Key Finder Device

Hi every one this project is a Key finders, also known as key locators, or electronic finders, are small electronic devices used to locate misplaced or stolen objects, such as keys, luggage, pets, or tools, and to transmit alerts.

e.g., that one's restaurant table is ready or a nurse is needed. Some key finders beep or flash lights on demand.

Components required

1. Hc-05

2. Attiny 45/85 IC

3. Buzzer

4. Switch

5. Battery & charger (I used 3.7v liPo battery with charger).

6. 8 pin IC stand (optional for reprograming or reusing the At tiny ic).

7. small Doted bord.

8. some wires & lead to soldering.

I have used ATtiny 45 , you can use any as per availability.

The final device should want to be small , like a key chain size. so 8 pin AVR ATtiny ic is suitable for this project. The memory of the IC is small so i made the program code in short. memory of 85 > 45 IC. You can perfectly make this device with the code i already done.

The above img shows the pin diagram of the Attiny 45/ 85 IC it contain Analog and Digital pins.

i used arduino uno to upload the code in attiny 45 /85 IC.

https://drive.google.com/file/d/1wDvfLF3cqBCQ6Q4bi...

CODE OF THE KEY FINDER.

You can do it with the Arduino uno or nano

There are so many video in youtube like “how to program attiny 45 using arduino uno”

Click here for one -> https://youtu.be/i9WOwDrpRKs

the above image is from the video link , he is explaining very well, watch it and upload the code in IC.

#include<SoftwareSerial.h>
#define RxD 0
#define TxD 2


SoftwareSerial blueToothSerial(RxD,TxD);

int led = 3;
int dis =1;
int condact=1;


void setup() {
  
 pinMode(dis, INPUT);
  
   pinMode(RxD, INPUT);
   pinMode(TxD, OUTPUT);
   setupBlueToothConnection();
    pinMode(led,OUTPUT);
  digitalWrite(led,LOW);
}

void loop() {
  
condact=digitalRead(dis); 
  if (condact== LOW)
{
  digitalWrite(led,HIGH);
} 
else
{
      digitalWrite(led,LOW); 
      char recvChar;
      //check if there's any data sent from the remote bluetooth shield
    if(blueToothSerial.available()){
      recvChar = blueToothSerial.read();
      
        if(recvChar == '1')
        {
          digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW); 
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW);
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW); 
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW);
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW); 
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW);
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW); 
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW);
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         digitalWrite(led,LOW); 
         delay(100);
         digitalWrite(led,HIGH);  
       delay(100);
         
        }

        else
       
          digitalWrite(led,LOW); 
       
  }
  }
}
void setupBlueToothConnection()
{
  blueToothSerial.begin(9600); 
  blueToothSerial.print("\r\n+STWMOD=0\r\n"); 
  blueToothSerial.print("\r\n+STNA=HC-05\r\n"); 
  blueToothSerial.print("\r\n+STOAUT=1\r\n"); 
  blueToothSerial.print("\r\n+STAUTO=0\r\n");
  delay(2000); // This delay is required.
  //blueToothSerial.print("\r\n+INQ=1\r\n"); 
  blueToothSerial.print("bluetooth connected!\n");
  
  delay(2000); // This delay is required.
  blueToothSerial.flush();
}

Just connect same as i shown in above image.

https://drive.google.com/file/d/1ZM0T62TkP4bBMuBU_...

Circuit image LINK.

you can remove or add the charger module as u like.

The 3.3v cell battery will not provide enougf ampre to the HC-05 and IC so no use with 3.3v button cell battery.

Dont buy and waste button cell battery.

I Have made a app in mit app inventor.

https://drive.google.com/file/d/1s_jbsEL47hXlUxcWb...

app download link.

One more main thing ,the app will auto connect my hc05 only.

If you want to autoconnect your device ,you (or I want to enter the address of your hc 05 in that app ). I can do it for you if you want ,***just send me the hc05 address****.

I tried to develop the app to auto save and auto connect all device but I failed.

Just send your HC05 address i will make the app which auto connects your HC05.

so thats all the work.

Feel free to ask any help, anytime time i will replay if i am online.

My whatsapp no: - 7012674684

follow my works and support in youtube for more projects

IF you want to view the video of this project , or how to connect.

go through the link