Description: A 3-axis accelerometer sits at the heart of this project to provide a nifty little motion detector. Want to know who is stealing from the cookie jar? Want a simple home intrusion detector? Or to test your partner's driving skills? Then have a look at this:
Overlay the Seeed Studio Base Shield onto the Freetronics Eleven (or compatible Arduino).
Use a Universal Cable to attach a Seeed Studio Grove Button to Analog Pin 0 on the Base Shield. The socket is located directly above the Freetronics Eleven Power plug, and next to the Reset button on the Base Shield. Please note that Analog Pin 1 is not used by the Grove Button.
Use a universal Cable to attache a Seeed Studio Grove Buzzer to Analog Pin 1 on the Base Shield. This is the socket next to the one used in Step 2.
Solder the female header pins to the Protoboard. Overlay the protoboard onto the Base Shield to create a third layer. I created this layer to tidy up the project and make it a little bit more portable. You could just wire up another breadboard on the side.
Stick a mini-breadboard (4.5cm x 3.5cm) onto the protoboard. This allows you to use the protoboard for other projects.
Solder the male headers to the 3-axis accelerometer, and then place it centrally onto the breadboard.
You need 5 wires to connect:
GND on protoboard to GND on accelerometer
5V on protoboard to VIN on accelerometer
Analog Pin 3 on protoboard to X on accelerometer
Analog Pin 4 on protoboard to Y on accelerometer
Analog Pin 5 on protoboard to Z on accelerometer
Connect digital pin 8 to an LED and 330 ohm resistor on the breadboard,
Use a wire to connect the resistor mentioned above to GND on the protoboard
Connect the USB cable from your computer to the Freetronics Eleven, and upload the Arduino Sketch to the board.
Disconnect the USB cable, and then power the Freetronics Eleven using a 9V battery and clip.
When you press the button, it will sound 3 warning sounds before it becomes activated.
If it detects a vibration or motion that exceeds the tolerance level, it will alarm. The alarm will continue until you either press the Grove button - which resets and reactivates the device or you can press the Reset button on the Base Shield to Stop monitoring for motion.
//Motion Detector Alarm - Written by ScottC on 2/08/2012
//Global Variables and constants constint buttonPin = A0; // button Pin connected to Analog 0 constint buzzerPin = A1; // buzzer Pin connected to Analog 1
//Accelerometer Pins constint x = A3; // X pin connected to Analog 3 constint y = A4; // Y pin connected to Analog 4 constint z = A5; // Z pin connected to Analog 5
//Alarm LED constint ledPin = 8; // LED connected to Digital 8
int tolerance=20; // Sensitivity of the Alarm boolean calibrated=false; // When accelerometer is calibrated - changes to true boolean moveDetected=false; // When motion is detected - changes to true
//Accelerometer limits int xMin; //Minimum x Value int xMax; //Maximum x Value int xVal; //Current x Value
int yMin; //Minimum y Value int yMax; //Maximum y Value int yVal; //Current y Value
int zMin; //Minimum z Value int zMax; //Maximum z Value int zVal; //Current z Value
void setup(){ //Begin Serial communication Serial.begin(38400);
//Initilise LED Pin pinMode(ledPin, OUTPUT);
}
void loop(){ // If the button is pressed, initialise and recalibrate the Accelerometer limits. if(analogRead(buttonPin)>500){ calibrateAccel(); }
// Once the accelerometer is calibrated - check for movement if(calibrated){ if(checkMotion()){ moveDetected=true; } }
// If motion is detected - sound the alarm ! if(moveDetected){ Serial.println("ALARM"); ALARM(); delay(1000); }
}
//This is the function used to sound the buzzer void buzz(int reps, int rate){ for(int i=0; i<reps; i++){ analogWrite(buzzerPin,900); delay(100); analogWrite(buzzerPin,0); delay(rate); } }
// Function used to calibrate the Accelerometer void calibrateAccel(){ // reset alarm moveDetected=false;
//End of calibration sequence sound. ARMED. buzz(3,40); printValues(); //Only useful when connected to computer- using serial monitor. calibrated=true;
}
//Function used to detect motion. Tolerance variable adjusts the sensitivity of movement detected. boolean checkMotion(){ boolean tempB=false; xVal = analogRead(x); yVal = analogRead(y); zVal = analogRead(z);
// Prints the Sensor limits identified during Accelerometer calibration. // Prints to the Serial monitor. void printValues(){ Serial.print("xMin="); Serial.print(xMin); Serial.print(", xMax="); Serial.print(xMax); Serial.println();
