Because there is a semiconductor/chip inside the sensor, it must be powered with 3 - 5V to function. Contrast this to photocells and FSRs where they act like resistors and thus can be simply tested with a multimeter.
Here we will connect the detector as such:
- Pin 1 is the output so we wire this to a visible LED and resistor
- Pin 2 is ground
- Pin 3 is VCC, connect to 3-5V
When the detector sees IR signal, it will pull the output low, turning on the LED - since the LED is red its much easier for us to see than IR!
We will use 4xAA 1.5V batteries so that the voltage powering the sensor is about 6V. 2 batteries (3V) is too little. You can also get 5V from a microcontroller like an Arduino if you have one around. Ground goes to the middle pin.
The positive (longer) head of the Red LED connects to the +6V pin and the negative (shorter lead) connects through a 200 to 1000 ohm resistor to the first pin on the IR sensor.
Now grab any remote control like for a TV, DVD, computer, etc. and point it at the detector while pressing some buttons, you should see the LED blink a couple times whenever the remote is pressed