18 LED dimmable lamp

Power this project from sunlight with a CirKits solar power circuit board kit.

---

18 LED dimmable LED lamp

Introduction

This circuit is a dimmable white LED lamp array with 18 LEDs. The lamp brightness is regulated as long as the input voltage is above 10.5V. A low-dropout analog voltage regulator is used for a simple and relatively efficient design. The lamp produces enough light to use as a a reading lamp or a small work lamp.

Specifications

Power Requirements:
Input Voltage: 10.5-16V DC
Input Current: 11-150mA at 12VDC

Theory

The 12V DC input voltage is routed through the 1A fuse and the on/off switch. The 1N4001 diode acts as a crowbar device. If reverse polarity is applied, the fuse will blow and the rest of the circuitry will be protected. Power is sent to the LM2941CT voltage regulator IC. The regulator is wired to produce a voltage range from 5.5V (dim) to 8.3V (bright).The 4.7K resistor across the 1K brightness adjustment potentiometer produces a non-linear brightness adjustment to compensate for the eye's logarithmic brightness perception response. The LEDs are organized in six series groups of three with a 24 ohm current limiting resistor on each group. This arrangement limits the maximum current through each LED group to around 20mA.

Use

Connect the DC input terminals to a 12V source, such as a 12V lead acid battery. Be sure to observe the correct polarity. Turn the power switch on and adjust the brightness adjustment for the desired brightness.

Parts

• 1X LM2941CT low-dropout voltage regulator
• 1X aluminum heat sink
• 1X 1A DC rated fuse
• 1X DC switch
• 1X 1N4001 diode
• 2X 1K 1/4W resistors
• 2X 4.7K 1/4W resistors
• 6X 24 ohm 1/4W resistors
• 1X 1K linear potentiometer
• 18X 5mm white LEDs, 20mA max
• 1X 22uF 16V electrolytic capacitor
• 1X 100nF 25V monoblock capacitor

Here are the Eagle CAD files for the printed circuit board:

• dcledlit2.brd
• dcledlit2.sch

12 Volt LED Knight Rider sparkling

New Knight Rider Board, This Third and Best Circuit.
Both the Circuit Schematic and the Circuit Board are Below

These circuits will give provide a Good Effect, duplicating the Knight Rider Lights, Plus more.




In the First Circuit
By Changing the Values of the resistors on pins 6 and 7, And/Or the Capacitor
on pin 2 of the 555. you can change Frequency.



I suggest you maintain an Aproximate 50% duty cycle.
This will give an Even Rise and Fall.



But reducing down to 25% can give a reasonable effect also!






In the Second Circuit
In the Second Circuit, the range of Frequency Adjustment should be Quite Sufficient as presented.
But the .47 cap can be changed in Value for other frequencies.



This Circuit is Better than my First Circuit above, as the waveform is more symetrical
and the Drive to the LM3914 is a more stable voltage with more current available.



Changes to the Ratio of the 470K to the 1M Resistor can affect both the Frequency Range
as will as the Waveform Symetry. This could create a Sharp Rise and a Slow Decay,
or Visa Versa. Resulting in Different Visual Effects.






In the Third, Newest Circuit,  The Simplest Circuit and Best Yet



The TL082 (Or a TL072 also is OK) Creates an Adjustable Sawtooth Generator.
(It also has a Square wave Output, but it isn't used here.)



The Left and Right LED's are Connected in Series and if this circuit is used on a
12 volt system, and if a person wanted to they could connect 2 LED's for each LED Shown.
Additionally I show the LED's Mounted on the Circuit Board, But they can be wired
OFF Board if So Desired.



1) There is a 1K Pot that adjust the Voltage input to the LM3914.
2) There is a 5K pot that adjust the Output voltage of the Sawtooth Oscillator.
3) There is a 250K Pot to set the Frequency as Desired.
4) Additionally there is a Connection point between Pin 9 of the LM3914.
Joining these together to creates a Bar Display.
5) Substituting an LM3915 or an LM3916 will create a Non-Linear Effect in the Lights.







Circuit:1






Circuit:2







Circuit:3





Circuit:4







Circuit:5

13 Color LED Rainbow Light

13 Color LED Rainbow

(C) G. Forrest Cook February 8, 2005

Introduction

Only a few years ago, the choice of LEDs was limited to IR, red, yellow, and green. The LED manufacturers have been busy extending the spectrum, and filling in the gaps. The latest generation of organic LEDs (OLEDs) has added some dazzling new colors to the spectrum. This circuit uses a set of 13 differently colored LEDs to generate a full color spectrum. The photo does not fully represent the colors generated due to camera limitations. The real-world display is very eye-catching. If you want to "trick out" your PC, this circuit is for you. Forget about those boring blue PC light displays

.

