Magic Lamp - You have probably seen "magic lamp" circuits in which an ordinary incandescent bulb is lit
by a match. These circuits rely on a hidden temperature or light sensor and are not particularly interesting. I
decided to make a magic lamp, . . . [Copyright © 1998 Wenzel Associates, Inc.]
Mains Operated
Christmas Star - . . .
Make a Joule Thief - It's a
little wisp of a circuit that allows you to drive a blue or white LED from a low voltage. Normally, if you want
to light up a blue or white LED you need to provide it with 3, 3.5 V, like from a 3 V lithium coin cell. But a
1.5V battery like a AA cell simply will not work. But using the Joule Thief, it works like a charm. Not only does
it work with a brand new battery, but it works until the battery is nearly dead-- down to 0. 3 V. That's well
below the point where your other toys will tell you the battery is dead, so it can steal every last joule of
energy from the battery (hence the name). To learn how to make one, watch the video, which is available in a
variety of formats. . . . [Evil Mad Scientists Laboratories]
Make your own LED Headlamp - I have submitted here my process for constructing an LED headlamp. I originally attempted to
fit the battery holders for 3 AAA cells along with a tiny PC board for the three LEDs and current limiting
resistor all in a tiny altoids tin. No go. I ended up buying a 3 cell holder with switch from Mouser electronics,
gluing an elbow/ball joint pivot from a desktop pen set I had pieces from to that battery holder, then bolting
the pivot to a Walgreens tiny mint tin (the sugar free ones come in a small oval shaped tin). The LEDs . . .
[Contributed by: John Evans]
Making an Amplified Color Sensor from an LED
and an Op Amp - . . .
Marx Flasher - File contains several designs, please scroll to find this circuit. Here is a strange-looking
flasher that uses an unusual form of the Marx high voltage multiplier. The traditional Marx multiplier uses spark
gaps to repetitively charge capacitors from a high voltage supply (in parallel) then to suddenly connect them in
series to generate a much higher voltage, near N times the supply voltage where N is the number of capacitors.
This multiplier uses Lumex gas tube transient suppressors (GT-RLSA3230D) as the spark gap, providing reliable and
repeatable triggering at about 250 volts (much lower than the typical spark gap). The 120 volt line voltage is
rectified and doubled to provide enough voltage to trigger the suppressors and to reduce the required number of
stages. . . . [Charles Wenzel (unless otherwise noted)]
Matrix LED Display - A mini display using an array de 5x24
LEDs using Microchip PIC 16F628. . . . [Jose Pino designer]
Measure Zener Voltages and Test LEDs - 06/10/10 EDN Design Idea You can use this circuit to measure zener voltages as high as
40V. To measure a zener diode's breakdown voltage, you need a dc voltage source whose voltage exceeds that of the
zener voltage. In Figure 1, resistor RSER provides voltage drop between VIN and VZEN. In any case, VIN should
exceed VZEN. Resistor RSER must provide current, IZEN, that can keep the zener diode in reverse breakdown. That
is, the current must be more than IZEN-IZENMIN and less than IZEN-IZENMAX. You also need to consider the current
that flows through the load. Otherwise, VZEN will be unregulated and less than the nominal breakdown voltage.
Also, the power that the zener diode dissipates should not exceed the manufacturer's specifications. Except for
the value of IZEN-IZENMIN, all necessary data appears in zener-diode data sheets. . . [by Vladimir Oleynik,
Moscow, Russia]
MEET BLINKER-blinking LED's - Our BLINKER has many applications; fill your party with blinking BLINKERS. Mount the BLINKER
on your bicycle so you'll be more visible and have a safer ride. Mount it on the car dashboard as an alarm
flashing light imitator. Or mount it on your room door (i. e. please do not disturb). Place BLINKER anywhere
you’d like to draw attention and a smile. The unique small design will allow you to mount it almost anywhere.
Operate it with 9V battery 12V car battery, via two 1. 5V batteries, or via one of our battery simulator kits. .
