen device...
>


Actually, the Raspberry Pi is kind of interesting...



When I first heard about it, it was billed as the BBC Micro for the 21st 
century. It's supposed to be a disposable-priced computer that will get 
kids interested in computer programming.

...expect that you can realistically write bare-metal code for an 8-bit 
PC with nothing more than a list of I/O register memory addresses and a 
weak knowledge of binary. I actually did this as a 10 year old child on 
my dad's Commodore 64. I wrote a tiny machine code program with pencil 
and paper. (We couldn't afford an assembler program, but I had an opcode 
table, and no friends or social life.)

By stark contrast, you can't do that on a Raspberry Pi. I mean, you 
*literally* can't do that; the hardware specs for the GPU are propriety. 
You can only look at them if you sign an NDA. Even Raspbian has to use a 
closed-source binary blob to drive the video hardware. If the Linux 
gurus of the Internet can't do this stuff, a kid has *no* chance! :-P

Yeah, it's kinda cool that you have this little circuit board that's 
super-easy to hook up to your computer, and to control other stuff with. 
But are kids really going to be that interested? Probably not.



Having looked around, it appears that the Raspberry Pi has actually 
spawned an entire new market sector of imitators. There is now the 
Orange Pi and the Banana Pi. (No, I'm not making this up!) Both made by 
companies completely unrelated to the Raspberry Pi Foundation. There's 
the utterly unpronounceable Arduino. There's the BeagleBoard and 
BeagleBone. Indeed, it seems that single-board computers are a "thing" 
now. Everybody wants a piece of the pie!

The specifications of some of these devices look amazing! For example, 
while the most powerful Raspberry Pi system has a single-core 700MHz CPU 
and 0.5GB of RAM, the Banana Pi has a dual-core 1GHz CPU and 1GB of RAM. 
And the Orange Pi has a quad-core 1.6GHz CPU!

...and then you look at the price tag. And you realise why. The original 
Raspberry Pi might have been designed to be a low-cost, disposable 
component, but some of the more powerful boards are priced at *hundreds* 
of dollars. You could buy an *actual* computer for that! (Although it 
would be way bigger, obviously.) Just because it's a naked circuit board 
with no case, doesn't automatically mean it's cheap. ;-)



Due to my boss existing, I've started reading Hackaday. I was amused the 
other day to see that somebody is trying to build an open-source mobile 
phone out of a Raspberry Pi. So... you're taking a SoC originally 
designed for the mobile phone industry, and trying to make a mobile 
phone out of it? What a rebel. LOL!

Still, the other day I found myself vaguely toying with the idea of 
getting a small tablet, just so I can sit in the corner coding when 
we're in a deserted forest or something. But why bother paying several 
hundred pounds for a tablet if you can actually buy a Raspberry Pi and a 
touchscreen for less than the cost of a pub meal?

Mind you... I've yet to actually *see* a Raspberry Pi on sale anywhere 
for the reputed price of $15. :-P For example, Maplin want to charge you 


(Oh, I'm sure the packet contains way more than just the circuit board. 
But that's the only bit I actually *want*...)

Post a reply to this message

On 10/13/2015 8:17 PM, Orchid Win7 v1 wrote:
> [Rant] I remember when Maplin used to sell electronics. Now they're just
> a white-box shifting company. You used to be able to go in and just
> *buy* a string of 30 resistors or something. Now they're all like "oh,
> you want 10? Ooo, we'll have to order those in specially. We only have 4
> in stock." WTF?

Funnily enough, I went into Maplins yesterday and bought 10 of 20 mm 
6.3ma slow blow fuses, off the shelf. (As an after thought)

-- 

Regards
     Stephen

Post a reply to this message

Orchid Win7 v1 <voi### [at] devnull> wrote:
> On 11/10/2015 08:43 PM, nemesis wrote:
> > orchid, do you ever submit your lengthy rants to
> >
> > http://thedailywtf.com
> >
> > ? :)
>
> Why? Do you think I should? :-P

sure, why limit your reading audience to the tiny povray newsgroups?

your rants are often amusing...

Post a reply to this message

Am 13.10.2015 um 21:17 schrieb Orchid Win7 v1:

> OK. So what's the difference between the silver ones and the purple ones?

