DIY with a low cost box and LCD

[lilltroll]

I took apart a digital photo-frame.
No glue, it's all screwed and it uses standard connectivity, like Molex.
The case comes with a LCD, DC-in, SD card, USB connector & buttons, and you could easily put your own card there instead, and there is place in the plastic to drill more holes.

Sometimes they sell out obsolete frames for very low price. Even the original sticker with the serial-number of the LCD was left so I could find info about it on internet.

Have anyone considered to use a photoframe for a custom made card?
Some of them looks more like a small (plastic) iPad not having a very large extra plastic boarder around the LCD.

[Bianco]

If you plan to use your own board you need to drive the LCD. Many of them use LVDS on a high frequency so you problably need a FPGA. Most of these photoframes use a ARM9/11 or MIPS and are hackable. Also a lot of them use a custom ASIC with a less known processor on it to save costs which is harder to hack. Once you have access to the (Linux) OS on it you can do whatever you want with it and it saves the time of making your own board.

[lilltroll]

This one uses the Multi Media SPMF-2800 processor, which I believe is a SoC ASIC from Sunplus.

I haven't read the data-sheet for the LCD yet, but I will check out the Interface signal.

[octal]

Sometimes ago I used a mini2440 (I bought it about 65 euro including LCD).
Friendly ARM produces this board since more than 2 years, ant the price is not that expensive

http://www.friendlyarm.net/products/mini2440?lang=en

http://cgi.ebay.co.uk/mini2440-S3C2440- ... 2eaeb47694

I got mine working under embedded Linux, but you can use it also under WinCE (if you need but be careful to the license if you entend it for commercial purpose) or you can simply use it without any OS (the C drivers are provided).

The LCD hardware interface is managed directly by the samsung MCU and it's damn fast ;)


Regards

[Bianco]

Sometimes ago I used a mini2440 (I bought it about 65 euro including LCD).
Friendly ARM produces this board since more than 2 years, ant the price is not that expensive

http://www.friendlyarm.net/products/mini2440?lang=en

http://cgi.ebay.co.uk/mini2440-S3C2440- ... 2eaeb47694

I got mine working under embedded Linux, but you can use it also under WinCE (if you need but be careful to the license if you entend it for commercial purpose) or you can simply use it without any OS (the C drivers are provided).

The LCD hardware interface is managed directly by the samsung MCU and it's damn fast ;)


Regards

I have two of them here collecting dust.. I should do something with them some day ;)
Ebay is the best place to get them.

[Heater]

XMOS has a competitor in the multi-core micro-controller market, the Propeller chip from Parallax Inc. Replacing a key chain digital photo frames processor with a Propeller chip has been done. Including the addition of:

3-axis accelerometer,
USB chip,
real time clock (RTC),
buzzer/speaker,
flash memory,
battery.

Therefore I assume it can be done with an XMOS device. Anyway you might get some hints about how to proceed from that implementation
http://forums.parallax.com/showthread.p ... -shipping!

[lilltroll]

Yes I found the propeller project. I also dismounted the frame. The backlight is a LEDlist with passive light-diffractor. No tricky Cold Cathode Fluorescent Lamps with Hi Voltage.

The Thin-film transistor seems to be connected via an active matrix e.g. each tranasistor gate is controlled by an Voltage that is about 0.4-3.4 V which modulates the intesisty via 3 RGB pins.

The active matrix is controlled by a HSYNC and VSYNC pulse to reduce the amount of connections from n+m to just a few lines. I also found a datasheet of the signal timing to the LCD.

LVDS, no we are not talking 1 m cable > 300 MHz bandwith here, its around 4 cm. Somewhere the signal must be translated to the voltage driving the gates - so I wouldn't consider it impossible.

And I do not want to re-engineer the Photo-frame. It's more to have a debug screen at a low price in an already existing case, where you can mount an rectangular PCB card. I actually have access to 3D printers, but that is a lot of work and the plastic is fragile or doesn't like the UV from the sun, so you have to paint it. Using a lookup-table for a font wow - 8 pixels - generating text does use very little memory and CPU load (No bit-baning).

They have even made a lot of extra skrew holes for different size of cards. Making new plastic tools is a large cost, so I guess they reuse the backplate to many products, just chaining the front making "a new product". Even the buttons is a cassette by its own.

Buying a 16x2 ASCII LCD and a ugly box is the same price or higher compared to reusing a photo-frame.

[octal]

And I do not want to re-engineer the Photo-frame. It's more to have a debug screen at a low price in an already existing case, where you can mount an rectangular PCB card

If it's just for debug purpose, I think that a better solution is to join the xvig group and try to develop a VGA text (or graphics) mode driver. You can then use a true VGA monitor for debug. Most developers have two screens on their desks, and most screens have two inputs, you can simply use your XMOS device to send data directly to one of the displays. The second reason, is that VGA displays are not that expensive these days, used disp cost less than 30 euro and have nice diagonal 15" ;) and have enought space inside to house your additionnal board if needed :).