Specifications

Operating Voltage: 6-12V DC
Operating Current: 145ma at 12V DC

Theory

The LM2940T-5.0 low dropout voltage regulator converts the 6-12V DC input power to regulated 5 Volts. It was chosen over a standard 7805 regulator so that the circuit could maintain regulation while operating on a 6V battery. The 1N4001 diode protects the circuit from reverse polarity, if a battery or power supply capable of generating over 1 amp is used, a 1 amp fuse should be installed between the supply and the circuit. The 5 Volts is used to drive each of the LEDs through individual current limiting resistors. The resistor values were determined experimentally for equal brightness. Values are given as examples only, different sources of LEDs will require different resistor values. Resistor selection turns out to be the most difficult part of the circuit's construction. A 100 ohm resistor in series with a 1K pot could be used in place of each resistor if individual brightness adjustments are desired. The table below lists the LED colors and wavelengths

. 

LED Color	Wavelength	Description
Deep Red	700nm	-
Red	660nm	traditional red
Orange Red	635nm	"high efficiency" red
Orange	623nm	also called red orange
Amber	594nm	-
Yellow	588nm	traditional yellow
Yellow Green	567nm	traditional green
True Green	523mn	-
Cyan	501nm	verde green, blue green
Aqua	495?nm	-
Deep Blue	470nm	ultra blue
Powder Blue	430nm	first generation "powder blue"
Violet	410nm	-

Construction

The circuit was built on a prototype perforated board with printed solder pads. The circuitry is hand-wired on the back side of the board. Care should be taken when soldering to the LEDs, a clip-on heat sink should be used while soldering the leads. Care should be taken to avoid zapping the LEDs on the violet side of the spectrum, they are sensitive to static electricity. The circuit board can be mounted on a piece of white hardboard, the white paint reflects the colors nicely.

Use

Apply power to the circuit and enjoy the colorful glow. Do not stare directly into the array at close range for extended periods, some of the LEDs are extremely bright.

Taking The Circuit Further

The spectrum could be extended on both the IR and UV sides. A brief scan through the Mouser catalog indicates the availability of these IR wavelengths: 940nm 880nm, 875nm, 870nm, 850nm. UV LEDs at 400nm, 395nm and 380nm are also available. There are also many LED colors available with wavelengths between the 13 colors shown, the colors selected were chosen for an evenly spaced color spectrum.

An open-collector LED driver circuit could be connected to the negative LED leads for computer control.

The circuit could be used in conjunction with a photo detector for characterizing optical filter curves. Typically, the photo detector output is sent to a logarithmic converter, the log-ratio of the direct light versus the filtered light characterizes the attenuation at a given wavelength.

Parts

Most of the LEDs were purchased from Digi-Key, Jameco, and Mouser. All of the parts were T1-3/4 size, clear packages were used wherever possible. LEDs from different manufacturers may have different focus characteristics. All of the resistors are 1/4 Watt parts. LED part numbers are not available, the rainbow was assembled from parts that were accumulated over several years. Beware that different LED manufacturers use different names for their colors, the wavelength is the best indicator of the color. The Aqua LED is the most difficult part to find,

All Electronics carries them, although the wavelength is unspecified. Another source of colored LEDs is Theledlight, they have a nice Led Color Chart.

I find it somewhat amazing that, to my knowledge, no LED manufacturer has produced a commercial packaging of colored LEDs similar to this project (as of 2006). It would be wonderful if a company would assemble 8 or 10 unique colors into a standard DIP VU meter LED block. It's only a matter of time, I would love to hear about such a part if it ever becomes available.

Source:www.solorb.com

"Mini-Beacon" miniature programmable LED Flasher that is based around a PIC12F629 microcontroller

This project, called "Mini-Beacon", is a miniature programmable LED Flasher that is based around the PIC microcontroller.  This project grew out of an idea and recommendation posted on RunRyder.com.  The Mini-Beacon basically simulates the light emitted from a rotating light beacon such as those used in older police cars and fire engines.  As seen from the observer's perspective, as a real rotating beacon revolves, a dim light slowly ramps up brighter and brighter until a flash is seen (light facing directly toward observer), then as it continues rotating, the light slowly dims out and a pause is observed until it repeats over and over again.  Well, the "Mini-Beacon" simulates this exact effect!  The user can also choose 1 of 12 different flash patterns to be repeatedly displayed.  These patterns include slow, medium and fast rotational beacons (ramp-up & ramp-down speeds), and 3 different selectable flash patterns (single, double and triple flash).  This selection is made by simply shorting a small jumper on the driver board.  This setting is retained in memory so that every time the "Mini-Beacon" is powered up, it will display this pattern. 

