LilyPad Wrist Band POV

Persistence of Vision (POV) is the illusion  that an image continues to persist even though the image has changed.   In essence, we are taking advantage of the limitations of the brain-eye processing time.  With a camera we can tune our eye for a longer exposure.  The Lilypad POV (row of LEDs) is a fun toy to build with minimal programming and electronic needs.

Step 1: Supplies

 You will need:

1. 8 LEDs (though you can use more or less, probably not less than 6 for a clear image)
2. Lilypad Arduino 
3. Lilypad Power Supply 
4. Conductive thread
5. Velcro/fastener
6. Elastic Band

Comments

[Zovits]

Why did you create the ledPin6-ledPin13 variables?
They don't seem to be used anywhere.
Or is it a way to tell the Lilypad that those outputs are used to power LEDs?

[quasiben]

 You're right.  I was using those variable in a previous version of the code.  I will take them out and repost.  Thanks!  For what it's worth, I am telling the Lilypad to use pins 6-13 as output using the following code:
int ledPinArray[8] = {6,7,8,9,10,11,12,13};

for(int i = 0; i < 8; i++){
   pinMode(ledPinArray[i],OUTPUT);
}

[rashope]

Thanks for posting such a great tutorial! I am using the LilyPad USB, which has a different numbering on the pins. I have succeeded at blinking all the lights, by changing the values in the array as such:

int ground = 2; // LED connected to digital 2 "ground"
int ledPinArray[8] = {A5, A4, A3, A2, 11, 10, 9, 3};

But when I run the rest of the program, I have only two leds blinking... I am working on understanding the loop, and I think the problem is that the ledPinArray variable isn't used in the digitalWrite command in the printWord function... and since my pins are not all numerals, this is failing for me. Can you help me get my head around how the PrintWord function should look using the ledPinArray variable?  Thanks!

[ugly]

I know this is an old post but can I substitute a 3v button cell for the power supply?

[quasiben]

Yes. I hooked up a multimeter and measured a 3mA draw for a button cell (3V CR2032) a LilyPad LED and around a 3mA draw to power a LilyPad. As a large estimate: 8*3mA=24mA+3mA=27mA. The coin cell battery has between 200and 250mAh. So you should be able to power you POV wristband between 7 and 9 hrs continuously.

This is a pretty rough estimate. The current draw will actually change over time and you can't extract all the juice in a coin cell battery. For a great discussion check out: http://www.evilmadscientist.com/article.php/throw/

[monopoly_on_37212]

I can't get any of my leds to flash. Everything else turns on except the leds. did I do something wrong?

[quasiben]

Did you remember to set the last pin as LOW? Do the LEDs turn on at all?

[monopoly_on_37212]

yes, so sorry, I was able to figure it out. Thanks so much! this is a great instructable.

[nedim155]

please could u test this for me


B8(00100000),
B8(00111111),
B8(00000000),
B8(00111111),
B8(00100101),
B8(00100101),
B8(00000000),
B8(00111111),
B8(00100101),
B8(00011110),
B8(00000001),
B8(00000001),
B8(00111111),
B8(00000001),
B8(00000001),
B8(00000000),
B8(00000000),
B8(00000000),
B8(00000000),
B8(00000000)

[Nolava]

 Could this be modified to make "Pixel Poi"? www.feedingthefish.com/index.htm

[Alerick]

Where did you buy your LEDs?

[quasiben]

The leds are from sparkfun (www.sparkfun.com/commerce/product_info.php).

[SirMask]

Great tutorial.  I'm teaching my kids (homeschoolers) electronics, robotics, etc.  Lots of it is new to me, although I did teach MS office, Internet, etc at one point in a traditional school (duh K-12 jail lol).  Anyway, loving this site and your posts.   

[rancidbry]

extremely cool!  I like building circuits, but this might be over my head.

[Kryptonite]

This is a very cool little project, awesome piece! 5/5.

[Ward_Nox]

seems like a geeky and clever way to get a girls attention at a bar

[DemonDomen]

It can't be seen with the naked eye, right? You would only see the flashing lights.

[quasiben]

Actually, you can see this with the naked eye; you just have to move fairly fast.  It does get a bit more difficult the longer the word/image is.  For example, here are some 3D globes www.youtube.com/watch that are spinning really really fast!  And for a great electronics POV kit visit adafruit.com or www.ladyada.net/make/minipov3/

[nevsmom]

Where was this when I was a teenager?! Very cool.

[the_gella]

 I saw this on flickr the other day, so glad you made a tutorial. Great little project!

[sweetsabin81]

very cool

[Bongmaster]

sweet :3