This project is about the construction of a car alarm with remote control and Bluetooth that serves to arm and disarm the alarm with the control as well with the Android system phone through an application created with App Inventor and Arduino.
To do this project you only need a basic knowledge of App Invento and Arduino, as well as another little bit of car electronic.
I made this project as simple as possible so everyone can understand it, but if someone is interested, I also have a more complete version, with outputs for the horn and lights, as well as vibration sensor and open door detector and relay for cut the motor current, and also extra buttons in the application, to open the trunk and raise and lower the windows
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Step 1: Step 1: Parts
I bought all the parts on ebay at a good price from China, but if you do not want to wait 3 weeks for them, you can buy them from sellers in your own country, or locally
There are modules of this type that are fed with 3.3v, but the one that we need must be from 3.3 to 6v
Remote Control 315MHz/433MHz
We can use any model of remote that we want and in any frequency, either 315Mhz or 433Mhz, but the remote must match the frequency of the receiver
315/433 Mhz RF
Transmitter And Receiver Modules
This, regularly sold in pairs, with transmitter and receiver, but we only need the receiver, the only condition is that it works at the same frequency of the remote control that we choose
This Arduino was chosen for being the molest with a good number of pins
4 Channel Relay Board
This is responsible for converting the 5v signals of the Arduino into 12v outputs to control the car directly
Step-Down Adjustable Converter Power Module Regulator LM2596
This small will serve to convert the 12v power from the car to 5v to power the Arduino Nano and the Bluetooth module
Easy Install 10x 6
Pin HID Wire Connector Plug Male Female Harness Clips
It is not necessary to use this connector, but I liked it because in this way I can easily connect and disconnect the entire system
Plastic Project Enclosure Case
You can use the box that most convinces you, I prefer these to be able to hold them somewhere
Jumper Cable Kits
Indispensable to make connections easily
Step 2: Step 2: App Inventor
The required App Inventor knowledge is basic, only some buttons are occupied, the BluetoothClient and a few blocks
Download app: https://drive.google.com/file/d/1r-l_ICVFpYhDUeDxLrdgOkaz1kZu_PoL/view?usp=sharing
Step 3: Step 3: Arduino
I have simplified this project to the maximum so that it is easy to understand and only basic knowledge of Arduino is needed.
Library: : “RCSwitch.h”, I downloaded this library from the internet, and it is in charge of RF remote controls
You need to download this library, unzip it and copy it into the Arduino library folder that is usually inside the "my documents" folder
Download Library: https://drive.google.com/file/d/14Q17xwp9Rq2DUlwQL...
RCSwitch mySwitch = RCSwitch();
long int value = mySwitch.getReceivedValue();
if (value == 0)
if(value == 8481906)//BUTON TO DESARM
if(value == 8481905)//BUTON TO ARM
if(value == 9150562)//BUTON TO DESARM
if(value == 9150561)//BUTON TO ARM
char dato = Serial.read();
if(dato == 'A')//BUTON TO DESARM
if(dato == 'B')//BUTON TO ARM
if(dato == 'I')digitalWrite(Ignition,HIGH);//IGNITION
if(dato == 'S')digitalWrite(Star,HIGH);//STAR
if(dato == 'E')digitalWrite(Ignition,LOW);//CUT IGNICION
Download Code: https://drive.google.com/file/d/1cVSnlmAYO_WzOYA5H...
Step 4: Step 4: Diagram
The way to connect the device is a bit complicated, but not so much, you just need a car current tester, wire strippers and insulating tape.
Red Wire (Positive)
The supply current can be taken directly from the battery or any cable under the steering wheel with constant current, this is the current that is always there, even with the key in the OFF potition
Black Wire (Ground)
You can also take this from the negative of the battery or any wire or part of fixed iron under the steering wheel
In your car you need to remove the lid under the steering wheel and look for the wires coming out of the key switch, look for the ignition current, this is the current that comes out when you turn ON the key Switch
This is the starting current, it is a short pulse that comes out from the key switch when we turn and hold the key all the way
This wire is the one that sends the signal to unlock the car, you will find it on the left side or in the center of the car, right where the unlock button is
This wire is the one that sends the signal to lock the car and is also right where the lock button is
Once you found the wires just connect them all, it is only peel and splice
Step 5: Step 5: How Does It Work
Remote control RF 315Mhz or 433Mhz
The remote control has two buttons, one to arm and another to disarm the alarm
When the alarm is armed with the remote control, this one locks the car
When the alarm is disarmed with the control, this one unlocks the car
Android phone with App
The Android App has more features than the controls and it can be installed on all the phones you want
The first time you use this application you have to pair your cell phone with the Bluetooth receiver.
To do this you have to open your cell phone with Android system and open the phone settings, have the Bluetooth turned on and connect to your Bluetooth receiver, in case of asking for a password try with 1234 or 0000
Once you pair the receiver with your cell phone you can continue with the following