As far as pin count goes, my shield uses the 4 SPI lines, INT0, power and ground. All the other pins will be brought up from the Arduino for use by the end user.
I'd be interested in one if it was in the $40-$60US range.
I want to add my voice to those wanting "stacking" headers.
If you don't want to risk proliferation of models, at least offer one with no headers installed, so people can install their own: it's very likely that people would want to combine the WiFi shield with one or more others carrying sensors or outputs to be read/controlled via WiFi.
Ran
All the pins on the Arduino will be pulled up to the top, so that everybody can put whatever other sensors/dodads/gizmos on top without having to whip out the soldering iron. 
I've created a couple of videos, but so far YouTube has only been able to process one of them, so here it is:
Again, this is only our prototype board we had made. The final board will have:
- female header receptacles on the top side
- male header pins on the bottom to connect directly to the Arduino
- full silkscreen, ground plane, and a nicer color than the drab light green we currently have
As a recap, you'll get 802.11b wireless access, with full support for encryption (WEP, WPA/2, TKIP/AES). The shield will be able to connect to an access point (infrastructure mode) or create it's own network (adhoc mode). You'll be able to put the TCP/IP stack on the Arduino, so it can serve out it's own webpages (like in the videos I've posted). More likely though, I would imagine the biggest use of this would be as some sort of environment sensing device, so it wouldn't necessarily need to serve a webpage, but rather just send back some data from a sensor.
The timeframe is looking like end of April to early May. I hope to have my website and storefront up by then, along with lots of documentation to help users get up and running quickly.
** Edit **
Here's another video showing the Arduino and WiFi shield operating in adhoc mode, using the Arduino to wirelessly control a TV and DVD player. Note that the delay in seeing anything happen is because my TV and DVD player are ancient and take a while to turn on. The delay between the time you hit the button on the iPod and the time it sends the IR code is very small.
Very impressive - tally another sure buy for me.
Sounds very interesting!
I would be interested in buying one of these
But do you have any expected date when the first revision will be available?
I hope to have shields available late April to early May. I wish I could be a little more specific, but I'm at the whim of my supplier who is still getting everything organized.
Great to hear this. I saw your videos on youtube. I am very excited about the web server and the adhoc networking. Question: will their be access to the web server? If it's open hardware, does that make the software in the device open software.
Everything will be open source. There are 3 main components to this project. First is the hardware. Second is the low level 802.11 driver, which will handle things such as the SSID name, security, etc. The third component will be the TCP/IP stack. Currently we've written a very small stack to do the very basic items that we need it to do for testing and creating demos. The hope is that once everything is in the wild, the community will modify and develop as necessary, sharing as they go along. And of course, we'll always be helping everybody as well.
I am definitely interested in one. I have always wondered why wireless devices have not had more interest.
Personally I would be very happy with an 802.11b shield at a reasonable price... even without encryption... I'm really not worried about someone snooping data from my wireless weather station 
and I have several old routers, so I could add an access point for this device and lock it down by mac pretty easily.
count me in!
[quoteI have always wondered why wireless devices have not had more interest.][/quote]
Oh, there's lots of interest. Trouble is, it's a mile wide, but only about $25 deep ;D
The economics conspire to make an 802.11/Ehternet Arduino something of a "novelty" item. If you buy a ready-built Arduino and Ethernet shield, it'll cost you about $80. For about $100, I can buy a Netburner with a Coldfire CPU, half a meg of RAM, and a full-blown TCP/IP stack that can run a lightweight web server and multiple telnet-style connections simultaneously. That means most IP-networked Arduino apps are going to be projects by people who like the challenge of squeezing a lot of function into a limited platform and have the skills to integrate their apps tightly with the partial TCP/IP stack.
I've done a lot of simple serial protocols over the years, but, when it comes to something as complex as IP, I really prefer to just open a socket, and have the driver call me back when it's put together a whole packet for me, so I can concentrate on making the servos whirl and the lights blink.
Something that might be really interesting is one of the new Mega boards, with a Wiznet chip and Ethernet jack on it instead of an FTDI chip and a USB port.
Ran
But with that 100$ chip, what would you then be able to do more, than just with the 80$?
Isn't it possible to make the 80$ chip working as a webserver? But would that require more space and power from the ATMega chip (processor)
Yes, I'm definitely interested! Can we sign up anywhere for an email list?
Hi,
A WiFi shield for Arduino is an excellent idea.
I really look forward to getting one when it comes out.
