Salvius robot motion detector

Salvius can now "wake up" if someone walks into the room. This motion sensing feature allows the robot to conserve power by shutting down many of its primary systems and only turning on when someone is in the room with it. This is also a handy security feature considering that if the robot is on you can then connect to it if you have a web enabled device and see what it is seeing. The auto-activation system for Salvius uses an Arduino Uno, a seeeduino relay shield, and a PIR sensor. The code used in the video has been added at the bottom of this page.

Here is a quick demonstration of the new sensor works.

This is the code that was used in the video (above):

// Programmer: Gunther Cox
// Created: 12/25/11
// Last Modified: 12/25/11
// Hardware setup instructions:
// Plug relay shield directly into arduino so that all pins line up.
// Attach 9 volt power supply to GND and +9V plugs of relay shield.
// PIR + to arduino 5V, PIR - to arduino GND, PIR OUT to HUB2 D3.

int relayPin1 = 4; // relay connected to digital pin 4 (D3 on relay shield)
int relayPin2 = 5; // relay connected to digital pin 5 (D2 on relay shield) (not used)
int relayPin3 = 6; // relay connected to digital pin 6 (D1 on relay shield) (not used)
int relayPin4 = 7; // relay connected to digital pin 7 (D0 on relay shield) (not used)
int pirPin = 2;  // choose the input pin (for PIR sensor)
int pirState = LOW; // we start, assuming no motion detected
int val;            // variable for reading the pin status
int pirMode = 0;    // determines if the relay closed already (0 = not closed yet)

void setup() {
  //the time we give the sensor to calibrate (10-60 secs according to the datasheet)
  pinMode(pirPin, INPUT);        // declare sensor as input
  pinMode(relayPin1, OUTPUT);    // declare relay as output
  digitalWrite(relayPin1, LOW);
  digitalWrite(pirPin, LOW);
  pirState = digitalRead(pirPin); // read the initial state
  delay(60000);                   // pause before calibrating

void loop() {
  val = digitalRead(pirPin);  // read input value and store it in val
  if(digitalRead(pirPin) == HIGH) {
    if (pirMode == 0) {
      if (val != pirState) {            //look for 2 inconsistant readings
          // turn main computer on
        digitalWrite(relayPin1, HIGH);  // sets relay1 on
        delay(1000);                    // waits for 1 second
        digitalWrite(relayPin1, LOW);   // sets relay1 off
        pirMode = pirMode + 1;   // relay has been on      

Setup for the PIR motion detector.

About the PIR sensor: