I purchased an infrared emitter and detector (radio shack model # 276-0142), and trying to build a remote control button/switch that powers a 3V DC motor (range 1.5-3V). i don't know what other components i will need or how to setup the circuit.

 

Too many questions, not enough info. Try to break it down, and give us a schmatic of as much as you can.

 

You are going to need more than the IR LED and the photodetector pair to control a motor.....

Infrared Emitter and Detector Pair
(276-0142) Specifications Faxback Doc. # 31145

Photodetector

Collector Emitter Voltage.............................................20 V
Collector Current....................................................25 mA
Continuous Device Dissipation at (or below) 25 Degrees C free-air
temperature..........................................................50 mW
Operating free-air temperature range........-40 Degrees C to +80 Degrees C
Storage temperature range...................-40 Degrees C to +85 Degrees C
Lead temperature 1/16 inch from case for 5 seconds...........240 Degrees C


Infrared Emitting Diode

Reverse Voltage........................................................2 V
Continuous Forward Current...........................................40 mA
Radiant Power Output................................................0.5 mW
Wavelength at peak emission.........................................915 mm


Specifications are typical; individual units might vary. Specifications
are subject to change without notice.

You will need a circuit to modulate a signal you are sending (on / off signal) for the transmitter, using a 38khz modulated IR transmitter/receiver would be a good start to google....

You will also need a circuit to interface to the receiver that can handle the motor load... which should also incorporate a 555 timer IC for the on/off delays you want to implement....


go here to Reynolds Electronics for more IR circuits and IC's >>> http://www.rentron.com/PicBasic/RemoteControl.htm

My .02