Best (and cheapest) way to connect your project to Wifi?

[sarfata]

Hi!

I am wondering what solutions you have used to connect your projects to Wifi networks. I am designing a "smart" object and trying to reduce the cost as much as I can and right now it is the biggest line on the bill of material.

So far, I have found:
 * Roving Networks RN-131/RN-171 modules (the one I am using right now)
+ Can be hand soldered easily
+ Serial interface (or SPI)
+ Command mode (a little bit like AT commands)
+ Do all the TCP/IP stuff for you
- 27$ on mouser per 1000
- Cant do several connections at once

 * LS Research modules - for example:
http://www.mouser.com/ProductDetail/LS-Research/450-0037/?qs=sGAEpiMZZMsRr7brxAGoXTKY2y6hWySnVw1cy3ktLQk%3d
+ Wifi - Bluetooth - FM
+ SPI interface
~ 22$
- Not as well documented and reviewed that Roving network's
- I dont see any "onchip" DHCP - and the documentation I have found does not cover the software, it is mostly electronic only

* Electric Imp
http://electricimp.com/
+ Very small format (a SD card)
+ The SDCard wifi configuration is transferred to the card through an iPhone/Android application by "blinking"
+ Quite cheap (public price 25$ /unit) Prices in volumes not known yet
+ Some IO built-ins for real simple applications or Serial/SPI port (not sure which yet)
- Very new
- Communication HAS to go through a Electric Imp server. So no local network communication
I asked and received some of the early developers edition but have not had time to try them yet.

* USB Dongle based on Realtek chip (this is the solutions used by the BeagleBone or RaspberryPi)
Example: http://adafruit.com/products/814
+ Only 11$ finished product in a USB case - that is really really chip - I have not been able to find the chip on mouser/digikey. Does anyone know where to buy realtek chips?
- You have to provide the wifi implementation + tcp/ip (and maybe encryption?) which means seriously upgrading your host micro-controller (probably to something that can run Linux)

It seems to me that this is a very short list of options and that in those "Internet of Things" days, we should start to see much cheaper options and opensource design to do that (like 3Drobotics did with the 3DR radios: http://diydrones.com/profiles/blogs/announcing-the-3dr-radio-telemetry-system).

Any thoughts on that?

thomas
For more info on my project: www.tbideas.com

[westfw]

Note that that USB dongle solution also requires that your microcontroller support USB HOST functionality, which is pretty rare.

"Cheapest" seems to involve re-flashing some bargain-priced WiFi router; you can frequently get a whole router with power supply and etc for about the same price as as one of the bar WiFi modules.
http://hackaday.com/2012/06/12/nah-you-dont-need-an-ethernet-module-for-your-arduino/

I saw a WiFi enabled wall outlet (Belkin WeMo) at CostCo today.  A two-pack was about $40.
And I bought a "PogoPlug" for less than $25 a while ago.

So SOMEONE is able to build chip WiFi stuff...  Just not us. :-(

PS: waiting for a clever router vendor to include a PCB footprint for ATmega328 and some Arduino headers...

[firewalker]

There are some WiFi <-> RS232 modules over the Ebay.



http://www.ebay.com/itm/serial-ttl-rs232-to-802-11-b-g-n-converter-Embedded-WiFi-Module-with-antenna-B-/261080073995?pt=LH_DefaultDomain_0&hash=item3cc995c70b

Alexander.

[deephaven]

Microchip MRF24WB0MA/RM module at around $20 100 off price. But you would need to do the TCP/IP stuff on the micro. If you are intending to 'mass produce' your product this would be your best bet as you only need to sort out the networking stuff once and benefit from the lower cost of the module.

[sarfata]

deephaven: Thanks for the Microchip tip. At 1000's, the MRF24WB0MA is at $15.36 while the RN-171 is at 18.11. That's $3000 to spend on the TCP/IP stack. Looks like a very nice solution. I will look into it and there's already a bunch of tcp/ip stack available for avr chips.

firewalker: Thanks for the eBay suggestion - The modules on eBay are more expensive than the options listed above. I looked on alibaba.com and found a few modules available for a few dollars, like this one:
http://www.alibaba.com/product-gs/452324811/Wifi_Module_WK_W1.html
But all the very cheap ones I found were USB based.

westfw: I did not know about those Belkin products. They are brand new. It's very interesting. They are $49 on Amazon, I will try to stop by Costco and see if I can get them for $30.
I have googled around but it seems that no-one has opened them yet. They do say however than it looks like they have embedded a linux in there which would open the door to the very cheap USB modules. I will have to tear it down myself

Thanks a lot for the great inputs!

[T4P]

You can even find routers at less than $20 new ...

[cookie]

This is a very practical advice....I like

[jucole]

Sarfata - very nice project!  When I saw the UI I thought you could perhaps have like say 10 empty slots at the bottom then you could add favourite colours to fill them up, then it would slowly transition between them based on a user defined timer length or random etc. just an idea anyway! ;-)

[sarfata]

Jucole: Yes absolutely! More than just colors we want people to be able to create, edit and share color animations. The interface is still very much a work in progress Thanks for your interest!

[HackedFridgeMagnet]

Hi
The MRF24WB0MA only supports 802.11b which I think is getting a bit old now and doesn't utilise the bandwidth or power very efficiently.

I would use  802.11G or N.

Or possibly better for your uses is the zigbee protocol which is the same or very close to IEEE 802.15.4, which is more suited to low data rates, if that is what your project requires, I think it does up to 1Mbit/sec.
XBee Series 2 by digi is one example but is not particularly cheap or power efficient as a module, you might be able to do better.

[westfw]

I saw a WiFi enabled wall outlet (Belkin WeMo) at CostCo today.  A two-pack was about $40.

Either I mis-remembered, or they were initially mis-marked.  I was going to get some to take apart when I went shopping today, but they were $80 for two, which is more than I'll spend for something to break...

[Codemonkey]

Hi
The MRF24WB0MA only supports 802.11b which I think is getting a bit old now and doesn't utilise the bandwidth or power very efficiently.

I would use  802.11G or N.

Or possibly better for your uses is the zigbee protocol which is the same or very close to IEEE 802.15.4, which is more suited to low data rates, if that is what your project requires, I think it does up to 1Mbit/sec.
XBee Series 2 by digi is one example but is not particularly cheap or power efficient as a module, you might be able to do better.

ZigBee sits on top of 802.15.4, but at 2.4GHz, the bandwidth is 250Kbit/s, after protocol overhead its much lower.

[cookie]

I will try , thanks ,its  so  useful......

[HackedFridgeMagnet]

what about something from Nordic
http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24LU1P-OTP
I am not sure what is the most suitable chip. But below was cheap.

http://www.aliexpress.com/store/product/2-PCS-NRF24L01-Wireless-Transceiver-Module-2-4GHz-For-AVR-ARM-Arduino-MCU/209587_585320674.html

[sarfata]

Thanks @HackFridgeMagnet, this looks like the cheapest option if you have a powerful CPU. It does not seem to include any TCP/IP stack though, you have to be able to do that in software.

Also, something I did not put in my initial list is that some modules are already FCC certified as "sub-modules" and you can just put them in your design and avoid having to go through FCC certification again. This one does not seem to be certified.

thomas