wifi is not cheap at the module level and fairly complex at the chip level.
Does it have to be wifi? If not, you could build a wired module that uses cheap RF for the last hop to your device.
Or, you could use a wired connection to a cheap wifi router. Not an elegant solution and needs line power but WifiG routers are really cheap these days - A number of them have bridge mode.
You could use a [WRT54GL and use a simple utility like curl or wget to do the download. Then send it from the router’s internal serial port to your project.
If you’re into fairly hardcore programming, you could try to fit your project into a wireless card’s embedded cpu, like the [prism54 µStumbler.
All this seems insane. I mean there’s a simple chip for everything these days. Why not for WiFi? (listen to me complaining).
I guess what would be good is something like a USB WiFi stick, plus a USB host microcontroller, plus the code to get it to run. I would have thought that there was some open source code somewhere for one of those sticks.
Lantronix WiPort is one of the least expensive WiFi modules for embedded sytems. You can just use it via one of its serial ports, or you can write HTML to run on its web server, or you can write C code to add to it’s system.
There are chips for wifi. Problem is is that its a set of usually two chips [baseband + MAC], both of which are BGAs, and they need all sorts of supporting components + IC’s.
Also, most of those chips are designed for the PCI/USB busses, which aren’t trivially accessible from a low end micro. Connexant has a SPI based chipset, but its really hard to get your hands on chips, let alone docs of the bare chips alone.
In previous work, I’ve tried to get my hands on datasheets / chips for a product and a certain manufacturer [not connexant] was unwilling to sell us chips unless we hit very very large monthly volumes, and wouldn’t give us docs without signing a NDA, and meeting us in person.
what about using some of the wifi CF cards or even the really small wifi SD cards? im sure there must be some documentation on using those for this sort of application somewhere.
CF cards and chips - as said above - the only software you can get to if you’re not a big OEM under NDA is what you can reverse engineer from the Linux drivers. And those are illegible.
So the WiPort and its competitors are the only thing practical. And they’re all well above $100.
If you don’t need megabit speeds, just use an 802.15.4 module. Lots of vendors. $20 and up. Work well. ZigBee needed only for more complex topologies.
A fellow at http://www.wibotics.com/ had done some CF WiFi software, and he also sold WiPort modules for robots, but the market must have been too small and the '15.4 modules are so cheap, he closed shop. His work is available gratis. But this hardware exceeds $50 too.
Open Source 802.11g Wireless Project
USB WiFi Module AssembledCheckout the open source wireless project (http://sourceforge.net/projects/at90usb-zd1211/) that I developed using the AT90USB and ZyDas ZD1211B 802.11g wireless chipset. The total off-the-shelf hardware cost for this project is about $50. Just download the latest release compile it using the AVR GNU or IAR AVR Embedded Workbench compiler and flash to the AT90USBKey (AT90USB1287 Development Board). Connect the ZyDas ZD1211B based USB 802.11g wireless module to the AT90USB with the provided USB cable. I recomend using the Zonet ZEW2501 or Safecom SWMULZ-5400 (see http://zd1211.ath.cx/ for a complete list).
The Lantronics “Matchport” is $88.00 in single piecers. Available from Mouser and Newark. Very cool, but power hungry. Wifi is a high octane guzzler. Bluetooth is better.
RonnyM:
The Lantronics “Matchport” is $88.00 in single piecers. Available from Mouser and Newark. Very cool, but power hungry. Wifi is a high octane guzzler. Bluetooth is better.
Ron
802.15.4 without ZigBee is cheaper yet. And plug-n-play.
AT command set modem emulation from several vendors.
RonnyM:
The Lantronics “Matchport” is $88.00 in single piecers. Available from Mouser and Newark. Very cool, but power hungry. Wifi is a high octane guzzler. Bluetooth is better.