Internet of Things

Demonstrate communication between a microcontroller and another device. Optionally, work with a partner to control a device remotely.

For this project, I wanted to take advantage of some API technology. In passing, I had heard about API's from my friends who are into computer science and use arduinos to make all sorts of wacky things. A Youtuber I watch pretty frequently, Michael Reeves, once used an API to link up Twitter comments to another API to purchase Amazon products that users would request. In case you're curious, the video is here: https://youtu.be/hBP-NzOadL0?si=Wnd2ILzDVq-Qxr_R.

While not nearly as advanced, I wanted to use the powers of API for good and find a practical use for one of my projects. I forget my keys pretty often, so we wanted to make a device that would annoy me until I picked up my keys.

Yao and I first started off by finding the CallMeBot API, an API that could be used to send text messages over WhatsApp with some pretty simple code. The project is linked here: https://randomnerdtutorials.com/esp32-send-messages-whatsapp/

Setting up the API, I had to give them my IP address and some of my Whatsapp data. Little sketch, but what could go wrong? Unfortutnately for Yao, the bot ghosted her, but I was able to get the bot's digits and start texting.

We then used an ultrasonic sensor to detect whether or not my keys were present. The API will continually text me "did you remember your keys" until it senses that my keys have moved from the ultrasonic sensor.

I've walked away, but without my keys! The API will now continually text me until I notice and go get my keys.

After finally remembering to grab my keys, I take keys away from the ultrasonic sensor and the nightmares finally stop. No more texts from CallMeBot.

Here's the code that makes all of this run: 

 


  #include     
#include 
#include 


const int trigPin = 10;
const int echoPin = 9;

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;

const char* ssid = "AJKsamsung";
const char* password = "59925992";

// +international_country_code + phone number
// Portugal +351, example: +351912345678
String phoneNumber = "+16502766489";
String apiKey = "2897682";

void sendMessage(String message){

  // Data to send with HTTP POST
  String url = "https://api.callmebot.com/whatsapp.php?phone=" + phoneNumber + "&apikey=" + apiKey + "&text=" + urlEncode(message);    
  HTTPClient http;
  http.begin(url);

  // Specify content-type header
  http.addHeader("Content-Type", "application/x-www-form-urlencoded");
  
  // Send HTTP POST request
  int httpResponseCode = http.POST(url);
  if (httpResponseCode == 200){
    Serial.print("Message sent successfully");
  }
  else{
    Serial.println("Error sending the message");
    Serial.print("HTTP response code: ");
    Serial.println(httpResponseCode);
  }

  // Free resources
  http.end();
}

void setup() {
  Serial.begin(115200);

  WiFi.begin(ssid, password);
  Serial.println("Connecting");
  while(WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi network with IP Address: ");
  Serial.println(WiFi.localIP());

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
}

void loop() {
   // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  Serial.print("Distance (inch): ");
  Serial.println(distanceInch);

  
  delay(1000); 

if (distanceCm < 10) {

 // Send Message to WhatsAPP
  sendMessage("did you remember your keys");

}
 
}

}