ESP8266 -  Lab Five - Embedded Servers  - Solved

As the name implies, a server is a component or device that provides a service or function to a client device. Any web page you can access through the Internet browser and applications, like games and video services, are hosted on servers for users and clients to request and interact with.  All a basic server does is take in requests from a client and sends back a response.

 

In this lab, we will make our smartwatch application (more specifically the ESP8266) into a server that will take requests from a smartphone app through HTTP. More specifically, the smartphone app will send commands or requests to the smartwatch server, and the smartwatch will execute these commands.

 

Part One: Smartphone Application
Useful links: https://developer.android.com/develop/index.html 

http://www.instructables.com/id/How-To-Create-An-Android-App-With-Android-Studio/ https://developer.android.com/guide/topics/manifest/manifest-intro.html https://developer.android.com/reference/android/app/Activity.html https://developer.android.com/guide/topics/ui/declaring-layout.html https://developer.android.com/guide/topics/ui/controls/button.html 

http://android4beginners.com/2013/06/lesson-1-how-to-display-and-format-a-text-in-androidapps/ https://developer.android.com/training/basics/network-ops/connecting.html https://developer.android.com/reference/org/json/JSONObject.html https://www.tutorialspoint.com/android/android_json_parser.htm https://cloud.google.com/speech/ 

 

Create an Android smartphone application that will interface with the Google Speech API. The application should allow users to speak a voice command and send that command to the ESP8266 server via HTTP.

 

To download Android Studio, go to https://developer.android.com/studio/index.html and download the version appropriate for your operating system.

 

You can look on https://developer.android.com/develop/index.html to learn more about how to create an Android application; there are more links listed in the “useful links” section above. Once you have set up Android Studio, you can now create an application that interfaces with the Google Speech API. More information about the Google Speech API can be found here:

https://cloud.google.com/speech/.

 

 

 

General Tips for Running and Debugging Android applications: 

 

Developer Options: 

In order to download applications to your device from Android Studio, you must enable developer options and USB Debugging on your device. To do this, go to Settings->About Phone and tap Build number about 7 times until you get a message saying that developer options has been enabled. Once this is enabled, you should see a new menu item called Developer options appear in your Settings screen. Go into this menu and enable USB debugging.

 

Android Manifest
The AndroidManifest.xml file contains information that specifies how the application is setup (permissions the application requires, what activities are within the application, which activity is the main activity, etc.). For this lab, you must add the Internet permission and the speech recording permission because the application will record your voice and communicate to Google Speech API and the HUZZAH through the Internet. The image provided below details what needs to be added.

 

  

 

 

 

 

 

 

Activities and Source Code
Android applications run and allow users to interact with them through activities. You can specify what your application does through activities, specified in app->java. Essentially, the files in this folder contain the “source code” that specifies how your application functions.

 

  

 

Activity Layouts
The java source files specifies how your application functions, but any smartphone application also has a user interface that users can interact with. User interfaces can be created in .xml files located in res->layout. These screens must be linked to an activity specified in app->java.

 

  

 

Downloading the Application to your Device
Once you have enabled USB debugging on your phone and you have created your application, connect your phone to the computer. Click on the debug button, as shown below:

 

  

 

Once you click on the debug button, Android Studio will launch something called the “Android Debug Bridge” or ADB, which essentially allows you to transfer your application from Android Studio to your device. When the ADB launches, your phone will receive a notification, like the one shown below. You must accept in order for you to be able to load your application onto your phone.

 

  

 

Part Two: Smartwatch Embedded Server
Useful links: 

https://ngrok.com/ https://ngrok.com/docs  

1.    Once the smartwatch application is done, we must make sure the ESP8266 or smartwatch application can receive these requests. On the ESP8266 server, write a script that will allow the server to receive and process HTTP requests.

2.    Configure the smartwatch display to turn off and turn on, display the time, and display any other message on the OLED whenever it receives the corresponding command from the smartphone. In other words, interface the smartphone app with the smartwatch embedded server. In order to access a server via HTTP on the Internet, the server must have a global IP address, which the ESP8266 does not have by default; it only has a local IP. To get around this, use ngrok to create a tunnel connection to the ESP8266. The ngrok software is available here: https://ngrok.com/. More information on how to use ngrok can be found here: https://ngrok.com/docs.