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Set a timer - Wio Terminal

In this part of the lesson, you will call your serverless code to interpret speech and set a timer on your Wio Terminal based on the results.

Set a timer

The text returned from the speech-to-text call needs to be sent to your serverless code to be processed by LUIS, which will return the number of seconds for the timer. This number can then be used to set a timer.

Microcontrollers don't inherently support multithreading in Arduino, so there are no standard timer classes like those available in Python or other high-level languages. Instead, you can use timer libraries that measure elapsed time in the loop function and call functions when the timer expires.

Task - send the text to the serverless function

Open the smart-timer project in VS Code if it’s not already open.
Open the config.h header file and add the URL for your function app:
```
const char *TEXT_TO_TIMER_FUNCTION_URL = "<URL>";
```
Replace <URL> with the URL for your function app that you obtained in the last step of the previous lesson, pointing to the IP address of your local machine running the function app.
Create a new file in the src folder called language_understanding.h. This file will define a class to send the recognized speech to your function app, which will convert it into seconds using LUIS.

Add the following to the top of this file:

#pragma once

#include <Arduino.h>
#include <ArduinoJson.h>
#include <HTTPClient.h>
#include <WiFiClient.h>

#include "config.h"

This includes the necessary header files.

Define a class called LanguageUnderstanding and declare an instance of this class:

class LanguageUnderstanding
{
public:
private:
};

LanguageUnderstanding languageUnderstanding;

To call your function app, you need to declare a WiFi client. Add the following to the private section of the class:
```
WiFiClient _client;
```
In the public section, declare a method called GetTimerDuration to call the function app:
```
int GetTimerDuration(String text)
{
}
```
In the GetTimerDuration method, add the following code to build the JSON to be sent to the function app:
```
DynamicJsonDocument doc(1024);
doc["text"] = text;

String body;
serializeJson(doc, body);
```
This converts the text passed to the GetTimerDuration method into the following JSON:
```
{
    "text" : "<text>"
}
```
where <text> is the text passed to the function.
Below this, add the following code to make the function app call:
```
HTTPClient httpClient;
httpClient.begin(_client, TEXT_TO_TIMER_FUNCTION_URL);

int httpResponseCode = httpClient.POST(body);
```
This sends a POST request to the function app, passing the JSON body and retrieving the response code.

Add the following code below this:

int seconds = 0;
if (httpResponseCode == 200)
{
    String result = httpClient.getString();
    Serial.println(result);

    DynamicJsonDocument doc(1024);
    deserializeJson(doc, result.c_str());

    JsonObject obj = doc.as<JsonObject>();
    seconds = obj["seconds"].as<int>();
}
else
{
    Serial.print("Failed to understand text - error ");
    Serial.println(httpResponseCode);
}

This code checks the response code. If it is 200 (success), the number of seconds for the timer is retrieved from the response body. Otherwise, an error is sent to the serial monitor, and the number of seconds is set to 0.

Add the following code to the end of this method to close the HTTP connection and return the number of seconds:
```
httpClient.end();

return seconds;
```
In the main.cpp file, include this new header:
```
#include "speech_to_text.h"
```
At the end of the processAudio function, call the GetTimerDuration method to get the timer duration:
```
int total_seconds = languageUnderstanding.GetTimerDuration(text);
```
This converts the text from the SpeechToText class call into the number of seconds for the timer.

Task - set a timer

The number of seconds can now be used to set a timer.

Add the following library dependency to the platformio.ini file to include a library for setting a timer:
```
contrem/arduino-timer @ 2.3.0
```
Add an include directive for this library to the main.cpp file:
```
#include <arduino-timer.h>
```
Above the processAudio function, add the following code:
```
auto timer = timer_create_default();
```
This declares a timer called timer.
Below this, add the following code:
```
void say(String text)
{
    Serial.print("Saying ");
    Serial.println(text);
}
```
The say function will eventually convert text to speech, but for now, it will simply write the passed text to the serial monitor.
Below the say function, add the following code:
```
bool timerExpired(void *announcement)
{
    say((char *)announcement);
    return false;
}
```
This is a callback function that will be triggered when a timer expires. It receives a message to display when the timer ends. Timers can repeat, and this is controlled by the return value of the callback—this returns false to indicate the timer should not run again.
Add the following code to the end of the processAudio function:
```
if (total_seconds == 0)
{
    return;
}

int minutes = total_seconds / 60;
int seconds = total_seconds % 60;
```
This checks the total number of seconds, and if it is 0, exits the function without setting any timers. It then converts the total number of seconds into minutes and seconds.

Below this code, add the following to create a message to display when the timer starts:

String begin_message;
if (minutes > 0)
{
    begin_message += minutes;
    begin_message += " minute ";
}
if (seconds > 0)
{
    begin_message += seconds;
    begin_message += " second ";
}

begin_message += "timer started.";

Below this, add similar code to create a message to display when the timer expires:

String end_message("Times up on your ");
if (minutes > 0)
{
    end_message += minutes;
    end_message += " minute ";
}
if (seconds > 0)
{
    end_message += seconds;
    end_message += " second ";
}

end_message += "timer.";

After this, display the timer start message:
```
say(begin_message);
```
At the end of this function, start the timer:
```
timer.in(total_seconds * 1000, timerExpired, (void *)(end_message.c_str()));
```
This activates the timer. The timer is set using milliseconds, so the total number of seconds is multiplied by 1,000 to convert to milliseconds. The timerExpired function is passed as the callback, and the end_message is passed as an argument to the callback. Since the callback only accepts void * arguments, the string is converted accordingly.
Finally, the timer needs to "tick," which is done in the loop function. Add the following code at the end of the loop function:
```
timer.tick();
```

Build the code, upload it to your Wio Terminal, and test it through the serial monitor. Once you see Ready in the serial monitor, press the C button (the one on the left-hand side, closest to the power switch), and speak. Four seconds of audio will be captured, converted to text, sent to your function app, and a timer will be set. Ensure your function app is running locally.

You will see messages indicating when the timer starts and when it ends.

--- Available filters and text transformations: colorize, debug, default, direct, hexlify, log2file, nocontrol, printable, send_on_enter, time
--- More details at http://bit.ly/pio-monitor-filters
--- Miniterm on /dev/cu.usbmodem1101  9600,8,N,1 ---
--- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
Connecting to WiFi..
Connected!
Got access token.
Ready.
Starting recording...
Finished recording
Sending speech...
Speech sent!
{"RecognitionStatus":"Success","DisplayText":"Set a 2 minute and 27 second timer.","Offset":4700000,"Duration":35300000}
Set a 2 minute and 27 second timer.
{"seconds": 147}
2 minute 27 second timer started.
Times up on your 2 minute 27 second timer.

💁 You can find this code in the code-timer/wio-terminal folder.

😀 Your timer program was a success!

Disclaimer:
This document has been translated using the AI translation service Co-op Translator. While we aim for accuracy, please note that automated translations may include errors or inaccuracies. The original document in its native language should be regarded as the authoritative source. For critical information, professional human translation is advised. We are not responsible for any misunderstandings or misinterpretations resulting from the use of this translation.

9.6 KiB Raw Permalink Blame History Unescape Escape

Set a timer - Wio Terminal

Set a timer

Task - send the text to the serverless function

Task - set a timer

9.6 KiB

Raw Permalink Blame History Unescape Escape