The colour ;)

No, seriously - the silver ones are the "reflective" type, designed to
use ambient light for illumination (sometimes exclusively, sometimes
with an optional "backlight" for situations where ambient light is too
low), while the purple ones are of the "transmissive" type, designed to
be always used with a backlight (usually dot matrix with active-white
pixels).

> 2. I didn't know this kind of disassembly was legal. I thought Apple
> would try to sue you for distributing trade-secret information.

The whole idea of trade secrets is that you keep them secret /because/
you can't sue anyone if the information gets out into the wild.

Also, there is no way you can prohibit anyone from reverse-engineering
your inventions unless you make them sign a non-disclosure agreement.
For instance, once you have legally obtained a copy of a piece of
software, you can freely reverse-engineer it as long as you don't accept
the EULA (which in most cases means you can't install it, so you'll need
to reverse-engineer the installer as well).

What you often /can/ prohibit is the /use/ of the intellectual property
someone has reverse-engineered from your product.


> 8. Qualcomm manufactured my lawn mower. They make silicon too? WTF?

I didn't know they made lawn mowers.

Post a reply to this message

Am 13.10.2015 um 21:44 schrieb Orchid Win7 v1:

> Mind you... I've yet to actually *see* a Raspberry Pi on sale anywhere
> for the reputed price of $15. :-P For example, Maplin want to charge you


Might be a different model. AFAIK there are four models by now: The
original A and B models, and the 2nd generation A and B.

Post a reply to this message

> OK. So what's the difference between the silver ones and the purple ones?

No idea (we only made colour active matrix LCDs) - although I guess it 
might have something to do with the silver ones being reflective and the 
purple ones being transmissive (having a backlight)?

> [Rant] I remember when Maplin used to sell electronics. Now they're just
> a white-box shifting company. You used to be able to go in and just
> *buy* a string of 30 resistors or something. Now they're all like "oh,
> you want 10? Ooo, we'll have to order those in specially. We only have 4
> in stock." WTF?

- Plan in advance and buy from ebay
- Buy one of those 1000 piece packs of resistors of various values for a 
few pounds
- Get a job somewhere that has a ready supply of electronic components :-)

> Yeah, I thought that might be the case.

Interestingly even if a person goes through all the strictest clean room 
processes and clothing requirements the yield still drops noticeably 
when they go into the production area (and for some time after they have 
left). For this reason usually nobody is allowed in there unless for a 
very good reason.

> Interesting. I thought all the extra faff of assembling it was the
> expensive part.

Even a whole minute of additional manual assembly time (which is a lot) 
is surely cheaper than Atmel slapping a $0.50 premium on their latest 
design. IIRC a few years ago they were still charging around $5-$10 (at 
volume quantities) for the controller ICs, it's probably cheaper now 
with patents expiring, much higher volumes and more competition etc.

> Interesting. And here I was thinking the metal is expensive. ;-)

It is compared to plastic :-)

> 6. I have no idea WTF "BB+XCR" is.

BB is baseband (the phone/radio bit that nobody actually uses anymore), 
no idea what XCR is.

> 7. I enjoy that "Other" is nearly as expensive as the CPU.

That probably means a whole host of things like the PCB itself, various 
connectors, screws, cables etc.

Post a reply to this message

>> Mind you... I've yet to actually *see* a Raspberry Pi on sale anywhere
>> for the reputed price of $15. :-P For example, Maplin want to charge you

>
> Might be a different model. AFAIK there are four models by now: The
> original A and B models, and the 2nd generation A and B.


various pi's. I think Andrew is looking at those starter kits that 
contain PSUs, USB hubs, cases, SD cards etc, and from Maplin which is 
probably double the price of amazon by default.

Post a reply to this message

On 14/10/2015 11:50 AM, scott wrote:
>>> Mind you... I've yet to actually *see* a Raspberry Pi on sale anywhere
>>> for the reputed price of $15. :-P For example, Maplin want to charge you

>>
>> Might be a different model. AFAIK there are four models by now: The
>> original A and B models, and the 2nd generation A and B.
>

> various pi's. I think Andrew is looking at those starter kits that
> contain PSUs, USB hubs, cases, SD cards etc, and from Maplin which is
> probably double the price of amazon by default.

Yeah, I think their "kit" contains a large hard-back tutorial book, a 
nice enclosure, a butt-load of peripherals and more. It might actually 

don't actually *want* any of that stuff. I just want the device.

Post a reply to this message