. . [Kit from Elich Industrial Development, Corp]
Message Wand - The message wand is a good PIC introduction as it is a simple project yet illustrates many
aspects of the PIC usage. Used at night, the wand is swung around above the head, and to onlookers spells out a
short message in the air using flashing LEDs. It could also be used with a handle and spun round like a
traditional soccer rattle (can you still get those?) though great care must be taken if you do this. PICs have
been popular with hobbyists for several reasons: The development tools are free, cheap programmers are available,
and they come in good old fashioned DIP packages that you can solder to without a microscope! They are also
extremely versatile of course! The message wand uses a mid-range PIC – the PIC16F627. . . . [Karen's
Microprocessor Projects]
Microcontroller drives logarithmic/linear dot/bar 20-LED display - 01/18/07 EDN Design Idea Do-it-yourself analog-to-LM3914 display driver offers user
programmability. . . [by Dhananjay V Gadre and Anurag Chugh, Netaji Subhas Institute of Technology, New Delhi,
India]
Mini Strobe Light using LED - adjustable for flash rates between40 Hz and166 Hz, based on555 Timer. . . [Sunamura
Kazuhiro]
Miniature
Lighthouse Light Simulator - The circuit I came up
with is shown below. It uses two dual low power op Amps. The first two devices form a classic oscillator circuit
whose output is a triangle waveform signal. That signal is routed to a current regulator circuit, which converts
the triangle voltage signal to a triangle current signal through the lighthouse LED. A third op Amp generates
pulses timed so they occur at the peak of the triangle waveform. The result is a LED, which gradually grows
brighter, then flashes even brighter before dimming again. This should produce a light, which simulates a
rotating lighthouse light . . . [Circuit Solution by Dave Johnson P.E., 05/07/06]
Miniature Surface-Mount LED Ring Light - Ring lights provide shadowless all-around lighting that is particularly useful for close-up
work such as macro-photography and circuit-board inspection with a magnifying glass. This project also includes
instructions on soldering surface-mount electronic components and machining a circuit board into a ring
(round/circular/donut) shape. . . . [Robot Room website]
Mini-Beacon miniature programmable
LED Flasher that is based around a PIC12F629 microcontroller - . . .
Model Airplane Wing Tip
Flasher - The circuit below is designed to flash two
white LEDs mounted at the wing tips of a model airplane. The flasher unit is powered by a 4. 5v supply made of
three AA or AAA 1. 5v alkaline battery cells. The average current is about 2ma so a set of batteries . . . [Hobby
Circuit designed by Dave Johnson P.E., 10/18/09]
Model Lighthouse - This project was designed for a model lighthouse to flash a lamp or LED in a simple
sequence: two flashes of 2s with a short gap of 1s, followed by a longer gap of 5s before repeating the sequence.
A 4017 counter is used to produce the flash sequence and this project includes information on how to adapt it to
give a different flash sequence. . . [Designed by John Hewes]
Model Train
Lighthouse Flasher Revisited - HO train sets often
have authentic looking scale model homes and buildings. A while back someone asked me to design a flashing LED
light, which he could mount inside a model lighthouse and have it operate so it would appear to rotate and flash.
I designed a working circuit but I was never pleased with the results. I’m still not 100% pleased but the
revised circuit below seems to operate a bit better than the older circuit. … [Hobby Circuit designed by Dave
Johnson P. E. , May 2012] . . . [Hobby Circuit designed by David A. Johnson P.E., 12/20/12]
Modified LED Night Light - I bought some night lights a few months ago from Walmart here in Denver. The devices were
made by Elumina Lighting Technologies Inc. (www. eluminalighting. com) , their model LED-6200A. I think I paid
about $15 for a pack of three lights. I wanted a light . . . [Hobby Circuit designed by Dave Johnson P.E.,
05/21/07]
Monolithic Converter Drives High Power LEDs - DN376 Design
Notes (Linear Technology). . . [Linear Technology]
MSP430 Interface to TPS60250 via I2C Master Software - LED
lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED
lighting designs. LED lighting customers seeking the latest in innovative and affordable LED lighting solutions
can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless
and wired interface control and embedded processors. LED designers have the option of not only controlling the
power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing
system cost. . . . [Texas Instruments App Notes, 1-May-08]
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