Amazon Echo Dot Teardown

2017-01-31 | By Maker.io Staff

There is no doubt that one of the most popular consumer products of 2016 was the Amazon Echo. Amazon Echo devices are designed to be a personal assistant. The voice known as “Alexa” is the command you give to the Echo device to activate the on-board list of commands.

I have been delighted in using my Echo dot and for some weeks now, it has been my new “Ask Google” device. Every time I want to google some information in their search engine, I now ask Alexa for the information. I have also been using Alexa as my morning alarm clock, to play my favourite music and to listen to my audible books. Whilst all these tasks are great and very useful around the home, I’m not sure I’m using the Echo Dot to its full potential.

In August 2016, SeeedStudio launched a Kickstarter campaign for the ReSpeaker. The ReSpeaker is an Open Source design voice assistant that you can program. Since reading about the ReSpeaker, I was intrigued to see the comparison between the Echo Dot. Curiosity got the better of me and I decided to hack open my Echo Dot.

The Teardown

Before we get started let’s take a look at what we know already about the Echo Dot:

• Dual band Wi-Fi 802.11 a/b/g/n
• Bluetooth 4.0 connectivity with A2DP and AVRCP audio profiles
• Built-in speaker and 3.5mm audio output
• 7 Microphone field array
• Micro USB powered
• Light ring
• Alexa voice search

The top of the Echo Dot features 4 buttons in total, two of them are for controlling the volume, one is used as an action button and the other is to mute the microphone effectively disabling Alexa. Disabling Alexa is also indicated by red LEDs on the light tubes and also the microphone button itself.

The top of the Echo Dot

The bottom of the Echo Dot features a firm rubber pad, which give the Echo Dot stability when placed on any surface. From my own experience of tearing things down, generally rubber pads are also used to hide screw holes and the Echo Dot is no exception to this. Stamped on to the rubber pad is also the compliance information such as FCC and CE markings.

The Bottom of the Echo Dot

Step 1

The first step involves getting the rubber pad off the bottom of the Echo Dot. The best way to do this is to use either a pick (see image below) or a flat head screw driver. Wedge the pick under the rubber pad and then work your way round the edges to loosen the rubber from the base, eventually you should be able to just tear it away from the base.

Remove the rubber pad with a pick

Once removed, there are four T8 star screws that will need to be unscrewed for the Echo Dot for it to come apart.

Unscrew the four T7 screws from the Echo Dot

Step 2

Tap the bottom white casing and you should be able to slowly lift off the white casing revealing top half of the Echo Dot.

Carefully remove the white enclosure

Before we remove anything else you should notice a small ribbon cable on the main circuit board. This ribbon cable is actually connected to the circuit board below the large metallic heatsink in which it sits on. To remove this ribbon cable you will need to carefully lift up the flap on the connector with a pick or flat screwdriver (Careful not to damage the PCB) and the pull on the tab to remove the ribbon cable from the connector.

Remove the ribbon cable

Step 3

You should now be able to disassemble the rest of the Echo Dot. First, remove the main PCB board which sits into the large heatsink.

Remove the main PCB from the heatsink

Now remove the heatsink and the rubberised pad that is used to reduce any vibration and also to protect the main PCB form getting damaged. Once removed then there is a white plastic mounting for the PCB underneath and then finally the second PCB. You will then be left with what would be the top of the Echo Dot with the plastic button and light diffuser around the edge of the Echo Dot.

Remove the remaining parts

If you noticed in the white enclosure there is also a black piece of plastic that sits inside. Inside there is the small speaker, you can remove this if you wish to take a closer look at the speaker but other than that the plastic housing is designed in a way that amplifies the audio from the tiny speaker, which you can see in the image below. The two small contacts on the

Echo Dot speaker

That just about sums up the teardown part, in the next section we will take a closer look at some of the components on the circuit boards.

Echo Dot Components

Main PCB Top

Main PCB Bottom

Power management IC

Wireless IC

MediaTek SoC

Digital to Analog Convertor

As you can see from the table above, Amazon have opted to use MEDIATEK as their main chip supplier with the power management IC, wireless IC and the main ARM CPU. MEDIATEK have a number of processor chips specifically for small devices including tablets and I believe the MT8163 is one of them.

Second PCB Top

Second PCB Bottom

Tactile Switch

Light Sensor

Red LED

The second PCB is where most of the interaction with the Echo Dot comes from. On the top of the PCB there are a total of four tactile dome switches. Each switch has a specific function from volume up and down, mute microphone and an action button. The mute microphone button has two red LEDs to indicate that the microphone is switched off and also has white PCB masking to reflect the LED light. The action button has a small light sensor next to it which after playing around a bit with the echo it detects the level of brightness and auto adjusts the brightness of the RGB LEDs. You will see this when you cover the action button with your finger for a few seconds.

On the reverse side of the second PCB is where all the microphone’s and RGB LEDs are placed around the outer edge of the PCB. You will also notice that the PCB around the edge has a white mask to help reflect the LEDs better around the light tubing. The microphones are connected to an analog to digital convertor, which converts your analog voice into digital signals to be sent to the cloud service. There are two microphones connecting to 1 ADC, therefore there are 4 ADC’s in total. All the RGB LEDs and the tactile buttons are connected to a microcontroller, which then connects to the main board using the ribbon cable.

ReSpeaker

ReSpeaker Core Module

Looking at both the Echo Dot and the ReSpeaker they are both no too dissimilar from one another. ReSpeaker uses two modules; the first features the processing IC’s such as Wi-Fi/Bluetooth and the main SoC, the second features the RGB LEDs and the mic field array for improved audio accuracy. Sounds familiar? Yes, the only major difference apart from the chipset is that the ReSpeaker uses a SD card slot as opposed to eMMC flash.

Like most SeeedStudio projects the ReSpeaker isn’t without the use of the Grove modular system, which allows you to interconnect a number of sensors and actuator to the ReSpeaker for voice control and automation.

Summary

If you interested in actually hacking into the MediaTek firmware/bootloader then I would highly recommend reading the article over at Medium. There is a small group of hackers who have already set out to re-program the Echo Dot but without any luck so far.

There is no doubt that the Echo Dot and Echo devices are going to be more popular throughout 2017 and I’m sure other manufacturers will also create their own variations of a personal assistant.

I’m super excited to see the ReSpeaker being released this year and I can’t wait to get a hold of one to start hacking my own projects. With the Echo Dot I’m currently limited to using the IFTTT channel for any hacks and DIY control over IoT devices.

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