Hi look at what we are going to do. A connected objet finder like a keyholder. We'll locate the object with a sound who's activated whith an android app i done. This app used Bluetooth.

Step 1: The Items Listing

We must do a few things and list item to use.

So we need: (links are present only to inform you. Buy where you want :))

Arduino Uno Card
Attiny45
Hc05 Bluetooth
Lithium batteries (Pay attention // I use batteries like this but maybe a button cell is cool too.)
Wires
soldering iron
battery recharge (if you need or want)

Step 2: What We Are Going to Do

The app called BeepIt speak with a bluetooth module who was connected on an arduino.

The arduino is too big and the code in it will be added in a AtTiny45 Microcontroller.

- 1 - We prepare the Arduino to speak with the attiny45 :

Read this link that works for me. http://highlowtech.org/?p=1695

After that :

Connect the Arduino Uno board to the USB port of your computer
Launch the Arduino program * Go (tools / serial port) select the COM port on which is connected to the Arduino board.

Go to (File / example) and click (ArduinoISP)

Go (Tools / Card Type) click (Arduino Uno)

Go to (File) click Upload

The Arduino is now able to program a ATtiny

Unplug the USB connector and make the small assembly.. (Picture Named : P1)

- 2 - Chose the Attiny45 in arduino IDE :

Reconnect the USB jack

Go (Tools / Card Type) click (Attiny and go another time to tools and chose processor 45 internal 8 MHz clock)

Go back into (Tools / programmer) click (Arduino as ISP) to indicate to the IDE that the UNO is used as a processor.

Go to (Tools) and click (Burn the boot sequence)

Go to (File) click Upload or icon * At the bottom of the window displays the following message Do not hold actually account if this message is that everything went well

- 3 - Program the Attiny45 in arduino IDE :

copy paste the code between ::::::::::::::::::::::::::

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

#include SoftwareSerial serieBT(0, 1); // on dit que l'on utilise les pins 10 et 11 à la place des pins 0 et 1 de la carte arduino

char val;

int buzzer = 2;// Borne de sortie buzzer connectée sur le attiny 85

void setup() {

//Serial.begin(9600);

serieBT.begin(9600);

pinMode(buzzer,OUTPUT); }

void loop() {

if (serieBT.available()) {

val = serieBT.read();

Serial.print(val); // on ecrit la valeur

switch (val) {

case '3' : digitalWrite(buzzer, HIGH);

delay(500);

digitalWrite(buzzer, LOW);

delay(500);

digitalWrite(buzzer, HIGH);

delay(500);

digitalWrite(buzzer, LOW);

delay(500);

digitalWrite(buzzer, HIGH);

delay(500);

digitalWrite(buzzer, LOW);

break;

} } }

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

- 4 - Now the code is in the Attiny45

We have to test our assembly (watch picture named : P2 )

In our code the Bluetooth RX TX are connected on the Attiny45 pin 0 et 1 and the buzzer on the pin 2.

Step 3: The Application

Next we must test the application and you have to upload it on your phone.

Download the app

Here the new link : https://drive.google.com/open?id=0B78-qX8DXDMsNUcz...

and the

Ai file https://drive.google.com/open?id=0B78-qX8DXDMsTlhs...

if you want change things on it (the file works on this plateform http://ai2.appinventor.mit.edu/

The application is free and you cant find it on Playstore for now so you have to download It.

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But as you already know it the code to hear the speaker is 3. So if you got and bluetooth sender/app and that you send 3 to the bluetooth module it'll respond.