Gadget Freak

From their humble beginnings as little red dots that let the user know if household appliances are switched on, LEDs can now be ultra bright light sources capable of lighting up a room or illuminating the road ahead of a vehicle.

High performance LEDs are now being churned out from many manufacturers around the world like they’re going out of fashion.

Here is a collection of the best LED gadgets that have made themselves home in Gadget Freak.

Our first trip down LED Lane is Bill loved riding his bike at night. He created a 40-LED night light to make sure he could see and be seen on his bike. Bill set up a 55 timer IC to generate a continuous on/off timing cycle to alternatively flash two groups of 20 LEDs. His night light operates on four AA, which will keep the road ahead nice and bright, even on the darkest and chilliest of British nights. You can even extend battery life with a second circuit Bill put together that uses a short duty cycle to flash a single set of 30 LEDs.

DIY electronic projects have always been popular on Gadget Freak. The next post detailed how to build a 7x7 monochrome LED display. The article includes the circuit schematic as well as build instructions and parts list for an easy to build 7x7 LED display. The humble 7x7 monochrome LED display comes into its own when showing animations. The link shows the circuit schematic is quite easy to build. All you need is an AVR, a few transistors, com resistors and some logic to convert RS232 to TTL.

If the next design is any indication, than it seems the stage is set for world domination from the LED.

And it seems white LEDs are leading the charge. Coming so far in a relatively short space of time, white LEDs have already in places that have usually been the domain of traditional lighting displays. Many LED drivers, using both charge pump and inductors, are available to boost the 1.2V to 2.4V available from single and dual-cell NiMH (nickel-metal-hydride) batteries to the 3.6V that thirsty white LEDs require. Thanks to Electronics Weekly, here is the circuit schematic for a white LED driver.

While on the topic of white LEDs, here is a white LED driver that drives as many as four white LEDs from a 3.3V source and adjusts the total LED current from 1 to 106mA in 64 steps of 1dB each. The white LED driver is designed for portable power applications that require white LEDs with adjustable, logarithmic dimming levels.

Who says you can’t have fun with LEDs? This design idea shows you to build a rainbow LED indicator that will signify voltage in an array of colours.

The next post features a fantastic atom expander. The atom expander produces an “exploding atom” effect using 98 LEDs. For a unique (and expensive!) twist on this project, replace the 2N3904s with 2N3055 power transistors on heatsinks and use 12V 500ma incandescent bulbs instead of LEDs.

Another popular entry on Gadget Freak is last year’s article on a rotating LED display. Alan Parekh designed the LED display. His rotating LED display page contains more images and build instructions.

Bill had that weird feeling he was being watched. He designed a circuit that slowly illuminates and fades a pair of red LEDs. It consists of two op amps, one producing a slow rising and falling voltage (3 – 6V) and the other functioning as a voltage comparator. Install it as a skull as a Halloween prop or if spooky things aren’t your thing, use it as a fancy power indicator for a home appliance.

Looking for a cool way of wowing that special someone? Build her a flashing heart (Les wears his silicon on his sleeve) made from LEDs driven by programmable microcontroller. Les’ gadget is simple to build and made from easily-obtainable parts. The unique thing about this design is the LEDs are in an X-Y matrix so each LED is addressable. Diamonds may be a girl’s best friends but gadgets are forever.

And who says you can’t give the humble lamp a nip and tuck? Seeing great potential in a normal, off-the-shelf product, Pete Griffiths designed a circuit he popped into the lamp to give it a new lease of life. His design combines a PIC and three constant buck converters to create the RGB LED controller. This controller drives the high power 350mA LEDs using PWM to control the LED brightness. By driving the red, green and blue LEDs with varying pulse widths the controller can generate up to 16 million colours using fades, strobe and static effects. Making an ordinary lamp a work of art.

(Picture: CP Storm, under Creative Commons Attribution License)