Evaluating wifi modules for DIY devices.

I’ve been research various wifi modules for use in future DIY devices and wanted to document and share my thoughts. I’m looking for something that’s cheap, easy to communicate with (which, for me, means an Arduino library), and easy to embed in a custom circuit board design (i.e. possible to solder by hand and not requiring specific / complex traces for the antenna). Here are some of the modules I’ve been looking at.

TI CC3000

Photo by SparkFun.

Photo by SparkFun.

This seems to be a popular option. There’s a breakout board from both Adafruit and SparkFun, along with Arduino shields and Arduino libraries from each. The module itself is small, although not that cheap ($23 on SparkFun was the best price I found). It’s probably not possible to solder with a manual iron, although it might not be too bad to do with a hot-plate.

I have done some initial experiments with these modules (using the Adafruit shield, breakout board, and Arduino library) and it’s been working reasonably well. You can see my circuit and code on GitHub. Getting Temboo working required some tweaks to their automatically-generated code. See my Weather sketch for a version that seems to work.

ESP8266

Photo by Adafruit.

Photo by Adafruit.

This is a fascinating possibility. It’s small, cheap ($9 on Adafruit), and easy to solder (a 2×4 0.1″ header). I’m not sure how well it works, but it seems that there are various attempts at Arduino software libraries out there. I just ordered a few, let’s see how it goes. (SeeedStudio also carries this and has some documentation, albeit mostly in Chinese.)

Roving Networks WiFly Modules

Photo by SparkFun.

Photo by SparkFun.

These have been around for a while and don’t seem to have caught on too widely, although SparkFun carries various versions. The RN-171 looks easier to solder but requires an external antenna (and corresponding PCB traces). The RN-131 has the antenna built-in, but all the pads are underneath the board (and, at $50, it’s expensive). SparkFun has a library for the module, but I haven’t tried it.

ACKme Wi-Fi Modules

According to a note on this Adafruit product list, ACKme is from the team that built the Roving Networks modules (now owned by Microchip) — and it shows. These seem very similar to the WiFly modules, except that they’re cheaper ($15 or $25 dollars instead of $30 or $50). They’re also newer, so they don’t seem to be as widely available yet (although you can find them on Mouser). It’s also not clear to what extent the Arduino library works. (There’s documentation and code for it, but the main ACKme product pages say that the library’s not finished.) Again, though, these modules have a similar trade-off as the Roving Networks ones: the module with antenna is more expensive, and the one without is harder to incorporate into a custom design.

 

I’ll be trying out some of these options over the next few weeks and try to post updates here as I find out more. There are, of course, lots of other options for embedded wireless connectivity (e.g. Spark, Raspberry Pi w/ USB wifi dongle, etc.) but I’ve been looking specifically for wi-fi, plus Arduino compatibility and the ability to embed into custom PCBs. For a more wide-ranging round-up, see this list from Postscapes.

Do you have any experience with these or other modules? I’d love to get your advice! Please post in the comments below.

Wednesday, January 21, 2015

 

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