Cheap 1" GLCDs for small displays and LCD buttons

[cheater]

Hey guys,

I was wondering about graphic LCD buttons for cheap today, and was searching around for sources of small LCDs.

I found out old Nokia cellulars (i.e. 3310 and so on) had great monochromatic LCDs that can be taken out and used easily. They use the pcd8544 controller.

The great thing is that a WORKING nokia 3310 and equivalents cost ~5 USD here in Poland. I haven't bothered to search around, but I bet you could get that stuff much cheaper in "bargain lots" - USUALLY the LCD does work in phones otherwise broken (which are mostly "dropped" or "drowned" phones), unless it has a huge spot of liquid crystal on it - then you know it's broken :)

Here are two sites which give a lot of info on these LCDs:

• http://serdisplib.sourceforge.net/ser/pcd8544.html - identifying and dismantling LCDs in nokia phones. Some basic circuits and app notes of a C driver.
  
• http://www.selbing.com/_jakob/electronics/nokia.htm - some more info.
  

So how do you use that for a button?

The LCD is too big to fit inside a button.

But you can:

1. take a small round button - a kind that would not have a shaft, but rather, would be supported on spokes that are on its sides. Think of an empty cylinder standing upright. On the bottom edge, it has a spoke going left and another one going right. On the left, it is supported on something that creates a hinge. On the right, it rests on a tact switch. This creates a lever which is supported by the left spoke and presses on the tact switch on the right - while creating no obstruction of visibility through the inside of the button. Perhaps you would want to use two of those "spokes" on the left, to create a kind of tripod (for stability)

2. cut the cap off (there's no cap if you're using a piece of PCV or metal pipe :) )

3. now you can see the graphic on the LCD through the created cylinder.

4. you can put a lens on the top of the cylinder to have the image "crawl on top" of it. I'm not an optician - but you can use a lens so the image appears to be on the top of the lenses surface, instead of being deep inside the button.

5. Maybe, instead of a cylinder, you can use a "thick" lens which would be a cylindrical lens "glued together" with a spheric lens. It would look roughly like this: (_|  with the spherical part being the one the user touches.

This method means the spacing of this kind of button is limited by the size of the hinged assembly. You can probably use two of those "buttons" per one Nokia GLCD.

Has anyone ever tried looking at watch GLCDs? those could also work well... and you even get a lens with them in the watch, which could be used as a button: Just glue the lens on top of the LCD and glue the "hinge" assembly on the bottom of the LCD.

The Nokias come with lenses as well... but... what use would such a huge 1-inch-diameter button be?

I hope this stuff works well for some crazy heads here.

[stryd_one]

Hey cheater you know the PCD8544 is already supported by MIDIbox?

[dj3nk]

;) His idea was to build a button of it. I think he knows that its supported

[audiocommander]

what use would such a huge 1-inch-diameter button be?

hmm, one could mount it on top of 4 tiny switches. so you could have kind of a menu selection / directional button.

or even cooler: using it with a tilt sensor  8)

(ohh, I have too less time for all this)  ;D

Michael

[dj3nk]

Yeah thats cool ! 4 buttons ^^ havent thought of that

[cheater]

Hey cheater you know the PCD8544 is already supported by MIDIbox?

Sorry. No idea at all. I'm just a newb, posting my crazy researches :P

The idea with the directional button is nice. Do you guys know the assembly of a 16-bit-console D-Pad? You could easily do that, with one tact switch (or even a "rubber switch") being in each of the corners. You could even add colored leds in each corner, so you get some kind of feedback with the color. That would require the lens to be split up in 4 and the parts to be optically decoupled (with some black or white paint on the touching faces or something like that).

[audiocommander]

yeah, or think of just a simple bar animation that may sweep to left or to the right, or in case of a tilt-sensor some animated fluid. :)

nice ideas...

[cheater]

I think those things could work as per-track displays on something like an LC, too.

Maybe you could pre-define graphical icons for certain track names in the LC.

Like, syn* would give you a synth icon etc...

[cheater]

How about this:

A scope for the synths. Or maybe a frequency analyzer.

[dj3nk]

prog it :) would be a nice idea

[cheater]

prog it :) would be a nice idea

You're talking to someone who has no idea how to program :)

Hardware-wise, I think the PIC's internal ADC would be more than suitable for this task. And those ADCs are unused in the SID pics... am I right?

[dj3nk]

in the SID pic ? you mean the adc of the 18f isnt used from the sid software, right?  Well, no, it isnt. But is it possible to drive a LCD over the adc ? im not very known @ picprogramming yet. buti think not because the adc just converts incoming analog voltages to digital.

[stryd_one]

that's a freakin cool idea.

DIY PIC18F Digital Oscilloscope

There's a starter. Obviously you'd have to cut this down a LOT

[cheater]

in the SID pic ? you mean the adc of the 18f isnt used from the sid software, right?  Well, no, it isnt. But is it possible to drive a LCD over the adc ? im not very known @ picprogramming yet. buti think not because the adc just converts incoming analog voltages to digital.

What I meant is that you need an ADC to sample the analog output of the sid into the digital domain to show that stuff on a digital LCD.

I think it would be enough if you had the `scope scale the scan frequency so the waveform is locked. I mean, with such a small resolution, you wouldn't be able to do a lot more than building a gizmo ANYWAYS :p

[dj3nk]

omg ! thats kewl ! now I understand what you meant. !