Arduino - Send Email

In this tutorial we are going to learn how to use Arduino to send email.

There are serveral ways to send email from Arduino:

This tutorial uses IFTTT to send email. The code is available for Arduino Ethernet Shield 2 or PHPoC WiFi/Ethernet Shield.

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×Arduino Ethernet Shield 2
1×Ethernet Cable

OR

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×PHPoC WiFi/Ethernet Shield
1×(optional)Ethernet Cable
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Prerequisite

If you do not know about IFTTT and related concepts, We highly recommend you reading the following tutorials:

Wiring Diagram

  • Arduino - Ethernet Shield 2: we just need to stack the shield on Arduino Uno/Mega
  • Arduino - Ethernet Shield 2
  • Arduino - PHPoC Shield: we just need to stack the shield on Arduino Uno/Mega
  • Arduino - PHPoC Shield 2

How It Works

We need to create an IFTTT Applet on the IFTTT website, which connects Webhooks to Email service.

When we create the Applet:

  • We can compose the content of Email to be sent.
  • We can include data from Arduino to the Email content.

※ NOTE THAT:

The Email content is specified on the Applet, not in the Arduino code.

Workflow

  • Arduino makes an HTTP request to Webhooks of IFTTT,
  • Webhooks triggers Email service on IFTTT
  • Email service on IFTTT sends an email to the email address you used to create the IFTTT account.

How To Use IFTTT with Arduino

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

※ 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.

※ NOTE THAT:

Note that, you can create the IFTTT account by anyway. This tutorial creates the IFTTT account with the Google account. If you do not use Google account, the step-by-step instruction may be slightly different.

Arduino code

Arduino IFTTT code for Arduino Uno/Mega with Ethernet Shield 2

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-send-email */ #include <SPI.h> #include <Ethernet.h> // replace the MAC address below by the MAC address printed on a sticker on the Arduino Shield 2 byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; EthernetClient client; int HTTP_PORT = 80; String HTTP_METHOD = "GET"; char HOST_NAME[] = "maker.ifttt.com"; String PATH_NAME = "/trigger/EVENT-NAME/with/key/YOUR-KEY"; // change your EVENT-NAME and YOUR-KEY String queryString = "?value1=26&value2=70"; void setup() { Serial.begin(9600); // initialize the Ethernet shield using DHCP: if (Ethernet.begin(mac) == 0) { Serial.println("Failed to obtaining an IP address using DHCP"); while(true); } // connect to web server on port 80: if(client.connect(HOST_NAME, HTTP_PORT)) { // if connected: Serial.println("Connected to server"); // make a HTTP request: // send HTTP header client.println("GET " + PATH_NAME + queryString + " HTTP/1.1"); client.println("Host: " + String(HOST_NAME)); client.println("Connection: close"); client.println(); // end HTTP header while(client.connected()) { if(client.available()){ // read an incoming byte from the server and print it to serial monitor: char c = client.read(); Serial.print(c); } } // the server's disconnected, stop the client: client.stop(); Serial.println(); Serial.println("disconnected"); } else {// if not connected: Serial.println("connection failed"); } } void loop() { }

Arduino IFTTT code for Arduino Uno/Mega with PHPoC Shield

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-send-email */ #include <Phpoc.h> PhpocClient client; int HTTP_PORT = 80; String HTTP_METHOD = "GET"; char HOST_NAME[] = "maker.ifttt.com"; String PATH_NAME = "/trigger/EVENT-NAME/with/key/YOUR-KEY"; // change your EVENT-NAME and YOUR-KEY String queryString = "?value1=26&value2=70"; void setup() { Serial.begin(9600); // initialize PHPoC [WiFi] Shield: Phpoc.begin(); // connect to web server on port 80: if(client.connect(HOST_NAME, HTTP_PORT)) { // if connected: Serial.println("Connected to server"); // make a HTTP request: // send HTTP header client.println("GET " + PATH_NAME + queryString + " HTTP/1.1"); client.println("Host: " + String(HOST_NAME)); client.println("Connection: close"); client.println(); // end HTTP header while(client.connected()) { if(client.available()){ // read an incoming byte from the server and print it to serial monitor: char c = client.read(); Serial.print(c); } } // the server's disconnected, stop the client: client.stop(); Serial.println(); Serial.println("disconnected"); } else {// if not connected: Serial.println("connection failed"); } } void loop() { }

※ NOTE THAT:

This tutorial used the dynamic IP address (via DHCP). If you want to use the static IP address:

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  
  • You receives an email
  • Arduino Gmail receive

Video Tutorial

How to Include Sensor Data to Email Content

To include data from Arduino to Email content, we need to do:

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

Hi guy,


This is Arduino Uno, 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 email will be like below:

Arduino Email content

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:

  • Send an email notification when the button is pressed
  • Send an email notification when the door is open
  • Send an email notification when the temperature is too hot ...

The Best Arduino Starter Kit

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