Published November 2, 2025 © GPL3+

Automatic Medication Alert System Using ESP32 and Twilio API

A simple IoT-based drug reminder that sends an SMS alert at a preset time using ESP32, RTC, and Twilio API.

BeginnerWork in progress1 hour4

Automatic Medication Alert System Using ESP32 and Twilio API

Things used in this project

Hardware components

DFRobot DS3231M MEMS Precise RTC

Espressif ESP32S

Jumper wires (generic)

Software apps and online services

Arduino IDE

Twilio SMS Messaging API

Story

Elderly people missing essential medications such as antihypertensives can face serious consequences. To help reduce this risk, I built a simple automatic drug reminder using an ESP32, RTC, and the Twilio API. It sends an SMS to your phone at a set time, with messages like “Take Thyronorm on an empty stomach, ” ensuring both the medicine name and the instructions reach you on time.

This project is part of my ongoing “Smart Drug Box” series, where I’m exploring ways to make medication management easier and more reliable through simple, affordable electronics.

Acknowledgements:

I referred to Twilio’s API documentation and community examples while developing this project.

Setup:

1 / 2

Connect the RTC module to ESP32
Connect ESP32 to Wi-Fi.
Create a Twilio account and note your Account SID, Auth Token, and Twilio phone number.
Replace those credentials in the code and upload it using Arduino IDE.

Code

Automatic Medication Alert System Using ESP32 ,RTC and Twilio API

#include <WiFi.h>       # ESP32 WiFi library; needed to connect to the internet.
#include <HTTPClient.h> # for sending HTTP/HTTPS requests
#include <Wire.h>       # for I2C communication
#include "RTClib.h"     #  library for DS3231 RTC
#include <WiFiClientSecure.h> # handles secure HTTPS connections for Twilio.

const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

const char* accountSid = "YOUR_TWILIO_ACCOUNT_SID";
const char* authToken  = "YOUR_TWILIO_AUTH_TOKEN";
const char* fromNumber = "+TWILIO_NUMBER";   // include +
const char* toNumber   = "+YOUR_PHONE_NUMBER"";          // include +
const char* messageBody = "take thyronorm on empty stomach";

RTC_DS3231 rtc;   #creates an object for communication with RTC

bool sendSMS();

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
  Wire.begin();

  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

   rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); #adjusting time
WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
Serial.println("\nConnected!");

}

void loop() {
  
 DateTime now = rtc.now();
  int currentHour = now.hour();
  int currentMinute = now.minute();
  int currentSecond = now.second();


  Serial.printf("Time: %02d:%02d:%02d\n", currentHour, currentMinute, currentSecond);



  if (currentHour == 6 && currentMinute == 10 && currentSecond < 10) {
    bool ok = sendSMS();        
    if (ok) {
      Serial.println("sendSMS() reported success.");
    } else {
      Serial.println("sendSMS() reported failure.");
    }
    delay(60000); #wait a minute so it doesn't spam
  }

  delay(10000); # check every 10 seconds
}

bool sendSMS() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi not connected");
    return false;
  }

  # Use secure client for HTTPS
  WiFiClientSecure client;
  client.setInsecure(); 
  HTTPClient https;
  String url = "https://api.twilio.com/2010-04-01/Accounts/" + String(accountSid) + "/Messages.json";

  if (!https.begin(client, url)) {
    Serial.println("HTTP begin failed");
    return false;
  }

  # Basic auth with Account SID and Auth Token
  https.setAuthorization(accountSid, authToken);
  https.addHeader("Content-Type", "application/x-www-form-urlencoded");

  String body = "To=" + String(toNumber) + "&From=" + String(fromNumber) + "&Body=" + String(messageBody);

  int code = https.POST(body);

  if (code > 0) {
    String resp = https.getString();
    Serial.printf("HTTP %d\n%s\n", code, resp.c_str());
    https.end();
    return (code == 201 || code == 200);
  } else {
    Serial.printf("POST failed, error: %d\n", code);
    https.end();
    return false;
  }
}