ESP32 - Make Voice Phone Call

In this tutorial we are going to learn how to use ESP32 to make a real-time VoIP (Voice over Internet Protocol) call to your phone.

Hardware Required

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
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Prerequisite

If you do not have knowledge of IFTTT and related concepts, We highly recommend you reading the following tutorials:

How It Works

We need to:

  • Install IFTTT app on your phone (available for Android and iOS).
  • Create an IFTTT Applet on the IFTTT website, which connects Webhooks to VoIP Calls service.

When we create the Applet:

  • We can write the text message, which is converted to the voice message to be sent on the phone.
  • We can include data from ESP32 to the message.

Workflow

  • ESP32 makes an HTTP request to Webhooks of IFTTT,
  • Webhooks triggers VoIP Calls service on IFTTT
  • VoIP Calls service on IFTTT converts the text message to the voice message.
  • VoIP Calls service on IFTTT makes a call to IFTTT app on your phone.
  • Your phone is ringging.
  • You accept the call
  • The voice message is spoken.

※ NOTE THAT:

  • The message is specified on the Applet, not in the ESP32 code.
  • Since this is VoIP, your phone need to be connected to Internet.
  • VoIP call is free
  • ESP32 can speak to you, but you cannot speak to ESP32.

How To Use IFTTT with ESP32

  • Install IFTTT app on your phone
  • Create an IFTTT account and Login to IFTTT.
  • Create an Applet of Webhooks and VoIP Calls services. Please write down the event name we uses
  • After creating the applet, get Webhooks key from IFTTT.
  • Copy below ESP32 code and paste in Arduino IDE.
  • Replace event name and Webhooks key in the ESP32 code
  • Upload the code to ESP32

※ NOTE THAT:

  • The event name is given by you. You can give any name.
  • Webhooks key is created by IFTTT. You can not change it.

See the video tutorial at the end of this tutorial.

ESP32 code

Result

In the two above codes, If succeeded,

  • The result in Serial Monitor looks like below:
  • COM6
    Send
    Connected to server HTTP/1.1 200 OK Date: Thu, 14 May 2020 07:06:40 GMT Content-Type: text/html; charset=utf-8 Content-Length: 44 Connection: close X-Top-SecreTTT: VG9vIGVhc3k/IElmIHlvdSBjYW4gcmVhZCB0a== ETag: W/"2c-4f52ca3d" Server: web_server Congratulations! You've fired the test event disconnected
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  
  • Check your phone is ringging or not.
  • Accept the call
  • Hear the the voice message.

Video Tutorial

How to Include Sensor Data to Voice Message

To include data from ESP32 to the voice message, we need to do:

  • In ESP32: Include data into HTTP request (in the query string).
  • In Applet: modify the setting to extract data from the HTTP request.

You can learn what is query string in this tutorial

There are 5 variables we can use in the setting of the IFTTT Applet.

{{EventName}} Extracted from HTTP request
{{OccurredAt}} System time when event occurs
{{Value1}} Extracted from the variable value1 of query string in HTTP request
{{Value2}} Extracted from the variable value2 of query string in HTTP request
{{Value3}} Extracted from the variable value3 of query string in HTTP request

For example:

  • In ESP32: Change String queryString = "" to String queryString = "?value1=26&value2=70" in above codes.
  • In Applet: Modify the text message in the setting of the IFTTT Applet as follow:

Hi guy,


This is ESP32, I would like to inform you that:

- The outside temperature is {{Value1}} °C

- The outside humidity is {{Value2}} %


All the above value is measured at {{OccurredAt}}


Good luck and stay healthy!

In the above message, "
" make new line when displaying.

The voice message will be like below:

YOUTUBE VIDEO

You can read the temperature and humidity from sensor and put in the query string. See how to include data from sensor to query string

Challenge Yourself

Based on the above code, make the following project:

  • Make a VoIP call to your phone when the button is pressed
  • Make a VoIP call to your phone when the door is open
  • Make a VoIP call to your phone when the temperature is too hot ...

See Also

※ NOTE THAT:

Note that this tutorial is incomplete. We will post on our Facebook Page when the tutorial is complete. Like it to get updated.

※ NOTE THAT:

Note that this tutorial is incomplete. We will post on our Facebook Page when the tutorial is complete. Like it to get updated.

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