LED Light


Cort's Corner -> LED Light


This project is for a simple LED touch light with dimming capability. Here I will concentrate on the voltage regulation circuitry, while the actual construction of the torch light body and wiring of LED is left to the imagination of the readers.

Voltage Regulation

If you have read any tutorials on wiring LEDs, you should already know that you need to control the voltage supplied to an LED. Too little and the LED won't light, too much and the LED gets damaged. Most tutorials on LED also teaches you how to control the voltage by using resistors. Besides using resistors, you can also use a linear voltage regulator or a switching voltage regulator. There are other ways as well, but I will not cover them here.

This project uses a 34063 switching voltage regulation IC for voltage control. Dimming is achieved using a 555 timer to pulse the output power at ~22% duty cycle. The pulses occurs at 120Hz, fast enough to create a dimming effect with no perceivable flicker.

Schematics

LED Light Schematics
The Eagle schematics and board layout file is available here.

Components

Nearly all my components are bought through Farnell-Newark InOne. Within Singapore delivery is fast, and free for purchases above SGD$30.

These are the components for the voltage regulator part:

That's it for the regulator portion, the rest of the components are for the dimmer circuitry. It uses a 555 timer on bi-stable mode, running at ~22% duty cycle and 120Hz.

Misc parts: