How does this work? Lightpaintig Led-panel

What do i need if i only want to build a led-panel wich can be controlled by a laptop?
so i dont need this wifi-thing they bulid just leds blinking when i want them to

What do i need if i only want to build a led-panel wich can be controlled by a laptop?

A good place to start would be to study the hundreds of pervious LED post in this and the previous forum, then ask specific questions on the things that don't work for you.

i didnt bought anything yet i'm just thinking about what i need and what it may cost

i'm wondering how many things an arduino can control? if it is just 14 then it might be problem to controll about 50 leds separated from each other

As far as I know there's no panel involved, just the stick with leds and some creative photography.

There's no movement in the parts where you see "the panel" and you only see it at night. Apparently in one of the shots a car drove by leaving 2 stripes of horizontal lights.

So I guess they just opened the shutter of a photo camera and walked by. When the Leds wouldn't blink you would see only stripes of light instead of the panel.

There are probably several ways of creating such a pole, cheapest and easiest driving a daisy chain of shiftregisters like the 74hc595. Each can drive 8 Leds and chained together you could drive almost as many Leds as you like. Driven by an arduino you could let a laptop control them, depending on your needs a single stand-alone arduino may already be over-qualified for the job.

I must say the end-result looks great and guess all bystanders must have scratched behind their ears seeing a guy like that walk by XD

i wanted to led the leds blink while i’m walking so that maybe letters or so will be on the picture

ok so i need this http://www.sparkfun.com/products/10174
and connect the transistors with the black connectors on the blue platine in order to turn them on and of?

i understand how the method with the the transistors work but i dont really get how a shiftregister works

The first shift register is driven by just three pins of the arduino and has an output too.

That output can drive the next shiftregister, which also has an output for the third.
Should you there for need 80 leds, you “simply” buy 10 of 'm and more or less place them behind each other and you have
the possibility to drive 80 leds with just 3 arduino-pins.

Of course it isn’t just as easy as I describe, you’ll need to write the software to drive those three pins the right way.
The tutorial KE7GKP mentions is indeed a good one.

I would, by the way, only buy an arduino and needed parts. When you’re going to use the arduino mainly for this project I guess
an arduino with little memory will already be good enough.

For a pole with 80 leds you need:

1 Arduino 1 5V Powersupply or battery with enough power for all LED and 10 74hc595 shift registers 80 LED 80 150-220 Ohm resistors to limit the current of the LED 1 Breadboard 1 pole Some wires 1 USB-cable fitting your Arduino A little time to assemble the circuit A little time to write the program

That's all.

Korman

may I suggest a TLC5940 , it is a part which I have been researching http://www.arduino.cc/playground/Learning/TLC5940 it drives 16 LED's so you need 5 of them, and they are PWM controlled so you can have different shades of colour but you will have to walk quite slowly otherwise your camera would capture the LED's blinking

I suggested the 74hc595 because he didn't request individual dimming and 16 ports output with a TCL5940 cost 5 times as much as with the 74hc595 .

But both are fine options, the original poster just needs to get started.

Korman

ReinerWahnsinn: i wanted to led the leds blink while i'm walking so that maybe letters or so will be on the picture

Ouch, made a mistake, sorry.

If you want letters, you may need an arduino with some memory.

Displaying an 8x8 bit character, (1 line of 8 leds 8 lines wide) will need 64 bits or 8 bytes memory per character.

Should you want to go for the highest resolution using my example, 80 leds, you'll already use 80 bits (10 bytes) for a line and 80 lines wide would mean 800 bytes for each character. Just the Alphabet and numbers 0-9 would require loads of memory. Upper/Lowercase, numbers and punctuation would require an enormous amount of memory. The laptop could be useful in this case, but... You'll have to be sure sending/retrieving characters won't disturb the timing of Leds turned on/off.

That is of course if... you want the highest resolution, you could also choose to display each "dot" by lighting 5 leds and let it blink 5 times. That would still give you a pretty high resolution of 16x16 dots for each character.

If you want to display letters, drawings, pictures etc..., I'd have a look at POV-examples on the net (Persistance Of Vision).

no no i dont want to build a square it should be a vertical line of led which i drag and photopraph so that a letter appears on the photo

------drag-----------> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sec: 1 2 34 5 6

http://vimeo.com/14958082 like this but here it is done with an ipad and it works pretty good i tried it already but is is not big enough

to start ist this everything i need?

http://www.amazon.com/Arduino-UNO-board/dp/B004CG4CN4

30 dollar

http://www.conrad.de/ce/de/product/407224/WID06W190R9/SHOP_AREA_17444&promotionareaSearchDetail=005

10x0,1euro=1,5 dollar

http://www.led1.de/shop/product_info.php?pName=led-5mm-weiss-12000mcd-10-stueck-p-41&cName=led-5mm-ultrahell-weiss-12000mcd-c-3_17

10 for 7 dollar

http://www.mercateo.com/p/139-9591656/8BIT_SHIFT_REGISTER_SMD_74HC595_Typ_SN74HC595D.html#texas-instruments-8bit-shift-register-smd-74hc595-typ-sn74hc595d-texas-instruments

2 for 2 dollar plus 11,50 dollar shipping

http://cgi.ebay.de/Breadboard-Experimentierboard-Steckboard-1380-Kontakte_W0QQitemZ360267638719QQcmdZViewItem?rvr_id=224165207920&rvr_id=224165207920&cguid=8b58031912a0a0e201910551fd003c59

1 for 15 dollar

total about 67 dollar

is this to much?

