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#147394 - 06/03/2003 19:00 Backlit Display
mvigneau
member

Registered: 12/08/2002
Posts: 179
Loc: Manchester, NH
This question has probably been asked already, but I couldnt' find it when I did a search.

I was wondering if there was a way to get a Backlit Display working in place of the current 128x32 Display that comes with the RioCar Empeg? I have a problem seeing the display in direct sunlight and would like to use a backlit display.

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#147395 - 06/03/2003 19:13 Re: Backlit Display [Re: mvigneau]
suomi35
enthusiast

Registered: 16/02/2002
Posts: 290
Loc: Denver, CO
That's an interesting thought. I guess you'd need a clear lens with that. I have seen pics on riocar.org of an lcd being used with the empeg.
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-Jason

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#147396 - 06/03/2003 19:19 Re: Backlit Display [Re: suomi35]
suomi35
enthusiast

Registered: 16/02/2002
Posts: 290
Loc: Denver, CO
Here is the pic
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-Jason

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#147397 - 06/03/2003 20:55 Re: Backlit Display [Re: mvigneau]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31549
Loc: Seattle, WA
I have a problem seeing the display in direct sunlight
Just to make sure, you've read this, right?
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Tony Fabris

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#147398 - 06/03/2003 22:20 Re: Backlit Display [Re: tfabris]
TheAmigo
enthusiast

Registered: 14/09/2000
Posts: 363
Interesting (just read the FAQ entry).

I've always thought my display was too dim (blue Mk2a) in the daylight. I can read it on a cloudy day, but not on a sunny day (even without being in direct sunlight).

I just checked to see that my dimmer option was at 100% and it was. BUT when I turned the knob to the right, it got a lot brighter! So I played with the setting for a bit... The progress bar and number always do the right thing, but the actual brightness doesn't.

As I move to the left from 100%, the display reads 90, 80, 70... just like you'd expect but the brightness seems to "zig-zag" its way down... some ticks make it brighter and some make it dimmer (e.g. 30% is notably brighter than 40%).

If I keep ticking slowly to the right past 100%, it alternates between medium and bright even though the number stays at 100%.

I'm running 2.0b11 with HiJack 300. Have there been any changes to the dimmer code since then?
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--The Amigo

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#147399 - 07/03/2003 00:29 Re: Backlit Display [Re: suomi35]
jarob10
enthusiast

Registered: 07/01/2002
Posts: 274
Loc: Stockport, UK
Did this use the serial interace ?
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#147400 - 07/03/2003 01:22 Re: Backlit Display [Re: TheAmigo]
matthew_k
pooh-bah

Registered: 12/02/2002
Posts: 2298
Loc: Berkeley, California
Dimmer Fix. It's a very common bug. 100% should be readable in all but direct sunlight, unless you're cursed with a convertible.

Matthew

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#147401 - 07/03/2003 11:41 Re: Backlit Display [Re: jarob10]
mvigneau
member

Registered: 12/08/2002
Posts: 179
Loc: Manchester, NH
How would you use the serial interface to run a backlit LCD?

Is there an easy way to get it setup?

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#147402 - 07/03/2003 11:58 Re: Backlit Display [Re: mvigneau]
Chimaera
enthusiast

Registered: 10/09/2002
Posts: 285
Loc: DFW Area, Texas, US
check out this thread, while he is looking at using a serial VFD there is nothing to stop you using an LCD instead (infact I think that is even mentioned in the thread)
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Mark. [blue]MKI, MKII & MKIIa, all Blue, and all Mine![/blue]

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#147403 - 07/03/2003 12:24 Re: Backlit Display [Re: mvigneau]
V99
member

Registered: 12/01/2002
Posts: 192
Loc: Phoenix, AZ
There's no software released to do it yet, but Hugo has whatever he used to get pictures of his tiny remote display, I'm working on code for my remote display, foxtrox_xray might be working on his for text output, etc.

If you can find a serial 128x32+ LCD with bitmap drawing routines (or just text if you want to do what foxtrot is doing) it would be easy to adapt any software to it's specific command set/peculiarities.

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#147404 - 07/03/2003 12:37 Re: Backlit Display [Re: Chimaera]
rtundo
addict

Registered: 27/02/2001
Posts: 569
Loc: Albany, NY
You might also think about using a second VFD mounted in front of you where the sun doesn't affect it. Near the gauges, etc. I'll probably do something similar so I don't have to keep looking down at my center console to read the empeg screen.

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#147405 - 07/03/2003 13:39 Re: Backlit Display [Re: V99]
foxtrot_xray
addict

Registered: 03/03/2002
Posts: 687
Loc: Atlanta, Georgia

There's no software released to do it yet, but Hugo has whatever he used to get pictures of his tiny remote display, I'm working on code for my remote display, foxtrox_xray might be working on his for text output, etc.

Actually, my little program will be doing both. With some help from some folks, I have successfully got a way to read the empeg_display.raw file, parse it so I have a byte-per-pixel.. (Hey, I was pleased about that. Learned a few new C tricks.)
All I got left, for basic functionality, is to loop and do a compare for what changed since the last 'read'.. Then go thru that and optimize the commands to send to the display.

