
Disassembling the Amazon Dash - monkeypod
http://www.bitsofcents.com/post/118749233621/disassembling-the-dash
======
michaelt
One neat thing Amazon are doing with this product, which I hadn't considered
as an "internet of things" option, is making each unit of hardware order a
single supplier's goods. All the example buttons say "Tide" or "Bounty" or
"Gillette" or "Olay" right on the button - all Procter & Gamble. And the other
goods pictured [1] are all brand-name goods with fairly big marketing budgets.

In the jargon of the grocery industry, this means the buttons can be "supplier
funded" \- Procter & Gamble probably pay Amazon a reasonable portion of the
cost of the button, as a marketing method.

[1] [https://www.amazon.com/oc/dash-button](https://www.amazon.com/oc/dash-
button)

~~~
deegles
What if the Dash becomes very popular? I believe we'd see an explosion of
companies funding dash buttons which would, in my opinion, be a bad thing for
the customer. I don't like the idea of locking myself into a brand for the
life of the device.

I'd like to see a configurable button that orders, say, the cheapest paper
towels that have at least a 4-star rating. The suppliers probably wouldn't be
happy about the competition though.

~~~
DanBC
> I don't like the idea of locking myself into a brand for the life of the
> device.

You're not the target market. Some people exhibit strong brand loyalty for
some stuff. In the UK you'll get people saying that baked beans _must_ be
Heinz and no other brand.

I tend to agree with you. I want a button I can push to order the cheapest
washing detergent. But that gets complicated. Do I mean actual cheapest price
at the till, or do I mean cheapest per wash? Does that mean I want to buy a
huge 15 litre tub of industrial detergent?

> that have at least a 4-star rating.

Amazon ratings are already sub-optimal. I could imagine a time when all P&G
employees have to buy P&G products from Amazon, and have to give high star
ratings, in order to help fix the ratings. Perhaps I'm just overly cynical.

~~~
eridal
> Some _people exhibit strong brand loyalty_ for some stuff

..but the point is that these people can _choose_ to exhibit such loyalty.

This is well-studied and understood. People can stick with a brand for years,
until suddenly they change it for another and completely forgot about the
other.

The dash seems like just another convenient lockin

------
pelf
Is it just me that finds the entire concept of the Dash ridiculous?

I mean, what's the idea, having a button for every single product we buy? And
we need to set it up first. How is that any better than recurring ordering or
just opening the website and ordering it? Are we expected to have an entire
wall of dashes at our place?

I guess we'll need to sort them alphabetically or by color, so we don't waste
time searching for the button we need.

~~~
eli
Sure, but just a few decades ago there were people dismissing all of
e-commerce saying "why would I order online when I can just pick up the phone
and call in my order?" I'm sure before that there were people saying, Why do I
need phone ordering when I can just mail an order form to Sears? I think it's
a mistake to bet against a more convenient form of consumerism.

~~~
kbody
The problem with Dash is that it doesn't really scale.

~~~
minthd
This isn't the scaling phase. Dash is also an API for automated ordering. And
the button is a test to measure the usefulness of such API.Once there's data
proving the idea, and an available API, Amazon and it's partners will scale
this.

~~~
sangnoir
Good point about being an API. When combined with RFID, I can imagine smart
fridges / washing machines utilizing this API to automatically order (or
suggesting human do a 1-click order) when your Tide is about to run out.

------
rooiboss
So basically Amazon is tempting you to place wifi enabled microphones around
your house? I sure hope it's only capable of picking up high frequency audio.

~~~
yincrash
doing more listening/processing/data transfer than just the initial setup +
occasional button presses would make it drain its single AAA battery quite
fast.

------
spacefight
"Also on the bottom is the small microphone used for setting up the Dash."

Damn... another microphone in your household capable of recording sounds near
that device.

------
Sanddancer
All of those exposed pads on the pcb, as well as the silkscreening near a
quartet of pads labeled TX1 make me think this thing is going to be amazingly
hackable. The micro in there is no slouch by any means, and a wifi module is
always fun. I'm giving it at most a week before interesting things are done
with these.

~~~
joezydeco
Or one could just (pre)order the $19 Spark Photon and get a working module
with code, schematics, and support. Depends how you value your time.

~~~
meesterdude
i hate preorders! everything cool is preorder! Why can't the future be here
today?

is the spark photon really equiv to the dash? or does it still need other
components in addition?

~~~
joezydeco
FTA: _" At the heart of the Dash is a USI (Avnet) 850101. The 850101 is a
combination wireless module (Broadcom BCM43362) and micro controller (ST
Microelectronics STM32F205). This makes the Dash capable of connecting to
802.11 b/g/n networks with its 120MHz ARM Cortex-M3 processor. It also happens
to be exactly the same chip used inside the $19 Spark Photon."_

Avnet USI is just repackaging the chipset on behalf of ST and Broadcom.
Honestly, there are other things you can order today if you don't want to wait
for this one. You could try adafruit, sparkfun, or even digikey.

I personally recommend the modules from LS Research.

Module: [http://www.digikey.com/product-
detail/en/450-0064/450-0064-N...](http://www.digikey.com/product-
detail/en/450-0064/450-0064-ND/4006733)

Eval/Breakout board + Module: [http://www.digikey.com/product-
detail/en/450-0120/450-0120-N...](http://www.digikey.com/product-
detail/en/450-0120/450-0120-ND/4331950)

------
cubano
We wanted flying cars, but instead we got one-button branded soap ordering.

~~~
sukilot
Instasoap can't kill each other, tho.

------
aioprisan
Another always on microphone from Amazon in your home. Welcome to 1984!

~~~
mseebach
The microphone is only active when you hold down the button - if it's always
on (for whatever reason, accidentally or maliciously), the unit would run out
of power in a few hours, it's powered by a single AAA cell.

~~~
minthd
It doesn't have to be always on, it could be remotely controlled.

~~~
danellis
It's not powered up, though. That's why it lasts so long on one battery. The
button wakes it up.

~~~
userbinator
There's a 32kHz RTC oscillator in the MCU, which can be programmed to
periodically wake it up as well.

Without analysing the firmware you wouldn't be able to confirm for sure what
it's doing.

I suppose one exercise for those inclined would be to reprogram it to listen
(perhaps only during the daytime) and see how long it lasts. You wouldn't need
high fidelity so a low sample rate would be enough.

~~~
danellis
> Without analysing the firmware you wouldn't be able to confirm for sure what
> it's doing.

It's on your own network, so it's trivial to know when it's communicating and
with whom. In principle, it could periodically wake and poll a C&C server to
see whether it should start streaming audio or not.

~~~
ceequof
Nothing forces it to be on _your_ network. If there's a neighbor with open
wifi, or easily cracked wifi, or wifi Amazon already has the key for, (from an
Amazon tablet/phone that's been connected to it before) then it could talk on
that instead.

~~~
ars
You could measure power draw on the battery and make sure no power is ever
drawn except when the button is pressed.

------
ISL
I'm bummed that it's apparently vendor-locked. A configurable Dash would make
it applicable to all things Amazon. There are perhaps 100 places in our
facility that a '"consumable X needs a refill/attention". We don't need a
specific brand, and the brand we use can vary over time as needs and pricing
change.

~~~
rtkwe
> You will see a list of available options from the product line your Dash
> Button is associated with. For example, if your Dash Button can be used for
> Tide detergent, you may see a list of various Tide detergent scents and
> sizes that you can choose from. Tap the item to select it.[0]

That is disappointing, from the early materials it seemed like the face plate
was just branding and you could select anything you wanted. They're probably
partnering with the various brands that there are buttons for pay some of the
cost of manufacturing the devices. There might be a non brand locked version
coming in the future once they've moved past the initial release and rollout.
At least I hope so.

[0]
[http://www.amazon.com/gp/help/customer/display.html?nodeId=2...](http://www.amazon.com/gp/help/customer/display.html?nodeId=201746340)

------
PanMan
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?

~~~
joezydeco
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.

~~~
nemik
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.

~~~
joezydeco
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.

~~~
nemik
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.

~~~
joezydeco
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.

------
tomkinstinch
I'll put in a shameless mention that this is exactly the sort of content my
STEM education side project, TakeItApart[1] was meant to centralize. OP, we'd
love to see the Dash included on TakeItApart so others can learn from your
breakdown.

This annotation of the Dash components is terrific. It would be fun to probe
the exposed pads to see if they have left an STM32 SWIM/JTAG header available.
It's interesting that they choose to use a AAA battery but did not include a
battery door so that users could replace it. Perhaps that is coming? Still,
the power optimization is impressive considering how power hungry it can be to
do wi-fi RF transmission (on the order of a 1 watt).

1\. [https://www.takeitapart.com/get-started](https://www.takeitapart.com/get-
started)

------
discardorama
To steal someone else's tweet:

AOL in a big media deal, Clinton running for office, stocks at all time highs,
_new cuecat is here_. What's not to love about 2000?

------
flurdy
Dash was not an April fools?

~~~
IshKebab
No, and it was pretty clear it wasn't at the time tbh.

~~~
kubiiii
So clear that amazon did not bother avoiding around april 1st for the product
presentation.

------
danielsamuels
I imagine if you build up a collection of these for a variety of products
you'll need something to hold them all, perhaps it could be called a
DashBoard?

------
davb
Can anyone recommend any resources on power management on something like this?

My background in electronics is quite basic though I'd love to understand how
they managed to build an ARM-based, battery-powered device that is predicted
to last for years. I know it's not "always on" but it's fascinating
nonetheless and I think building something similar would make for a fun
project.

