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by PanMan 4052 days ago
I'm disappointed that it isn't powered by the kinetic energy of the pressing: I heard some Philips Zigbee control devices work that way (but Wifi might be too power hungry for that). And I was expecting them to use the ESP8266 for this: Does anybody know if (at scale) that would have been cheaper?
4 comments

It doesn't look like the ESP8266 has the necessary I/O to do the audio provisioning trick that the Dash is doing with that hybrid module.

Provisioning these things can be a hassle sometimes. The TI CC3xxx has a really wacky one. A custom provisioning app transmits the SSID and password of the target network by sending encrypted packets to nobody: the CC3xxx sniffs the length of the encypted packets and picks up the necessary information from the string of those length bytes.

The audio thing is a lot more elegant, but needs some filtering and processing to make it happen.

The CC3XXX "SmartConfig" was complete garbage the last time I was evaluating it on a CC3200. It didn't work on 802.11n networks, only b/g. And that was when it worked. I got it only once trying on both an iPhone and Nexus 5, I would hate to have to answer any customers' support questions about using something so flaky.

The audio thing does require an app though to do provisioning, which I suppose isn't a problem for the kinds of people ordering this thing.

My preferred provisioning method is to let the little Dash-like device broadcast some setup or config access point. You connect to it, get an HTML UI to input target AP credentials into, and submit the form. It works from just about any device.

Totally agree about the SmartConfig. Interesting idea, very convoluted method.

Thankfully most devices I've been working on have a touchscreen to provision the SSID/PW, or we just ask the user to put it in a text file and inject it via a thumb drive. It really doesn't have to be this hard.

Agreed, but touchscreens and SD or USB means connectors, which are often a significant part of BOM cost and take up space. If you can do it all from the one-chip/module you have in there it's a big benefit when it comes to making something small and cheap.
Like I said, I've been fortunate to have alternate provisioning means.

I think the audio trick is a pretty elegant hack. Device agnostic and doesn't need a lot of handholding. But it also has an impact on the BOM. You need to add that Cortex M3 + microphone to sniff it out. Otherwise the whole thing could have been run off one chip like the ESP or GainSpan GS2100.

Doing the access point-to-client switcharoo is a good one too but needs a bit more instruction on the customer side, plus a way to whack the device back into setup mode when you need it.

The ESP8266 has peak draws of almost a watt when transmitting, unless Amazon releases a crank-to-order device that doesn't seem particularly plausible. I'm slightly surprised that they didn't use the Espresso solution here to keep their part count down, but it is possible this model is just to gauge market interest.
I'm not sure if the 8266 could be powered kinetically - wifi is particularly power hungry.
You are disappointed a wifi device isn't powered by the force of pressing a single button? High standards...