SLN-ALEXA-IOT: Getting Started with Alexa Voice Service

This section describes the process of powering and connecting to the board as well as connecting the board to a Wi-Fi Access Point. There are multiple ways to provision the SLN-ALEXA-IOT kit onto a Wi-Fi network. These different mechanisms are listed in individual sections of the document.

These are the methods that can be used to provide the Wi-Fi credentials:

• Wi-Fi AP Provisioning – Using the mobile application;
• BLE Provision – Using the mobile application;
• Serial Provision – Using the terminal console;
• Wi-Fi client Provision – Using an established Wi-Fi connection.

The USB cable inside the box is split between power and data. The power part of the USB port has a single line connected and the data line has two lines connected.

Connect both USB-A connections of the provided USB splitter cable to your computers USB and the other end to the USB-C connector of your Alexa MCU Voice Kit.

When the board is connected to power, it should show one green LED (D1) which is the power indicator. The LED closest to the speaker (D2) is for indicating the state. This LED at startup should flash multiple colors to indicate it was powered. When the device is running the application code, it will blink yellow to indicate initialization.

Once the device has been initialized, the D2 LED will light orange to indicate that it is waiting for Wi-Fi credentials to be programmed into the device.

While this is not required, it should result in the Alexa MCU Voice Kit enumerating as a VCOM device. You can optionally open your favorite terminal with 115200, 8, 0, 1, 0 serial configuration and follow the remaining steps in this section

To make sure the setup is correct, one could type ‘help’ into the console. The output should be similar with the one shown in Figure 9.

While it’s not required, it is suggested that you type “enable_usb_log” to give you the best understanding on how the application works and possibly help debug.

To make sure the board is in the correct state, type “logs” which will give you the last few lines of the saved logs. At this point it should show logs indicating the device is waiting for Wi-Fi credentials.

When the device boots up from factory new state, it starts a Wi-Fi access point which will be displayed on any device that has Wi-Fi client available. The SSID will be “MCU_Voice_” with the devices serial number appended. The password of this Access Point is the serial number of the device.

Use the phone Wi-Fi network to connect to the device using these settings:

• SSID: MCU_Voice_<board_serial_number;>
• Password: <board_serial_number;>
• e.g. SSID: MCU_Voice_Rin4ZdJBFhM=,password: Rin4ZdJBFhM=.

Open the VoiceCompanionApp and select the “WIFI PROVISION” button to start the process of commissioning the Wi-Fi credentials on the device.

The Mobile Application will transmit multiple broadcasts and wait for one minute to receive the response from any number of SLN-ALEXA-IOT devices. Once the discovery process has finished, it will list the device as shown in Sending the Wi-Fi Credentials.

Please note, If the response data is not valid the application will display the following message: “Getting Invalid Data.”.

If the device is discovered, there will be a list of the available Wi-Fi networks. The “Refresh” button can be used to re-scan the Wi-Fi networks and to refresh the Wi-Fi list.

Select one of the available Wi-Fi networks from the list to provide the password associated with the Wi-Fi SSID. Once the password is correctly entered, press the “SEND” button to transmit the Wi-Fi credentials to the SLN-ALEXA-IOT kit or select “CANCEL” button to make another choice.

Once the credentials have been sent, the application will which informs the user to join with the mobile device the same wifi network that it’s used by the SLN-ALEXA-IOT device. Having both devices using the same wifi network is mandatory for the onboarding process.

Within the prompt, select the “GO TO SETTINGS” button which will open the Wi-Fi settings page. Connect to the Wi-Fi network which was sent to the SLN-ALEXA-IOT kit.

When returning to the application, it will verify that the Wi-Fi network that was joined on the mobile is the same as the one sent to the SLN-ALEXA-IOT kit.

If the Wi-Fi network is not the same as provided the application will ask to join the correct network. If the Wi-Fi network is the same as provided, the application will redirect to the “Discover” listing screen.

The VoiceCompanionApp can be also used to renew the Wi-Fi credentials only if the device is already connected to a Wi-Fi network.

Select the “Update” button on “Discover” menu to navigate to the Wi-Fi listing screen. To update the credentials, proceed with the workflow described in the previous section (2.1.3.1 Wi-Fi Provision – 0).

In this mode the credentials will be provided over serial terminal. The log should show that the device is waiting for Wi-Fi credentials over serial:

To connect to a Wi-Fi Access Point, type “setup <SSID> <Password>” and press enter. In the case of unusual characters, wrap the values in quotes (“”).

The device will begin to connect to the Wi-Fi Access Point with the LED (D2) changing to blue. Once the device is connected to the Wi-Fi access point, the LED (D2), will turn blue which indicates that it is waiting for discovery to start.

This section describes the process of onboarding the SLN-ALEXA-IOT kit to an Alexa account to access and use functionality in the Alexa ecosystem.

To be able to execute this section, the section “Booting and Connecting to Wi-Fi” must have been followed.

The device should be in a discovery mode state showing a blue LED (D2). Navigate to the VoiceCompanionApp on your Android phone and select the icon to open the application. When selected the splash screen in Figure 18 will show:

Once the VoiceCompanionApp has booted, it will display a screen describing the purpose of the VoiceCompanionApp when opening for the first time, after reading, press the next button.

After clicking next, the screen to start the onboarding process will be displayed. Before starting the process, make sure the mobile application is connected to the same Wi-Fi Access point as the SLN-ALEXA-IOT Kit to allow communication between the two devices. Press the Discover button which will send a broadcast message to find all available SLN-ALEXA-IOT Kits on the network

When discovery is complete, a list of all the available SLN-ALEXA-IOT kits will be shown with the serial number associated with it

If no SLN-ALEXA-IOT Kits are found on the same network, a “No Devices Found” message will appear in the VoiceCompanionApp.

