JES

Gregory Alan Bolcer gbolcer@endeavors.com
Sat, 02 Mar 2002 10:02:34 -0800


Anurag Narayan wrote:
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> Hi,
>     I am absolutely new to this embedded system concept.I have installed JES on my windows NT and now I have no idea wha to do with it now.Suppose I want to control  my TV with it what else do I need and how will I make this JE server interact with my TV.Please help me to atleast get started.
> Regards,
> Anurag Narayan

Unfortunately the answer is too complicated to dump
into one email.


JES doesn't do anything by itself.  JES is nothing more than
an HTTP server that serves as an (external) gateway for other
home networks and protocols such as X.10, Havi, IrDA, or even UPnP. 
JES's architecture relies on specific protocol translation
modules that translate an HTTP command into a protocol
specific message off to a device on a hardwire or
non-networked channel.  

A separate but more elegant approach is what UPnP is 
proposing and that is to run the micro-HTTP server on the 
actual devices, the most common example they give is the VCR.  

To get started, it all depends what you want to do.  If
you want to be able to remotely turn on and off your VCR,
you need to order an X.10 module, plug your VCR into the 
X.10 module, register it's ID tag with your server, put
an X.10 PCI card into your NT machine, programatically
write the JNI binding to the interfaces, configure the
servlet setup, write a servelet to call the JNI interfaces
and voila! You can turn on and off your VCR which isn't that
useful as you can just set your VCR to start and stop anyways
if you are clever enough or have bought a VCR+ controller. 

To do something more complicated, you'll need to figure out
a control line into your VCR.  As most VCRs don't give you the
specifications, you typically can use the same channel as the
remote control does.  HAVi is the best mechanism.  Vivid Logic
has some good Java examples and a licensable SDK for programming
some of these capable devices. 
http://www.vividlogic.com/hbx/pvr.html

More interesting is the ability to turn your PC into a VCR.
This can be done via the X.10 controller, a PC video card that
supports media input/output and some clever programming.  You
can have it such that you use your remote broadband connection
to talk to your computer (you'll need security) to flip on
the cable/television over X.10, use the software tuner that
comes with the video card, and then start writing to disk.  Typically
you'll need about 10Meg/minute as it's hard to do on the fly
compression unless you've done some more clever programming. 

The neat part is if you add JSP into your Web server.  Using
JSP and one of the WML toolkits from Nokia or Openwave you
can write a set of WAP pages that let you control the same
thing.  The scenario being that you take your wap phone with
you more places than a booted computer with a network connection. 

Anyways, good luck getting started. 

Greg