After reading this nice tutorial I thought I'd post an instructable to show everyone how I accomplished making myself a few tap lights with a delayed turn-off. My wife always forgets to turn lights off and I knew I had to install these in our closets with a auto-off feature! For my setup I used the following parts, you can play with the capacitor and resistor to adjust the delay in turning off the LEDs. This setup will keep the LEDs on for about 3 minutes before they get too dim to be usable.
First off, let me give credit for the inspiration for this project. I had seen this article
posted a few weeks back while reading through my RSS feeds by Dane Kouttron. Fantastic article and he even explains the principals behind this very simple circuit! http://transistor-man.com/lampfade.htmlHere is what you are going to need:
1. (1) 100uF Electrolytic Capacitor
2. (2) 1M Ohm 1/4W Resistors
3. (3) Super bright white LEDs
4. (2) 68 Ohm 1/4W resistors (depending on your LEDs) Do the math for the resistance needed!
5. (1) 2N7000 N-CH Mosfet
6. (1) 12mm square momentary switch. Normally off.
7. (1) Tap light of your picking! I've listed the one I used.
8. A small piece (~4 inches) of wire.
9. Solder, soldering gun pliers, wire cutters, third-hand and about 20 minutes.
I strongly reccomend you check the prices at www.taydaelectronics.com
for parts! I have ordered from these guys many times and I get my order quickly and accurately every time. They are located in THAILAND so shipping to US is about 2 weeks.