If there is at least one SLN-ALEXA-IOT Kit shown, to validate which device you wish to onboard, retrieve the unique serial number by typing the “serial_number” command into the console and verify with the listed devices in the VoiceCompanionApp or by verifying the serial number displayed on the box.

To start the onboarding of the SLN-ALEXA-IOT Kit to your Amazon Alexa account, select the device you wish to onboard which will start the Login with Amazon (LWA) process.

NOTE: In the case that you already have the Amazon Shopping application, it will flash with LWA page and automatically associate with the account logged into the Amazon Shopping application.

Once the credentials have been entered and a successful login or registration has occurred, the VoiceCompanionApp will continue to communicate with the SLN-ALEXA-IOT Kit and display a completion percentage.

On the SLN-ALEXA-IOT Kit, the LED (D2) will change to a purple color which indicates the device is starting registration and it has received the information from the VoiceCompanionApp.

Note: the purple LED will only be on if the SLN-ALEXA-IOT Kit faces some problems during the LWA, otherwise, you won’t be able to see the purple LED.

When the Access Token from LWA has been received, the MCU Alexa Voice kit will begin to connect to the cloud and register with the AVS on MCU service, which will turn the LED (D2) orange while this is happening.

If the device fails to register, the Voice Companion App will display an error underneath the serial number in the list of “failed to register”.

Once the device has completed the LWA process, the Voice Companion application will update the percentage. The device will start blinking green every 500ms until the device has successfully connected to AWS IoT Core.

Once the device has successfully connected to AWS IoT Core, it will commence the registration and connection to AVS via AWS IoT which results in the device blinking green every 250ms.

Once the device has completed, the serial number in the Voice Companion App will change to yellow with the text being shown as “complete” while the SLN-ALEXA-IOT Kit turns the LED (D2) off and plays a chime.

The SLN-ALEXA-IOT Kit is now connected to your Amazon Alexa account. If you go into the Amazon Alexa application, the kit should be listed in your devices and called “NXP-Voice-Solution”.

The first indication that the device is listening is when the Alexa wake word is uttered. When the SLN-ALEXA-IOT kit detects the wake word, a cyan light will be shown as seen in Figure 32 and will start to listen and send microphone data to AVS via AWS IoT.

After the device has finished sending microphone captures to AVS via AWS IoT, the device will stop listening and go into thinking state. This state indicates that the AVS is processing the request and is trying to give the best response. While in this state, the devices LED (D2) will blink cyan and blue every 200ms.

After the device has finished thinking, it will start to respond. Before audio is outputted from the speaker, the LED (D2) will go into speaking state which is shown by blinking cyan and blue every 500ms.

While the LED (D2) is blinking as shown in Figure 33 the response from Alexa will start playing out of the speaker. The response should be indicating the weather conditions based on the location of your Alexa consumer account. Once this has completed, the LED (D2) will stop blinking and turn off to indicate it is now in an idle state waiting for the Alexa wake word as shown in Figure 31.

As indicated in the previous steps, the volume by default is set to the lowest level which is one. This is to ensure the speaker doesn’t disturb surrounding engineers in an office environment. To change this volume level, this can be done by asking Alexa.

This is done by uttering “Alexa” which will wake the device up, show the device in a state as shown in Figure 32 and start streaming microphone data to AVS via AWS IoT.

When the device stops listening and Alexa has received all of the request, the device will go into a thinking state which is shown in Figure 33. This means the device is waiting for Alexa to process the request and decide the best course of action.

Once the request is processed, Alexa will set the volume to ten which can result in the device responding with “OK” as well as showing the LED (D2) in Figure 33. The device will then change the volume, which is regarded as a device change, by blinking the LED (D2) white shown in Figure 34 below.

Upon the next interaction with Alexa, the response will be at the volume level set in above request.

Alexa supports multi-turn interaction which is a feature that allows continuous interaction with Alexa without having to utter the wake word every time.

To execute this feature, it is very similar to the simple question as previously shown. The first indication that the device is listening is when the Alexa wake word is uttered. When the MCU Alexa kit detects the wake word, a cyan light will be shown as seen in Figure 32 and will start to listen and send microphone data to AVS via AWS IoT.

Follow the “Alexa” utterance with the request “What’s the weather in Canada”, which when finished, will result in the device going into thinking state as shown in Figure 33.

When Alexa has identified the correct response, the device will go into speaking state as shown in Figure 33 and begin to output “What city in Canada” or something similar, out of the speaker.

Once the device has finished outputting the audio, it will move back into listening state, as Alexa is expecting a follow-on response. This will result in the devices LED (D2) to show the cyan color as shown in Figure 32. Utter “Toronto” to the device.

When Alexa detects the end of the utterance, the device will go back into thinking state as shown in Figure 33.

Once Alexa has detected Toronto was uttered, it will put the device into speaking state as shown in Figure 33 and begin outputting audio to the speaker with the Toronto weather update.

Alexa supports Amazon Music which is a feature that allows you to play music from your Alexa account including playlists.

To use this feature, it is very similar to the simple question as previously shown. When the MCU Alexa kit detects the wake word, a cyan light will be shown as seen in Figure 32 and will start to listen and send microphone data to AVS via AWS IoT.

Follow the “Alexa” utterance with the request “Play some music”, which when finished, will result in the device going into thinking state as shown in Figure 33.

When Alexa has identified the correct response, the device will go into speaking state as shown in Figure 33 and begin to output some Alexa response indicating it is going to play some music out of the speaker.

After indicating Alexa is going to play music, the device will go back into idle state as shown in Figure 31 and begin to play music out of the speaker.

While music is playing, barge-in can occur to interact with Alexa by following section 3.1.1.