Dream System for Self Tracking - Proposed Architecture

the central data system

what i would like (if i put my dreams out there, they often come true! -JBL)  is a system with the following properties:

• a website/server that can receive formalized data packets about me (and others), and put them into a database.  some of these packets would likely be generated by devices such as little webpods attached to RS-232 scales.  others could just be sent by email with a specific subject line, etc.
• use of simple protocols like GET and POST so that small devices can send data to it
  
• tools connected to this database to allow me to visualize and analyze the data.  initially just starting with, say, a simple graphing tool, like show variable x against time
• means of downloading my data in some standard format like XML and/or CSV
• ability to designate data as private (the default) or share it with the group, or the public
  
• a sense of security that the data gets backed up, and that it won't get hacked and have my wife's menstrual cycle get put on my wikipedia page

webpod proposal

as an adjunct to the central data system above: a small, appliance-like device that can send a formalized packet based on various kinds of input.  for instance, a little box with an RS-232 input and wifi inside.  a simple DHCP-based autoconnect to the wifi access point, and knowledge about how to contact the central data system.  using this interface, i want to give it some basic rules about how to interact with the RS-232 port, and how to translate the info from that port into packets sent to the central data system.

here are some strawman specs in summary:

• wifi.  this is so that it can be anywhere in your house, not where there happens to be a computer.  bluetooth doesn't have the range to get from the upstairs master bathroom to the downstairs office at the other end of the house.  the simplest standard i have seen forming for getting wifi devices onto secured networks is to put the network name/password on a USB thumb drive in a text file and just plut it into a USB port.  if the LED turns green, all is well, etc.
  
• RS-232.  needed to connect to nice scales for sure, and possibly other gear as well (blood pressure monitors?)
• smart.  since it's a pain to learn to use tiny, impoverished UIs, and expensive and boring to design and build them; it would be better to have a faceless module that we talk with via the web.
• cheap, small, quiet, reliable.  to get ourselves to uses these things, they have to be all over the house and perhaps even office -- wherever we are when it's most convenient to collect data.

is there something that already exists that will work for us?  something without a fan?  maybe an eval board for some ARM microprocessor? 

some candidate hardware platforms:

• gumstix motherboard ($109) with wifi module ($79),
• lantronix wiport ($120). built-in wifi and serial. 
  

• basic stamps? other vendors?
  

iphone app proposal