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Low cost, Power over Ethernet (PoE) touchscreen display driver

Need: Two things are happening - flat-panel display component costs are going lower, and there is an upward trend towards ubiquitous displays / ubiquitous computing. (multi-purpose display panels and interactive information available everywhere - not just attached to traditional computers)

Currently there are three primary ways to drive a remote display (think home/building automation panel, building directory display, even those framed "photo viewing" devices, etc...)

Drive each display with a remote computer: This allows for the furthest content distribution distance and fast response, but adds several hundred dollars to each endpoint and creates a software maintenance/upgrade liability. This cost is getting harder to justify when some small flat-panel components now sell for around $35. (QVGA)

Drive each display with VGA/DVI signal:This usually creates a severe distance limitation (less than 100' from host computer) and potential signal degradation. Interactivity is provided by running a seperate serial interface for each touchscreen.

Create and run the GUI on embedded hardware (ARM/XScale/Coldfire): This can create a low cost hardware driver, but requires that you "roll your own" GUI (pixel by painful pixel). This is a time consuming and expensive process with usually less than attractive results. (even with embedded GUI libraries)

NEXT PAGE: Building the first prototypes (with photos)

The Solution: A small, lightweight interface that simply connects to standard ethernet and has just enough hardware to decode/encode standard remote display protocol frames (eg: VNC / Windows Remote Desktop) and send the results to a display driver chip. For smaller screens, or future low-power OLED screens, the entire device could be powered from the ethernet interface via power-over-ethernet (PoE). This eliminates the need for seperate power drops at each end-point in the building.

Several interactive screens can be distributed throughout a commerical building or house by using ethernet switches/hubs to extend the network.

Using a standard display protocol interface would allow programmers to write interactive display and control applications quickly using rapid development languages like Java, and Visual Studio.NET.

Using Java for example, one host computer can serve multiple interactive Swing or AWT user interfaces through VNC by extending classes in the LGPL project VNCj (Latest Java 1.5 / VNCj code update)

Goals:
  • Use standard protocols
  • Use a standard display driver
  • Make the device a Power-over-ethernet (PoE) endpoint to eliminate the need for additional power drops in retrofit installations.
  • Make the device as low cost as possible - potentially making a sub-$100, wall mount, interactive flatpanel display a reality.
  • light goal: Making small versions of the complete assembly (3" screen and hardware driver) size compatible to an existing single or dual-gang wallbox.



    • Protoype Vision: QVGA (3" touchscreen) driven by lightweight power-over-ethernet VNC driver. Only required connection is an ethernet cable, so no seperate power feeds are required at each endpoint. (This is a big deal in retrofit installations)
    Any size screen and resolution should work


    Target Product Specifications: (Major components)

  • Atmel ARM920T SoC CPU
  • Epson S1D13506 LCD/CRT/TV Controller - Supports up to 800x600
  • Texas Instruments TPS238x IEEE 802.3af endpoint power manager
  • 4 Mb Flash / 16 Mb SDRAM
  • uC/OS-II RTOS and licensed TCP stack


    • Building the first prototypes (with photos)