EDIT:Video here.
I get tired of fumbling around in the storage cubbies for my phone or garage door opener. The overhead light doesn't help much either, so I decided to make some hand activated LED lights that go inside the cubbies.
When you stick your hand in there, you interrupt an IR beam that activates an led.
This circuit works perfectly and never draws more than 50mA. All values listed are pretty flexible, but let me know what you find and I can let you know if it will work and what value resistors will give you the best operation.
This requires only 5 components and all can be found at RadioShack. If you can solder a resistor to an LED, you can do this easily.
EDIT: Schecmatics added
IR emitter and detector -
http://www.radioshack.com/radioshack-infrared-led-emitter-and-detector
White LEDs -
http://www.radioshack.com/5mm-high-brightness-white-led-2-pack
LED resistor calculator for the IR emitter and white LEDs -
LED Resistor Calculator
D1 - IR Emitter, 1.3V, 150mA
(1.2-2V, 25-150mA [Any emitter out of an old TV remote will work])
Q1 - IR Detector, C-E voltage 70V, E-C voltage 5V, light current 20-50mA
(make sure the bandwidth range matches D1, ex. 750-980nm [any IR detector from RadioShack will work, but just buy a $2-$3 matched emitter/detector set for D1/Q1 there])
D2, 3, 4 - LEDs, White , 3V, 20-40mA (or any color you want)
R1 - 470 ohm 1 watt resistor
(330-680 ohm, set to D1's required voltage drop [1.2-2V])
R2 - 1000 ohm, 1/2 watt resistor
(330-4700 ohm)
{This value determines both the allowable distance between emitter and detector and LED brightness}
a)
Higher value = gap between emitter and detector can be greater, but LEDs will be dimmer;
b)
Lower value = gap between emitter and detector will be smaller, but LEDs will be brighter. Do not go below 330 ohms.
Total current draw = 22mA (light off), 18mA (light on).
The below picture is correct. Pay attention to the color bands on the resistors and the orientation of the IR emitter, IR detector and LEDs.
Threaded Mode