If this was not enough, the "Mini-Beacon" also allows you to run it in "free-running" mode (connect battery and it repeatedly flashes), or you can control it (on/off) using a spare receiver channel on your R/C receiver (you can use a transmitter stick or switch).   The setting is accomplished using two small jumpers on the board and is described below in detail.  Additionally, and most likely most important... you can also control the Mini-Beacon using a "Mini-Flash" Controller by simply plugging them together!

Design Criteria Summary:

1) Design a simple, cheap but effective "Rotating Beacon" simulator/driver
2) Design so user can easily choose 1 of 12 flash patterns
3) Lightweight and simple to build (DIY)
4) Circuit powers off of existing R/C servo connector
5) Use servo signal to turn on or off the flashing Beacon effect
6) Powers a bright LED (around 600mA max... a one (1) watt Luxeon looks great!)
7) Listen to customers and their needs!   :)

 
Parts & Tools List ...

1) One (1) PIC 12F629 Chip (preprogrammed with Mini-Beacon code)
2) Two (2) 10K ohm resistors
3) Two (2) 2.2K resistors
4) One (1) Servo Lead/Pigtail wire for Mini-Beacon
5) Four (4) 2 pin header (male) - 3 for Jumpers, 1 for LED/output connector
6) One (1) 2N2222 or PN2222A NPN Transistor
11) One (1) two-row header (mating connector for Mini-Beacon output pins)
12) One (1) piece of heat shrink tubing for assembly
13) Two (2) Shorting Jumpers (one for run mode and the other for programming)

Note: Customer is responsible for supplying LEDs and connecting wires... 
LEDs are sold separately in the DIYRC webstore... CLICK HERE to view them!

Building Instructions...

 

* MINI-BEACON BUILDING INSTRUCTIONS *
 

(Sorry, I am not selling these in kit form... I'd rather build, test and sell)

 

Testing and Operation Instructions...

Download the Mini-Beacon User's Manual below (in PDF format... Adobe reader is required)

* MINI-BEACON USERS' MANUAL * 
 

The web version of the manual is shown below:

The Mini-Beacon controller has a servo cable which can either be plugged into a spare channel on your Radio Control receiver (Rx) or it can simply be connected to a 5-6 volt power source.  Opposite of this servo cable lies a two pin connector (inline with board) that is used to connect your beacon LED.  The onboard output driver/transistor is capable of providing around 600mA to a connected load.  A typical 5mm LED draws 20mA while a 1 watt Luxeon emitter draws an average of 350mA.  3 sets of jumpers/pins located on the Mini-Beacon are used to either set the flash pattern (1 of 12), set the servo control function, or allow the controller to free-run.  First thing you will obviously need to do is connect an LED to the Beacon output pins (see picture above, observe polarity).  Be sure to use the proper series current limiting resistor inline (series) with one of the LED leads (typically 56-120 ohms).
There are two ways you can operate the Mini-Beacon controller.  You can either set it up so it's in "free-running" mode (apply power, and it flashes continuously until power is removed), or you can connect it up to a spare R/C receiver servo channel and control (on/off) the flashing pattern of the beacon using a stick, slider or switch on your transmitter (aka Servo Control Mode).  The Mini-Beacon has two jumpers that allow you to set these two functions (labeled "Servo Jumper" and "Free-Run" on the picture above.  Only one of these jumpers should be connected at one time. 

Servo Control Mode
If you want to be able to turn the beacon effect on & off using your R/C gear, you will need to attach the supplied push-on jumper to the pins labeled "Servo Jumper".  This allows the servo signal from your Rx to be read by the PIC.

Note: No jumper and/or short should be across the "Free-Run" pins.

Now, when you plug the Mini-Beacon into your receiver, not only does it gets its power, but it also reads the servo signal output signal from the receiver's servo channel and either turns on or off the beacon effect.  The PIC is pre-programmed to switch on at roughly 60%.  If you use a switch to control this function, you might have to reverse that channels servo function on your transmitter in order to get it to work to your satisfaction (i.e. configure on/off position of switch).  Also, be sure the R/C channel you are using has its "end-points" set to at least 100% on the transmitter.
 