~~~
steckerbrett
Most microcontrollers have extremely low power sleep states, maintaining
interrupts on external inputs often only draws the smallest amounts of power.
When you're designing for low power electronics like this you often run into
the problem of the self discharge of the battery completely dwarfing any
consumption your microcontroller has. I'm reasonably confident they chose a
lithium AAA simply because they have very low self discharge, and a AAA over
something like a coin cell due to the rather enormous amount of power needed
to transmit 802.11.

I get the feeling that this device is pretty tentative for Amazon, they
haven't gone to huge lengths to keep the price of the build down. In
particular there's also a connector on the bottom right of the PCB that looks
a lot like it could be for a small screen or some other peripheral.

------
maguirre
Can anyone comment as to why they'd go for a cortex M3? @120Mhz it seems like
overkill for the function of this device. I know it's pretty cheap but it
could have made even cheaper with a less capable micro.

~~~
TickleSteve
The setup process involves some audio processing which requires slightly more
than trivial signal processing and also some RAM usage... Also handling the
network stack requires some RAM. The combination of those two requirements and
the low cost of the STM32s of that level of capability mean it was probably a
sensible choice.

~~~
zwieback
I'm surprised they went with F205, though. There are 32Lxxx chips with similar
capabilities and lower power.

The whole thing looks like a quick turn of a reference design and the real
low-cost design will follow later on.

~~~
TickleSteve
I would agree. It looks like a quick&safe design.... If it takes off, a cost-
optimised version will appear.

------
Ecco
Any clue about the software?

------
cognivore
Why is it I feel like this is just something that is designed to get me more
working hours?

I like going to the store, socializing, finding things to try, being a human.
Pushing a button doesn't do it for me.

------
alaskamiller
Why not a 2G cellular modem that sends out SMS? WiFi for location?

~~~
kondro
Cost of carrier access.

~~~
alaskamiller
Spark Devices negotiated with Telefonica for $3/1mb/mo global data plans.
Maybe the bigger question is... why can't there be cheaper data plans
available.

~~~
gambiting
$3 a month? That's really expensive for essentially a dumb button. Why would
you bother with a 3G modem if you can just use someone's Wi-Fi? Especially
since there's probably no GSM signal in your laundry cupboard,but a wifi
router will be nearby.

------
minthd
Why does amazon use a module,instead of certifying their own ? this hopes to
be a large volume project , so the savings could be considerate.

~~~
cushychicken
To me, the choice to use off the shelf hardware reflects Amazon's dedication
to lean values. In this sense, they're doing the absolute minimum (using off-
the-shelf hardware instead of spending 2 years spinning their own SoC) to
verify that their product (on-demand household commodity ordering) is actually
something people want. Makes a lot more sense in terms of turnaround time and
money - if the idea proves valuable, they can start expending the effort to
reduce costs through SoC development.

As the top commenter pointed out, though, I don't think they would really need
to spend the time recouping those margins - since all the brands signed up for
this service are big-name brands owned by Proctor and Gamble, it could
indicate a relationship wherein P&G helps them absorb some of the costs of the
hardware in exchange for what is effectively marketing.

~~~
joezydeco
What's also interesting is that the circuit board left on the micro-SMA
connector for an _external_ antenna.

The early press releases mention deeper hardware integration with consumer
products. I'm guessing they're going to be dropping this board into other
things besides the Dash product.

~~~
cushychicken
That's actually an RF testpoint, not an SMA connector (by which I think you
mean UF.L connector, like this guy:
[http://upload.wikimedia.org/wikipedia/commons/c/ca/U.FL_conn...](http://upload.wikimedia.org/wikipedia/commons/c/ca/U.FL_connector.jpg)).
It functions like a switch that is closed when the RF tester connects to it.

~~~
joezydeco
If you were to hook one of these up to the connector:

[https://www.sparkfun.com/products/11320](https://www.sparkfun.com/products/11320)

Would it not function as an external wifi antenna?

(and yeah you're right about the ufl. thanks for the correction)

~~~
cushychicken
In a sense, you're right - it's meant as a quick release testpoint for
conducted radio performance on a manufacturing line. Theoretically, you COULD
hook up an antenna to it, but you'd have to know some substantive details
about the integrated PCB antenna (impedance, center frequency, etc) to get
good or even comparable performance out of the external one. Probably not to a
male UFL connector, in any case - I'm 99% sure this type of connector is not
compatible with UFL.

Mileage may vary, of course, but in my experience this type of connector is
more frequently used to get conducted power RF measurements in manufacturing
settings.

------
ukandy
Irresponsible product design. Unnecessary and throwaway.