Me.
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Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper

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#147406 - 08/03/2003 01:43 Re: Backlit Display [Re: foxtrot_xray]
V99
member

Registered: 12/01/2002
Posts: 192
Loc: Phoenix, AZ
I've been thinking about algorithms to optimize what's sent over the serial while not paying attention in lectures.. On the K610A your options are somewhat limited by the command set; The 3000 and 7000-series have more tools available.

To figure out what's changed, you XOR the previous frame with the current one.

The simplest thing to do is just figure out the bounding rectangle of what's changed and draw just that as a bitmap:

Changed = OldFrame XOR NewFrame

Left = 128, Right = 0, Top = 32, Bottom = 0
NumChanged = 0

for ( y = 1 .. 32) {
for ( x = 1 .. 128 ) {
if ( Changed[x][y] == 1 ) { //Changed would be a 1 dimensional array, but for simplicity..
NumChanged++
if ( x < Left ) Left = x
if ( x > Right ) Right = x
if ( y < Top ) Top = y
if ( y > Bottom) Bottom = y
}
}
}

if (Right >= Left && Bottom >= Top)
draw(NewFrame,Left,Top,Right-Left+1,Bottom-Top+1) // bitmap, starting_x, starting_y, width, height
This works well when small areas of the screen change, but if only the top-left and bottom-right pixels change you end up drawing all 128x32 of them when only 2 needed to be. So you could split the screen up into smaller rectangles and do the cropping/drawing thing on each one individually at small overhead (a few extra bytes per draw) and potential large gain.

You could also calculate for each update rectangle whether it would be less bytes to just move the cursor and set/clear each of the changed pixels. If it took say 9 bytes to move the cursor and update one pixel, and a bitmap draw took 7+data bytes, then you'd want to draw by pixel if 9*NumChanged < 7+(Bottom-Top+1)*(Right-Left+1)/8.

If you want to get more complex, you could look at the change and try to identify the optimal configuration of rectangles to draw, or rectangles of solid image that you can draw with an area/box fill for only a few bytes. This is where peeking at VNC code to figure out how they figure out what the update rectangles should be.. no efficient algorithm comes to mind immediately.

On the 3000 and 7000-series displays with more advanced software in them you can come up with all kinds of tricks using scrolling ability and other cool features they have. The K610A doesn't support XOR-mode drawing, so you have to send the actual pixel values instead of "change these pixels". With XOR drawing you could use the line/box/etc drawing routines to toggle large groups of pixels at a time for virtually no serial transfer (5-10 bytes to issue a draw this from x1,y1 to x2,y2). This stuff might be particularly important if you're using the 256x64 3190 model, which has a lame 38,400 connection to update 4x the pixels. The 140x32 7000-series one is 115,200bps so you can get almost 30fps just blindly blitting the whole screen every frame.

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#147407 - 10/03/2003 21:54 Re: Backlit Display [Re: matthew_k]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31549
Loc: Seattle, WA
Matthew, you've made me realize that the FAQ entry for "can't read display in daylight" doesn't directly link the random-dimmer-values entry, because I considered them to be two separate issues. I'll make that correction now, thanks.
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Tony Fabris

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#147408 - 24/03/2003 20:34 Re: Backlit Display [Re: V99]
mvigneau
member

Registered: 12/08/2002
Posts: 179
Loc: Manchester, NH
Is there a way to get Hugo's code and the model of the tiny remote display that he used to get his working. That is exactly what I want to do so that I can read it in Direct Sunlight.

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#147409 - 25/03/2003 19:47 Re: Backlit Display [Re: mvigneau]
V99
member

Registered: 12/01/2002
Posts: 192
Loc: Phoenix, AZ
The tiny one is the Noritake GW128x32C-K610A-06. You need other hardware to do level conversion and stuff, see foxtrot's thread.

It's 19.2kbps and 1-bit, enough for ~4fps if you're just drawing the whole display every time. To get faster or grayscale Hugo was taking about basically replace the circuitry that drives it and just using the glass itself.

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#147410 - 08/04/2003 11:59 Re: Backlit Display [Re: mvigneau]
fede
journeyman

Registered: 31/01/2002
Posts: 89
Loc: Texas
Any chance of something like this becoming a kit for those of us who are not so electronically talented?
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#147411 - 08/04/2003 15:03 Re: Backlit Display [Re: fede]
foxtrot_xray
addict

Registered: 03/03/2002
Posts: 687
Loc: Atlanta, Georgia

Any chance of something like this becoming a kit for those of us who are not so electronically talented?

My ultimate goal, when I finish the PCB for the remote display is to have a small kit - either one you solder (like the Tuner Kit, but much much less complicated. - but it may be a while off, just because of my free-time limits...
(I already steal time from work to play with the small program to write to the screen.. Just don't tell anyone..)

Me.
_________________________
Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper

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