This article in German describes how to use a cheap (30 Euro) digital picture frame as 'industrial display', those displays are usually very expensive.
As a short translation: the way it is done is disconnect the analog R, G, and B signals used with these TFTs, and leave the scanning signals to the display intact. Then sync the FPGA to the scanning signals. Fun fun fun, I still may have a display like that laying about :-)
My own idea is now that cheap (100 Euro) portable DVB-T receivers with similar display are available, will somebody please do the DVB-T modulator in FPGA? Then changing hardware on these displays in no longer needed, and you have 25 fps.
On a sunny day (Tue, 29 Jun 2010 20:39:39 GMT) it happened firstname.lastname@example.org (Nico Coesel) wrote in :
Interesting site. The problem with that is, that after you add shipping costs, order it, it lands in the NL customs, you have to pay import duties too, for a 10 inch LCD (the smallest new one I could find on their site), that would make about 20 Euro + 20 Euro shipping + import duty + waiting.
I can drive to / order from and pick up a 7 inch for 40 Euro now.
I think not. I have enough experience with jpeg and mpeg compression to know that stills or almost stills get no loss in fine details. I have experimented with that, What you call 'loss of detail' only happens when things move. In displaying a meter panel or some waveform it comes out 100 %. Mpeg2 being just jpeg with interpolated frames, try it with a jpg of a sine wave waveform with some small font text, and see how incredibly far you can reduce quality before it becomes a problem. You can use 'xv' in Linux to save ever more compressed images of the same waveform to try.
Looking for DVB-T modulator there exists many cores, and many complete solutions, but almost nobody gives prices, and the ones that do ask > 1000 Euro... I could program one, but hell do I have to program EVERYTHING myself? And I would have to fork out for the specs... But I found this:
Those compression artifacts in broadcast TV are due to trying to insert too many TV-programs into a single 8 MHz multiplex (typically
22 Mbit/s net).
In a CCTV application, the whole 8 MHz multiplex could be used for a single stream. A less robust error correction would suffice, increasing the net payload to close to 30 Mbit/s. Of course, the receiver might not be able to handle that high bit rates.
The compression artifacts are going to be rare, when sufficient bandwidth is available.
On a sunny day (Wed, 30 Jun 2010 15:53:37 GMT) it happened email@example.com (Nico Coesel) wrote in :
I will look again.
up a 7 inch for 40 Euro now.
OK, anyways, I went over to V&D and got myself an 8 inch Kodak for about 49 . This one has a touch interface, not on the screen itself, but on the border so to speak. I bought it because the quality is absolutely stunning, very bright too, colors are correct. The interface is slow, maybe a 4MHz Z80??? hehe. Tried to open it, removed some screws, but so far I have not been able to open it, and I do not want to demolish it, now it is on my desk displaying full earth rising as seen from moon by that Japanese spacecraft, Maybe I will hang it on the wall and go for the DVB-T modulator.. have not decided yet. Of course the resolution is much less then 680x480, but people are so used to rotten de-interlaced B quality low bitrate movies played on HD capable sets... I think this will do for many things.
Well, if you use it for example as a scope, and grab a waveform, then you have a still picture. One feature I thought of for the digital scope is to have it beep every time it skips (loses) a trigger :-) LOL I mean if the waveform, or whatever you want to display, MOVES, then it is less sharp anyways, this is the whole idea of MPEG compression, moving things need not be so sharp displayed, so that reduces bandwidth, needs less bitrate. As somebody already pointed out you can get to max bitrate if you 'own' the channel. MPEG2 is really really good above about 6000 kbps.
seems crazy to go go all the way through dvb-t, I'm sure there's lots of display available with vga or hdmi or just get a replacement panel for a laptop, most have a display port interface which should be easy enough with an FPGA
I did, and some are ven more expensive (8 inch) then the bigger ones.
And maybe you like this, the model I bought for 49 ¤ is a Kodak P820. Now I know why it looks so good, as the specs say: Image file formats JPEG, EXIF Dimensions 25.8 × 18.1 × 3.3 cm Weight 577 g Display size 20.3 cm (8 inch) diagonal Display area 17.7 x 9.9 cm Display resolution 800 × 480 pixels
On a sunny day (Thu, 01 Jul 2010 20:49:40 GMT) it happened firstname.lastname@example.org (Nico Coesel) wrote in :
And I Wonder... I have not opened it up tyet, but followed some old hacker tactic, downloaded the 'firmware update' (not really needed as it is the same version as on the device). This to see wha tteh code looks like. So, in Linux, I typed the magic command: strings Kodak_FW_V82c.img Now that became very interesting, especially these few text blobs that came out:
bug in kprintf: bad bas"xz ATMEL AT49BV163A Athena_OTG_controller0 /dev/usb video mpeg2decL > perhaps
On a sunny day (Sat, 03 Jul 2010 14:21:49 GMT) it happened email@example.com (Nico Coesel) wrote in :
Tried to open it again today, no luck. Do not want to damage it. But did some more research, I think they are ATMEL users, and for the touch interface I think perhaps they are using AT42QT2160_DS.pdf. That is a capacitive touch sensor with i2c interface and also a slider bar. I tested for capacitive, and as it also works with a piece of paper in between it must be. Bit later I will hold a scope probe in front and test for the waveforms of that chip :-) ATMEL even mentions 'for photo frames' on their site.
To do that one needs to be very very sure. And I am not the police. I have no other interest then to use it.. The idea of writing your own firmware, as is done for example with the Canon cameras 'chdk' releases, is an interesting one, as then you do not have to flash but can run your own firmware from RAM. As to the FLASH size, the Linksys WAP54G also has 2 MB IIRC and runs a nice Linux (on MIPS), I even have a Linux on a 128 MB stick (very old).
Maybe I will discover more about this thing without opening it...