Teardown: Amazon Dash Wand with Alexa
Some background: definitively introduced in mid-June 2017, the Dash Wand concept was first test-marketed back in April 2014. It's intended to hang close to or directly on, say, your refrigerator (thereby explaining the plastic "hook" with an adhesive-backed mount in the packaging; you'll see both it and the magnets inside the device shortly) and to be data-fed either by an integrated barcode scanner or by your voice, with audible feedback via a built-in speaker. It gives Alexa-powered responses to rudimentary questions you ask it, although to play music, for example, you'll need a fuller-featured Echo-family device.
At intro, for Amazon Prime subscribers such as my household, the Dash Wand was effectively free (well, ok, I ended up paying $0.90 in sales tax): buy it, activate it, and a $20 Amazon gift card shows up in your account in short order. You don't even need to use the Dash Wand to actually order anything before you get the kickback ... therefore this teardown. But as I said, you still needed to activate it. And given that I ordered it direct from Amazon, it (like many of its Amazon-branded peers) shipped pre-configured with my account and preferred Wi-Fi network credentials already stored; setting it up via the Amazon smartphone app was therefore incredibly easy (had I bought it from a third-party intermediary such as Best Buy, a few more steps would be involved):
Having dispensed with all steps necessary to qualify for my $20 refund, let the dissection commence! I'll begin with obligatory outer packing shots:
You'll note that, as with my earlier Dash Button teardown, I've (for privacy-preservation reasons) grey box-blocked out both the UPC and alphanumeric sequence associated with my unit's DSN (Dash Serial Number). This code, as its name implies, is device-specific and is also associated with my pre-configured Amazon account information.
Let's see what's inside:
Here's the aforementioned mounting hook, along with a pair of AAA batteries and a pair of literature snippets:
And here's the Dash Wand itself:
Next to the round button on one side of the device is a small oval hole for the microphone. On the other side is a larger opening for the speaker. And on one end is the protective plastic lens in front of the barcode lighting-and-scanning assembly:
The black half of the Dash Wand is rubberized, flexible, and easily pulled off in order to gain access to the battery compartment:
With it removed, you can also see additional FCC and other information stamped on the other side (once again, I've obscured both the QR code and alphanumeric sequence associated with my unit's DSN):
Time to dive inside. Unfortunately, there are no screws holding the two halves together; the unit (as with other equipment for which some degree of protection from moisture and other environmental factors, not to mention from consumers, is desirable) was ultrasonically welded. But persistence, elbow grease, and the combination of a narrow flat-head screwdriver and a box cutter got me inside (with no blood shed in the process, a bonus!):
Unfortunately, there was one casualty (in addition to the permanently damaged case); the flex PCB interconnecting the barcode reader assembly and the system board was stabbed by the screwdriver during the prying-apart process, ripping it from the connector, which ended up worse for wear:
The earlier mentioned protective plastic lens is glued around its entire periphery, and ended up on one side of the separated case with the barcode reader assembly normally behind the lens on the other:
Here's a close-up of the important portions of the half of the device with the assembly:
On the left is the magnet cluster that enables the Dash Wand to cling to a refrigerator or other metallic surface. On the right is the barcode reader assembly. And underneath it (trust me, you'll soon see it) is the mono speaker, connected to the system board via twisted-pair wiring.
Here's another closeup of the system board on the other half of the device, still in the case:
Remove three screws and the PCB lifts right off. You can see the underside of the switch, along with the rubber "o-ring" surrounding the opening for the microphone in the case. Shortly, you'll see what they both mate with.
As for the system board itself ...
In the upper right corner is a Wolfson Microelectronics (now Cirrus Logic) WM8904 audio IC for driving the speaker and handling the microphone input. The microphone itself is on the far right, next to the QR code sticker; you'll shortly see how the incoming audio gets to it. At the lower right corner, below the WM8904, is the speaker's twisted-pair connector. In the middle is the main system processor, an Atmel (now owned by Microchip) ATSAMG55J19A-MU (PDF) ARM Cortex-M4-based microcontroller. In the upper left corner is Texas Instruments' TPS61091 3.3V-output boost converter. And in the lower left corner is a Micron M25Q128A serial-interface NOR flash memory. Here's a closeup:
Flip the system board over and ...
In the center of the board is the switch controlled by the device's button, surrounded by four LEDs (D60-D63) to selectively illuminate the ring around it. On the right edge is an embedded trace-etched antenna; additional embedded antenna structures are above and below it (Readers: correct?). See the PCB hole just to the left of the main antenna? It matches up with the microphone hole in the case, and on the other side of it is the previously mentioned microphone. And to the left of it are (above) an Microchip ATWINC1500B Wi-Fi controller module and (below) a Cypress CYBL10563-68FNXI Bluetooth Low Energy chip, used for initial setup. Below are closeups of various portions of this side of the system board:
Thanks to both Matthew Petroff and the folks at WikiDevi for their assistance in ID'ing some of the ICs, by the way!
Remember the magnets I mentioned before? Remove two screws, pry away the retaining bracket and they come into clear view: