Hacks and Mods: LED Light Box

For beginners, it is
their first project that gives them a boost. And in order to get that,
it is always necessary to make sure that the project that you select is
really useful. One such project is the RGB light fader. This is quite simple and can be done easily by a beginner. Read on to know more about this.

About 20 LEDs are required here. Start by wiring all the LEDs and connecting it to a breadboard. This is quite a tedious process and takes quite a lot of time.

The next step is to make the power board. Quite a lot has to be done to drive all the LEDs using a single PWM channel. So to compensate for this, a multiplexer IC is used. A few voltage conversions may be required in such a case.

As mentioned earlier, a single PWM is used
to control three different channels. The MSP430 is used to switch
between the different channels. This gives the impression that there are
three individual channels. There may be some issues with the flicker,
but this may not be a show stopper problem.

The source code for running the circuit is quite complicated . About
12 different modes are present here and switching between the various
modes is done using a single push button.

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Temperature Candle Using LED

based projects require a lot of skill and hence only experienced
circuit designers try out these circuits. But there are also a few
circuits in this genre that can be done by amateur electronic hobbyists.
The temperature candle is one such circuit. Read on to know more about

The hardware components that are required to build this circuit are listed below:

  • Microcontroller
  • Temperature Sensor
  • PCB

The circuit design is pretty simple. The LED
is made to flicker by the microcontroller and the color is based on the
ambient temperature at that point. The temperature of the room can be
known by observing the color of the LED.

The temperature value is obtained in degree Celsius. This value is received as a result of pressing the reset button on the PCB.
This value can also be obtained by providing power to the device. Once
the device is powered up, the change in temperature is indicated. The
blue LED is triggered for a temperature increase of 10 degrees. The red LED is triggered for a temperature increase of a single degree.


Suppose, the ambient temperature is 23 degrees celsius, The circuit works in such a way that the blue LED is made to blink twice and the red LED is made to blink 3 times. Soon after this, an orange colored flicker is observed as the LED goes into canfle mode.

Since through hole components are used in this circuit, it is very
cheap to construct and the components can be easily soldered. The
circuit also contains a jack for connecting to a Microchip Pickit 3
programmer / debugger. This reduces the complexity involved in code
modification and download.


Hacks and Mods: Incredibly Illuminated Persistence of Vision LED Clock

Persistence of Vision flashes LEDs during sure moments as it spins, to illustrate formulating a clock above. The PCB blades have been spun around regulating a pc cooling air blower to create this POV clock.

The existence outcome is interjection to bright LEDs
that have been synchronized with a Hall Effect sensor. The house gets
energy wirelessly in between a bottom transformer as well as a curl upon
a board.

The arrangement is ever becoming different as it receives a lot of
inputs from a firmware automatic with 3000 lines of formula. Unlike
alternative clocks, we can essentially tweak a lot of animations as well
as customize a display.



Touch Sensitive Light Dimmer

With IC SLB0586A from
Siemens you can build a simple touch light dimmer circuit that will
allow you to adjust the lamp intensity. Together with a TIC206D triac,
it enables smooth regulation of light intensity from a bulb of 10W –
400W. A coil of 100µH/5A is required to suppress switching noise.

The voltage supply is obtained through R2, C2, D1 and C3 and is
about 5.3V below the network potential. The touch sensor that is used to
drive the IC is connected at pin 5 through two 4.7MΩ resistors, R5 and
R6, in order to ensure user security.

In the adjustable touch lamp schematic we can see three selection
connection , for selecting one of three modes of the IC. When the B
connection is used, the light will always be ON at the last level that
we used. With A or C connection the light will be ON at the minimum
intensity. With B or C, the purpose of regulation is reversed with each

Schematic of the adjustable light with touch sensor

When the sensor is touched for a short period of time (50 – 400 ms), the lamp will be ON or OFF.
If the sensor is touched for a longer period of time it will start the
regulation process. Warning! This touch light dimmer circuit has some
points where lethal 220V is present, please do not try this project if
you are not qualified.



Eight LEDs Make a 100-Division Voltmeter

The circuit in this
Design Idea makes a voltmeter that reads to 0.99V. The idea uses a
counter IC to drive two sets of four LEDs (Figure 1). Each of these two sets represents a BCD (binary-coded-decimal) value. With all of the LEDs off, the voltmeter reads 0V. With all of the LEDs on, the reading is 0.99V. Op amp IC1A generates a predictable voltage ramp

You use op amp IC1B as a comparator to compare the ramp to an input
signal. The higher the input voltage, the longer the output pulse from
IC1B is. You use this pulse to gate free-running oscillator IC2B. A
potentiometer on this multivibrator circuit allows you to adjust the
full-range count. The voltmeter has a maximum input of 1V and uses three
dual-part packages. You make output counter IC3 work as a two-digit
counter by strapping the enable pin of the IC3B part to the MSB (most-significant-bit) output of the IC3A part.

A dual op amp is used to create the comparator function and the ramp
generator. The design also uses a dual 555-type timer chip. You use
IC2A to create the ramp and to reset it and the output counter, and you
use IC2B as a free-running oscillator that drives the counter chip. To
blank the output LEDs when the chip is counting, Q3 disables drive current to the LEDs when IC3 is incrementing. You use IC4 to derive a reference of 2.5V.

Tests of the design use TL084 op amps, but you can also use an
LM358. A top view of the 15×15-hole prototype board shows component
placement (Figure 2a). Figure 2b shows a bottom view of the board, with
the connection and three resistors. You might use flat-green LEDs with the sides painted black or covered with black-plastic sleeves for good visibility.


LED Volt Meter

Here is a Simple LED
Volt meter to Monitor the charge level in Lead Acid Battery or Tubular
battery. The terminal voltage of the battery is indicated through a four
level LED indicators. The nominal terminal
voltage of a Lead Acid battery is 13.8 volts and that of a Tubular
battery is 14.8 volts when fully charged. The LED voltmeter uses four Zener diodes to light the LEDs
at the precise breakdown voltage of the Zener diodes. Usually the Zener
diode requires 1.6 volts in excess than its prescribed value to reach
the breakdown threshold level. When the battery holds 13.6 volts or
more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off.

LED Volt Meter Circuit

LED Volt Meter Circuit Diagram

Author: D. Mohan Kumar
Copyright: electroschematics.com


220V AC Powered Blinking LED

I needed a pulsating
light for a certain signaling. Voltage was 230V. So I decided to make a
simple circuit, consisted of a LED diode, two
capacitors, two resistors, a diac and a diode. Activity of the circuit
is extraordinarily simple. The capacitor charges by the diode and the
resistor. When the voltage on the capacitor achieves 30V the diac
“releases” the electrical tension and the capacitor empties thorough the
diac, LED blinks. Time base is dependent from
the capacitor and the resistor, which is in series with diode 1N4007.
Capacitor must be at least for 40V.

The pulsing LED

The pulsing LED

Schematic of pulsing LED circuit

Schematic of pulsing LED circuit

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The Brightest White LED’s On Earth

US manufacturer Lumileds Lighting has developed a whole new breed of LEDs
– they use new technology, they look quite different and they produce
more light than we have ever previously seen coming from a LED. The new LEDs are branded Luxeon. The manufacturer’s publicity suggests that the Luxeon LEDs
are the start of a lighting revolution – and to an extent we agree.
“Luxeon is today’s brightest solid-state light source, producing 10-20
times the output of a standard LED lamp,”
suggests the company. “With a white source efficacy of 25 lumens /
watt…Luxeon is a realistic source for general and directional lighting.”
Lumileds claims that the LEDs can be
integrated into light fixtures – after all, with a rated life of 50,000
hours (other data suggests “up to 100,000 hours”), the ‘bulb’ probably
never needs to be changed. Their publicity material shows the LEDs
being used for internal commercial lighting and outside architectural
lighting, in addition to emergency and portable lighting.

their amazing light output justice. Here the current to the 1W LED has been reduced, the camera has been placed well off-axis – and bad lens flare has still occurred.” height=”254″ width=”302″>

is almost impossible to photograph either of the Luxeons in action – and
do their amazing light output justice. Here the current to the 1W LED has been reduced, the camera has been placed well off-axis – and bad lens flare has still occurred.


LED Mood Light

This circuit makes a nice lamp that consumes little power, runs cool,
and has an incredibly long lifetime. The lamp puts out a warm yellow
shade of light, the color may be adjusted by changing the number of red
or green LED strings.

Operating Voltage: 12V DC
Operating Current: 80ma approx.

The current flows and the LEDs light. There are 4 series strings of LEDs in this circuit, the resistors limit the current through the LEDs and prevent them from burning up. The resistors were adjusted to get approximately 20ma through each string. Different LED colors will have different voltage drops and resulting current flows. These resistor values will work fine at 12V.

Led Mood Lighting

Led Mood Lighting

The circuit was mounted in a plastic 35MM photographic slide box with a
translucent plastic top (not shown). A piece of perforated board was cut
to fit inside of the slide box, the LEDs and
resistors were inserted through the holes in the board and the wires
were soldered together on the back side of the board. It is recommended
that you use a heat sink on the LED leads while you solder them, LEDs
are very heat sensitive. A length of speaker wire was used to connect
the lamp to the power source. The circuit board was connected to the
plastic box with one 6-32 screw and several 6-32 nuts were used as

None required

Connect this circuit to a 12V battery or power supply, it puts out a
nice glow that won’t affect your night vision too much. You can read by
this light if you use it at close range.

10x green LEDs, T1-3/4 size
9x red LEDs, T1-3/4 size
3x yellow LEDs, T1-3/4 size
2× 100 ohm 1/2 W resistors
1× 56 ohm 1/2 W resistor
1× 62 ohm 1/2 W resistor (can also be 56 ohm, it’s what I had on hand)
1× 1/2 Amp 28VDC fuse
1x Plastic box with diffused (blurry) top, I used a 35mm slide box.
1× 6-32 3/8” screw
2× 6/32 nuts


LED Lighting For Dual-Filament Lamps

Before we describe how it’s done, note that
we recommend that the result be checked as having sufficient brightness
for a stop & tail-light application. That’s because the light output
may be inadequate, depending on the tail-light lens and reflector
assembly – so use any modified lamps with discretion! As shown, an
additional diode (D1) and resistor (68W) provide power from the “tail”
circuit. Alternatively, when the “stop” circuit is powered, the resistor
is bypassed by D2, thus increasing the LED current and the light output.

Modifications to the lamp assembly instructions are as follows:

  • After soldering in the copper tube but before soldering the
    platform board to the bayonet lamp base, the three components inside the
    dotted box must be wired up inside the base.

*The anode leads of the diodes can be soldered directly into the
contacts (“bumps”) on the base (a fine file or glass paper may be needed
to get a nice round shape). Everything must be insulated (use
heatshrink tubing).

The red wire from the Multidisc board is then soldered to the
junction of D2 and the resistor. The black wire is soldered directly the
metal casing of the lamp. We suggest testing the lamp before soldering
the platform board in place. It may be necessary to vary the value of
the additional resistor to get the correct intensity change between stop
& tail modes.