Free-Running Mode
If you want to allow the Mini-Beacon to run all the time when ever powered up, you need to do two things (referring to picture above):

1) Disconnect any jumper/short attached to the pins labeled "Servo Jumper" if it is connected.

2) Apply a push-on jumper across the pins labeled "Free-Run"

Now, every time you power up the Mini-Beacon, it will begin flashing, and continue so as long as power is applied.  You can still plug the Mini-Beacon into your receiver for power, but the servo control function will not work.

Controlling the Mini-Beacon with your "MINI-FLASH" !You also have the cool option of controlling (on/off) your Mini-Beacon using a channel on your Mini-Flash.  This is accomplished by first setting up the Mini-Beacon so it's in free "running mode" (no jumper across "Servo Jumper", and a jumper across "Free Run" pins).  You can now take the Mini-Beacon servo/power lead and plug it directly into a channel on your "Mini-Flash" controller in order to receiver power when the Mini-Flash channel is active.  Be certain that you plug it on correctly, the black lead should connect to the  top pin on the Mini-Flash, while the red lead connects to the bottom pin on the Mini-Flash.  The white lead on the Mini-Beacon should connect to nothing (hangs down a little below Mini-Flash board). 

(Click on picture to the left for an enlargement of what the Mini-Flash programming software would look like to control the Mini-Beacon).

Now, set up a Mini-Flash channel (#1 in this example) such that all 50 events have a checkmark in every location.  Set the Servo Control for channel #1 such that it is only ON for 0-1/4 throttle ("*---").  Now, when the Mini-Flash channel is High or ON (only between 0 and 1/4 throttle), it applies power to the free-running Mini-Beacon, allowing it to flash its preset pattern.  When the Mini-Flash channel turns off, so does the Mini-Beacon.  You can then set up the Mini-Flash such that the channel events (all 50) are selected or check-marked (left to right), and then you set the servo control for the stick position you want for that channel to activate.  If you are using a switch on your transmitter to control this channel the Mini-Beacon is plugged into, simply set the servo control to "**--".
Cool or what?

Programming & Operating the "Mini-Beacon"...

The "Mini-Beacon" can be programmed to display 1 of 12 different flashing sequence patterns stored on the PIC.  To change the pattern, perform the following steps:

1) Apply power to the Mini-Beacon and be sure it is flashing its programmed pattern.

2) While the pattern is flashing, continuously short the programming jumper (two pins shown towards the top/left on drawing) with either the supplied jumper or a piece of conductive metal (coin, paper clip, screw/nail, etc...)

3) Soon after you short these pins together, you will see the LED glow constantly bright.  While it is glowing steadily, remove the short/jumper and you will see the controller quickly flash a certain number of time before continuing its rotating beacon effect.  The number of flashes seen here indicates the pattern number it is now using and displaying.  The 12 different patterns are shown below:

1)  Slow Ramp-up, Flash, Slow Ramp-down
2)  Slow Ramp-up, Double-Flash, Slow Ramp-down
3)  Slow Ramp-up, Triple Flash, Slow Ramp-down
4)  Med. Ramp-up, Flash, Med Ramp-down
5)  Med. Ramp-up, Double-Flash, Med. Ramp-down
6)  Med. Ramp-up, Triple Flash, Med. Ramp-down
7)  Moderate Ramp-up, Flash, Moderate Ramp-down
8)  Moderate Ramp-up, Double-Flash, Moderate Ramp-down
9)  Moderate Ramp-up, Triple Flash, Moderate Ramp-down
10)  Fast Ramp-up, Flash, Fast Ramp-down
11)  Fast Ramp-up, Double-Flash, Fast Ramp-down
12)  Fast Ramp-up, Triple Flash, Fast Ramp-down
 

4) Continue applying and removing the jumper (following steps 2-3) until you selected the pattern you like.  When you are satisfied, you are done!  Every time you now power up the controller, it will use this pattern you have selected.

NOTE: Recent Mini-Beacons I have sold also have another hidden function that allows you to quickly reset the pattern to Pattern #1, rather than having to cycle through all the patterns using the jumper/power numerous times.  With the Mini-Beacon un-powered, connect the programming jumper and then power up the Mini-Beacon.  You will see the LED glow steady and will do so until you remove power, so remove power.  Remove the jumper and re-power the Mini-Beacon.  It should now be set to program #1, regardless of its previous pattern setting.