Strange Behaviour from EPIR sensor

Projects General Guidance
1

I have this Zilog EPIR senor that Im trying to incorporate into a robot project of mine. Found some test code online that I am using to make sure I had it all wired up correctly.

The wiring is in accordance to this diagram:

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And finall here is the sample code I am using:

int sleepModePin = 4;
int motionDetectPin = 2;
int alarmLED = 12;
int val;

void setup() {
  //the sleep pin has to be active high to enable detection
  digitalWrite(sleepModePin, HIGH);
}

void loop() {
  val = digitalRead(motionDetectPin);
  //the ePIR sensor is active low so if motion is detected the output is low
  if(val == LOW) {
    digitalWrite(alarmLED, HIGH);
  } else {
    digitalWrite(alarmLED, LOW);
  }
}

It all seems to work fine when Im using an LED. It performs exactly as you would expect, the light turns on when I pass my hand near the motion sensor. However, I do not want to use this to control a light. I planned on using it to make a vibration motor (shown here) shake when motion was detected. Since the LED setup worked fine, I tried doing the exact same setup, but putting the terminals from my vibration motor in the place of the LED (resistor removed of course). With this set up, the motor never vibrates. Im puzzled as to what changed when I went from LED to motor. I made sure the motor was working, I attached each terminal to a AA battery and it did indeed vibrate. If anyone can help me figure out why this motor wont vibrate when motion is detected Id be very appreciative.

2

The Arduino output pin does not have enough power to drive a motor. Use a transistor to "amplify" the power. Look up the playground for hints about driving motors.

3

The motor seems to work fine with the arduino. It's a 3-5V mini vibration motor, not like a servo motor. When I hook it up directly to +3.3V and GND it vibrates as well. Unless what you're saying is that the motor's power draw in combination with that of the ePIR sensor is whats causing the issue. I'll look into that next.

4

It's a 3-5V mini vibration motor, not like a servo motor. When I hook it up directly to +3.3V and GND it vibrates as well.

That does not mean to say you can drive it from an I/O pin without buffering.

The tiny vibra motor in your phone could draw from about 70mA upwards - way more than the absolute 40mA maximum for an AVR I/O pin.

5

FriendlyHobo:
The motor seems to work fine with the arduino. It's a 3-5V mini vibration motor, not like a servo motor.

Spec or datasheet?

6

After looking at the data sheet I suspect you guys are right. At 3.3V it uses 60mA so it's more than likely not getting the juice it needs when I also have the ePIR hooked up to the 3.3V. I'll have to supply it some power from 2 AAs or something with a switch, thanks for the help.