Cheapest way to add wifi to a project [duplicate]

I need low power wifi for a not-very-data-intensive application. What modules or chipsets should I look at? Other than low cost and low power, I have no restrictions. The cheaper the better.

This is for a high volume product, so both hobby level (since I can trace it back to an oem module) and oem level suggestions are welcome.

• Do you need 802.11a/b/g/n? – pingswept Apr 22 '10 at 15:54
• Do you plan to implement the TCP/IP stack on your own uC or do you want the module/chipset to provide that too? – mtrw Apr 22 '10 at 19:29
• @pingswept - g and n would be nice, but b is fine. @mtrw - I can go either way. – Adam Davis Apr 23 '10 at 23:41
• @adam can you tell us who did you use at the end? – Frank Aug 31 '11 at 8:36

There is a list of suggested wi-if modules in this very closely related question:
ideal-wifi-to-serial-or-spi-bridge

• I am downvoting this because link-only answers are strongly discouraged: At least try and summarize what the link provides as information, or, in this case, just nominate the question for closing, on the basis that it is a duplicate, if you so feel. – Anindo Ghosh Apr 24 '13 at 7:48
• I would have voted to close this question, but I do not have enough reputation to do that. So I did what I thought was the next best thing, but now I have even less reputation because of the down votes. – mjh2007 Apr 24 '13 at 12:37
• You did have enough reputation to comment, and that's what you should've done. You could also flag this question for moderator attention. Your edit doesn't change anything, this is still a link-only answer without any useful direct information. – user17592 Apr 24 '13 at 12:49

A very cheap way to add WiFi to a project, is to use a WiFi router as WiFi hardware. The router needs to be not-so-new in order to be cheap, and must support

• Serial/USB or JTAG ports on board
• OpenWRT (DD-WRT may work too, but I haven't used DD-WRT for this purpose)

See OpenWRT supported hardware page for information on what hardware is supported (note that DD-WRT supports more hardware). Router firmware already has a web server (for serving and admin page), a linux kernel (usually Busybox), and most everything else you need to have a functional WiFi interface. Since OpenWRT is.. you know.. open, you can do whatever you want on the router side of the equation.

Many routers have USB connectors built in. Others have pads on the PCB that can be soldered to. This provides the router/microcontroller interface.

One solution is to get the router to do most of the interfacing for you (i.e. run a web server / web client, which the router/openWRT does already), and have your microcontroller just respond to get data requests or push data to the router via the serial/JTAG connection.

As an example the D-Link DIR-601 can be found bought for about $5, has a serial port pads (some soldering required) and supports OpenWRT, albeit the flash space is a bit tight. Low power and small form factor this device surely isn't, but you cannot beat the price. I haven't used this chip myself, but I've looked at the Epcos B30810 series before. They're about$6 in low quantity, and below \$2.50 in large quantities. Digikey has them in stock. Unfortunately, their datasheets are behind a signup form.

I'd also look at the Atheros chips. I think the most recent low-power one is the AR6003. I don't know how much it costs; I suspect you'd have to buy it from Atheros directly. I'd be a little wary of the 0.4 mm spacing on the BGA pads-- below 0.5 mm generally costs extra.

• The datasheet for the Epcos B30810 is freely available from Digikey, and it doesn't look like to me that it actually implements an IP stack, so this doesn't look like a complete solution to me – angelatlarge Apr 24 '13 at 8:26

Check the WIZnet WIZ610wi modules. It is not clear from the website but AFAIK they have a normal TCP/IP stack hardwired in addition to the WiFi<->Serial bridge.

EDIT: Unfortunately it seems it does not have a TCP/IP stack for client use. You need to connect to the MII interface with their W5300 (which handles TCP/IP with 8 sockets) or some other MAC to get TCP/IP.

The problem you are going to run into is that the big boys like Marvell and Broadcom will not talk you unless you are someone like Apple. What I have has luck with is someone like Wi2Wi who acts as the bridge to vendors like Marvell.

Features

• 41mm x 31mm
• Microchip MRF24WB0MA WiFi module:
• 2.4 GHz 802.11b/g/n transceiver with built-in PCB antenna, range up to 400m (1300ft)
• FCC certified and WFA certified
• 1 Mbps operation
• infrastructure and ad-hoc network modes
• ATmega328P microcontroller with 16 MHz 0.005% quartz crystal. The microcontroller includes:
• 32Kbytes FLASH (512 bytes used for bootloader)
• 2Kbytes SRAM
• 1Kbyte EEPROM
• 6 10-bit analog inputs, 3 timers, serial, I2C, and other peripherals

If you only need a few metres range, the Nordic nRF24L01+ chips are cheap and quite easy to use.

• Sadly, not wifi. They are nice chips though. – Adam Davis Apr 23 '10 at 23:46
• The RFM70 (note: I am biased, I sell them) seems to be a cheaper lookalike-but-not-totally-compatible variation on the NRF24. – Wouter van Ooijen Aug 31 '11 at 17:49

Wifi is a pain in the butt, with the TCP/IP stack and all that. You should consider Bluetooth instead. They have RS232->Bluetooth modules...BlueSnap is their name, I think.