One recommendation: make sure there is adequate documentation, sample code and/or application notes. There are too many devices out there that are difficult to use because they are poorly documented or have buggy code samples.
Is there an update on when the Wi-Fi sheild might be available?
This is a great idea. I think 802.11G/N/A would be a waste of time. The Arduino can't push that much data (and why would you need to?).
I'm impressed you managed to provide WPA/WEP. That has to add some heavy overhead!.
If I'm totally honest, cost will be a factor though. Getting the price down will be the major hurdle. I'd consider making a secondary adapter so other enthusiats can use the module (outside of arduino), that should open up your market a little more and drive costs down (ec of sca)
Thanks for all the interest! I am targeting May 1st as the availability date of the wifi shield. I am currently putting together my first batch of about 65 shields. I'm also working to get the driver code simplified so that it's easier to use, as well as documenting it. And I have other hurdles I'm battling (website stuff, shopping cart, legal papers with the state, etc). Needless to say, I've never been this busy in my life, but at least I can say that I'm working on something that is fun and interesting to me! (even if my wife doesn't share this enthusiasm) ;D
Here are some pics of the final product:
The shield will bring up all the pins from the Arduino (a true plug-n-play shield solution). On the shield, there's an LED to indicate your connected (you can disable this via the jumper in the event you need the digital I/O for something else). There's also a jumper switch to choose between using INT0 and digital pin 8. INT0 is the preferred interrupt pin needed for the wireless connection, but we noticed that some of the LED shields use pins 2 and 3 for connection, so we provided an out in the event somebody wants to put a touchscreen shield on top. Lastly, the reset button has been propagated up so that it's easier to use.
Again, a brief review of some of the highlights of the WiFi:
- 802.11b access (1 and 2 mbps)
- infrastructure and adhoc mode
- WEP (64-bit, 128-bit), WPA/WPA2
- can fit into a ATMEGA168 (can't remember the approximate size off the top of my head) with room to spare for your own program
- currently, payload will have to be limited to 500 bytes or less (this is mostly due to the ATMEGA168's RAM size), however I'm experimenting with breaking up packets (this may come in a future release of code)
- SPI interface with 1 pin for interrupt
I'll do a couple more demo videos soon (especially showing the new final hardware), but for now, please refer to my previous demo videos to get a feel of what you could do:
So I know the million dollar question is "how much is it?" After crunching the numbers, it looks like pricing will start at $55, with a 10% coupon for the first batch or orders I receive (65 shields in the first batch).
I really hope that others will find a use for the shield. I have ideas for other projects coming down the pipe, so this shield won't be the only thing to come out of my "lab."
I'm having issues getting my email notifier working in my shopping cart (http://asynclabs.com), so if you are interested when it is available, please shoot me an email at asynclabs@asynclabs.com, and I'll send out an email when the shield is ready to be purchased.
Brad
Great news! A couple of questions. Will it be necessary to run the web server or can you drop that and just use the tcp/ip stack? Granted communicating via a web server might be easier.
Is it possible to add an external antenna?
Does it come in kit form (for a cheaper price)?
For the first batch, everything will be preassembled. We want to guarantee that the first users will have a fully-tested, out of the box working solution.
Unfortunately, the WiFi module itself is not beginner friendly in the soldering department, so even if we did offer a kit, we might offer 2 kits, one with the WiFi module soldered on (end user can put the rest of the parts on) and a full blow kit with all the parts and a really big flashing disclaimer that you better be skilled at soldering and that we can't be responsible for dead parts. :o
For the other question, I assume that when you say "just use the tcp/ip stack", you are basically referring to a client mode where your Arduino/WiShield just responds back with bits of data. It doesn't have a webpage to show the data, but merely just gives data back to somebody else (say a PC on your network that is collecting information from different sensors). The answer to that is yes, you can do that too. I showed the webserver demos mostly because those give a quicker visual indication of what is going on.
For the external antenna, the answer is yes and no. For this first batch of parts, they are configured to use the PCB antenna that is on the module. They can be converted to use an external antenna (not easy though). I'll need to get a list of external antennas that will work. Note that if you convert the module to use external antenna from internal, then the FCC certification of the module is thrown out the window (which shouldn't matter to most of us, since most people aren't going to use the shield in a production, commercial product, yet). If the FCC certification is really important to you, then there is an option for me to get the modules preset for external antenna from the factory of the supplier. All this information will be detailed on my wiki on my website once I start populating all the documentation.