In the summer prime sale at Amazon we purchased a third generation Amazon Echo Dot which is a small voice-controlled speaker using Amazon’s Alexa voice command service. Part Two of this post is on Echo Dot 3rd Gen Digging Deeper.
As this is the first Amazon echo dot device we have purchased, we decided to take it apart to see what you get for your £22.00.
In the Box
- The echo dot
- 240V UK power supply
- Things to try leaflet
- Setup instructions
- echo dot terms of use.
Top of the Echo
The top of the echo dot has four buttons, four microphones and an LED ring. The + and – buttons control the volume, the white circle activates Alexa and the circle with a line through it enables or disables the microphones.
Case Base
The base has the serial number, product logos and certification marks.
On the side is a power input socket and headphone / audio out 3.5mm stereo socket.
Case Base with sticky foot removed
The cover is held in place using adhesive tape and four plastic locator pins.
To open the case first you need to remove the non-slip cover on the base of the echo dot, using a thin knife or some other flat bladed tool.
Under the cover you will find four torx bolts and a recessed six pin header which appears to be a debug or programming port.
Removing the four torx bolts allows you to remove the plastic base.
Metal Chassis with Processor PCB and speaker
Inside you will find a circuit board and the internal speaker.
The underside of the PCB contains discrete components and several test points.
The base PCB is removed using three torx bolts and the removal of a small flat-flex cable. The four bolts that hold the power and headphone connectors down do not need to be removed.
Metal Chassis with Speaker
The Metal chassis contains the speaker and a plastic moulding for the speaker. The plastic is glued to the metal chassis, so we did not try to remove this.
There are four recessed torx bolts which hold the top panel to metal chassis.
Removing these allows you to remove the top PCB and button panel.
Processor PCB
The processor PCB houses the power input jack and a headphone / audio out port via a 3.5mm stereo headphone plug. There is a shielded section which houses the main processor and memory IC’s.
The board also contains power regulation and the audio driver for the internal speaker which is a TAS2770 from Texas Instruments.
Processor PCB with shielding removed
The metal shield can be removed using a small screwdriver. Under the shield you will find the Echo Dots main CPU and Flash memory.
The Echo Dot uses a Mediatek MT8516BAAA Quad-core, 64-bit ARM® Cortex-A35 MPCore processor.
Next to the processor is a Samsung KMFN60012M-B214 8GB eMMC memory chip.
Top PCB with White Plastic surround
The top PCB can be removed from the white plastic ring and top cover by removing the four silver torx bolts.
Top PCB with buttons
The top of the PCB contains four buttons, two LEDs and a light sensor.
The LEDs are placed on either side of the button which toggles the microphones on and off. The light sensor controls the brightness of the LED ring array.
Top PCB with Shielding removed
The underside of the top PCB contains most of the components found inside the Echo Dot. An array of 12 RGB leds is located around the edge of the board. The LEDs are driven using an ISSI IS31FL3236 36 channel LED driver.
Four microphones are placed next to the buttons and these feed into two TLV320ADC3101 chips from Texas Instruments. The TLV320ADC3101 is a Stereo ADC with an embedded mini digital signal processor. The Echo dot uses the four microphones to locate the direction the voice is coming from and filter out background noise.
In the centre of the PCB is a metal shield. Under the shield you will find a MediaTek MT7658CSN dual-band Wi-Fi and Bluetooth controller with an ARM Cortex-R4 CPU. The MT7658CSN manages communication to wi-fi and Bluetooth devices and connects to two PCB antennas located on the outer edges of the board.
There is also a Fairchild 74LCX74 dual D-Type flip-flop which appears to switch the microphones on and off.
Metal Chassis
The top of the metal chassis.
All internal parts
All of the internal parts which make up the echo dot.
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