Your bill of material an interesting collection of what all can go wrong. You chose UV led, SMD IC and a few other interesting choices. I doubt that you'll be happy with that collection.

Check the German board for better sources of components in Germany.

Korman

May I suggest not to use 74HC595 shift registers? Not enough current…

If you just want ON/OFF control for the LEDs, use something like an MBI5168. It is a shift register with integrated constant current control, which saves you from using all the resistors. I’ve used it for nearly all of my projects and love it. Quite cheap as well.

And if you are indeed in germany, I can send you a few of these chips. Just send me a PM. That saves you from having to order them in the US, postage is much cheaper as well :wink: And please don’t blindly order resistors from C… way to expensive. At least have a look at ‘www.reichelt.de’ and maybe ‘www.segor.de’ for price comparison. 0.11€ for a 1/4W resistor is hilarious.

ReinerWahnsinn:
no no i dont want to build a square it should be a vertical line of led which i drag and photopraph so that a letter appears on the photo

------drag----------->
. . . .
. . . .
. . . .
. . . . . .
. . . . . .
. . . .
. . . .
. . . .
sec: 1 2 34 5 6

In this case during the first Blink all 8 leds are on, during the second one as well. In the third and fourth 2 leds are on and 6 are off, which is still 8 bits info. Ditto for blink 5&6 which are as blink 1 and 2.

Designing a Six could require the next info
1 . . . .
2 . .
3 . .
4 . . . . .
5 . . . .
6 . . . .
7 . . . .
8 . . . .
1 2 3 4 5 6

8 bits for each line and… 6 lines wide, 6 bytes for an virtual (!) 8x6 character.

I know you will just use 1 stick with leds, but to display that H or 6 you’ll still need 6 bytes of info for each using a character 8 leds high and (virtually !) 6 lines wide.

The amount of memory needed is exponential to the number of dots used.
80x60 dots would require loads of memory, you’ll get an incredible resolution, but you could… use 80 leds and still treat them in an 8x6 way though.

I would like to advice you to look around a bit when shopping for electronics.
Maybe it’s because I’m Dutch that I don’t want to spend much, but you really could save a lot of money.

10 74hc595s for a little more as 2 euro…

Breadboard is always nice to have, but… keep in mind that you’re walking, should 1 or two wires get loose, you’ll have a h*ll of a time fixing it on the scene. It’s a good idea to have one though to experiment a little with the set-up, but hot glueing all 74hc595’s, resistors and leds to the stick would probably be my idea. The price seems quite right.

70 dollarcents per led is quite a lot.
3-4 Eurocents a piece is also possible.

Resistors could also be a lot cheaper
1.5 eurocents a piece…

In this case I’ve used 100 Ohm leds, which will dim the leds a tiny bit, but it’s a standard value easily obtainable for almost no money at all.

Finally, I love this one, unfortunately the nr of frames/sec a video camera shoots makes it a bit blurry.

Ladyada (google it) also has quite a lot of people using just a strip of leds to show all kinds of things, check the pov-parts…

A German RC-helicopter-pilot is winner if you ask me…

These examples use video instead of photography, but… the idea is more or less the same.

Keep in mind that you’ll still have to get acquainted with all electronic parts and also still need to program everything, just showing a small message on a photograph may… take quite some time.
As others also told, the 74hc595 isn’t the only option, there are several more.

The amount of memory needed is exponential to the number of dots used. 80x60 dots would require loads of memory, you'll get an incredible resolution, but you could... use 80 leds and still treat them in an 8x6 way though.

Sorry, but this statement is garbage. First, at worst when showing a full bitmap which is saved that way, the amount of memory increases is linear, not exponential. And then, in your fine example, anyone with just a little knowledge of programming would have a font and just remember which part of what characters is about to be displayed now. Or if you have algorithmically defined graphics (eg signal strength bars, charts, patterns), you don't need to save all individual bits, you just need to save what parameter to feed into the algorithm to get the next line of dots. But those shouldn't be a real concern anyway, because that's a solved problem with enough working examples available.

I just fail to see what advantage one might gain by arranging the 80 led in a matrix instead of a long line. If one wanted to shorten the line, better just leave the additional led out instead of putting them next to other led where they have no use.

Korman

Just having looked at the term matrix on wikipedia, I guess you're right Korman. My idea of matrix came from Led-dot matrix, the 5x7 and 8x8 blocks.

Treating 80 leds as just 8, by burning 10 at a time, was merely an idea... to use all leds but keep font size small in memory.