Embedded device spawning a wireless network - which module...?

Generally, a wireless protocol 'standard' (ie: 802.11, Bluetooth) provides a means to allow for other devices to connect.

For a proprietary designed protocol, a device must support that protocol to connect into it.

en.wikipedia.org/.../Wi-Fi
en.wikipedia.org/.../Bluetooth

As a lad I used string to communicate, and two tin cans ;)

@T W,

Can you recommend a specific device ?

If you just want to play and learn, TI has some ready-to-go eval modules for resonable prices:

www.digikey.com/.../998

Personally, my experience is with frequency hopping in the ISM band at both the baseband and proprietary protocol stack levels from the ground up using Motorola transceivers (the customer put out the development cost up front so in the end the system was theirs and they would recover from the ultra low cost of the board).

Thanks.

You do realise that "wireless" != "WiFi" - don't you?

WiFi is just one form of wireless connection; there are very many others - standard & proprietary; RF and other...

You need to clarify your requirements.

Since I am going to interface an iPad and want to avoid the costs involving using the proprietary Apple Bluetooth connection, I am going WiFi. Am I correct in assuming that every chip that supports (IEEE) 802.11 can "do something" to make other devices identify it as a network and allow them to connect to it, given a server waiting for a connection on the embedded side?

I think you are confusing hardware with software here. The way a hardware device interacts with its environment (ie: network) is up to the configuration of that device.

For example, what determines whether a Modbus device is the master or a slave? The configuration of that device by the software.

An 802.11 chip is much like an RS232 chip. It operates how it is configured to operate by the developer/user. Therefore, a device can be both master/slave or client/server if the software (and protocol) will support that.

A caveat is that I am sure that there are preconfigured chips out there that support either one configuration type or another. But why you would buy one like that I dont know, especially if you have the capability to do it yourself. HTH.

Yes, there are - this one for example:

www.lantronix.com/.../matchport.html

Tamir;

Take a look at the TI CC2540 series. They have a number of simple application examples to give you a good idea for your needs. This is a series of low power Bluetooth devices.

Remember that you will need an approved app to use a "standard" iPad.

Bradford

If you really want to use 802.11 this module may be of interest to you too, since you specifically stated a 'client device'. However, you are limited to data exchange with another device by the method(s) they support (simple ASCII command language) much like a SIM300 or Telit GSM module. Downside: there is really nothing to 'learn' about 802.11.

www.atim.com/.../rn-174-sdk-board-for-rn-171-wifi-802-11bg

In stock @ Mouser for a reasonable price:

www.mouser.com/.../

I have used two wifi modules so will try give you a summary of my experiences

Both use AT hayes type commands ( eg serial uart to module sending eg AT+STCP=xx.....)

Connect one nano socket approx £45 - no support only documents
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To connect to an external server socket - easy and quick

eg power up power up module,
set config, (device ip, power saving modes, timeouts, etc)
find AP, Find host(are you connected to a wifi network), find ssids , join ssid
find host device (eg ping) ip to find
open socket (ip and port to use)
send data ( socket handle, data length, data)
check if data recieved ( 10 bytes in wifi buffer)
read data from module (I/10:abcdef...)
close socket
power down if needed

found out by removing the command echo back it was a little easier to use module only responds with something like I/OK if command accepted I(0000) socket handle or say I(0005) reponse time to ping command

a little disconcerting is how long it can take to process commands eg joining networks with security e.g. 30s

Found in a car plant ( eg lots of metal and big moving things ) I could connect about 90 m away and send data to a linksys router acting as an AP

but in a office block with roughly 15 or so wifi networks the range was only about 10 m ( appartently wifi module throttle back on tx power)

you need some form of external power control simply because when it powers up it does a search for networks ( or something similar) and draws max curent about 200mA and if you have a flat lipo battery it drops the voltage enough to set of resets and it start again ( self buggering poopatron) can you guess how I know this ?

if it cant open a socket on a external eserver it comes back with something like
ERRROR (207)

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Gainspan wifi module (forgot model) (£25) - support from the uk office and a site in india but you can also pay support for about £500 if you need something a little more complicated

more or less similar but half the price - seems a little quicker to respond to commands
and still developing with this so learning but i like what ive seen.

a little differernt in how you send the data and recover it but still easy to use

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How they can be used

try connect to an external server - eg find a wifi network join it, then try open a socket on an external server

act as AP and open a server for client sockets to connect to( eg set the network ssid ) so you turn on ipad wifi search for wifis then attempts to form a socket with your system

web provisioning - (Gainspan )eg wifi module acts as an AP and when connected too provides a web page to the connecting device.

if you can connect to a phone module these are very similar

Are these they?

" href= "http://www.gainspan.com/products/GS1011M_modules.php">www.gainspan.com/.../GS1011M_modules.php

Yes on the connect one module

but this is the gainspan module www.gainspan.com/.../GS1500M_modules.php

Hi,

You can even check this WiFi module.
www.whiznets.com/wifi-modules.html

If you can share your MCU part no. I can then suggest you more.