Instructables
Picture of RGBike POV - Open project
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RGBike POV also known as RGB POV for beginners to make at home

This i'ble is in constant update. If you're planning on doing something don't be afraid to drop a question.

I've always wanted a POV for my bicycle, specially a full colour POV capable of displaying text, images and small animations!

There are some cool POVs commercially available.
- SpokePOV from adafruit industries (and its i'ble)
- Monkeylectric's m132s
- Monkeylectric's recentely announced m464q

Unfortunately, the SpokePOV is only one colour, and the m132s, as I understand, doesn't have the ability to display images. Besides, I think these are a little too expensive for something that I will not use often.

So I though I would try to make my own with components I already had around. This way I don't have to spend any more money to try and play with a bicycle POV.

This project features:
  • 16 RGB (Red+Green+Blue) Light Emitting Diodes;
  • Arduino compatibility (Suposedely, I'll have to check that later);
  • Single layer printed circuit board, suitable for home fab;
  • All through hole componentes, suitable for beginners;
  • Hall effect sensor, for image synchronization;
  • Least number of componentes possible;
  • Unfortunately, only one side of the wheel is illuminated (check update).
  • Fits 26" wheels, I haven't had opportunity to try it in 20" and 24" wheels.

This project is also a open project. Anyone who wishes to participate is welcome. The contributions will be added to this instructable and published.

Update: I updated the board, so you can use only one board for lighting both sides of the wheel! But it won't work correctly in both sides for text...


 
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jmaurin3 days ago

I really can't find download button/link....

mbrotcke26 days ago

All other TLC5940 projects require Common Anode, Whats teh diffrence here?

mr817tx3 months ago

if so feel free to contact me @ chadbutler.jj@gmail.com I would greatly appreciate it

mr817tx3 months ago

do you think you can design a device like this for a vehicle on 30 inch rims?? I will pay $$$$

cwunderbar4 months ago

The orange ceramic resonator (Step 4, first pic) what's the frequency? Thanks!!

miaoyu5 months ago

Hey,my name is miaoyu.I
am a student.I am sorry to trouble you.But I
want to ask a question.I am doing an experiment to
study the luminance of each final pixel.My goal is get luminance of
pixels.I set the output file
openexr.I have got the value of standard solar irradiance in 700nm is
1.42666,then I use the conversion coefficient.That is,I converted irradiance to illumiance as my
lightsource input.



My whole code in pov is as below:



#version 3.7;
global_settings{ assumed_gamma 1.0 }
#include "spectral.inc"
#declare SpectralWavelength =700;

camera
{
angle 7.54371
location <camera_x,camera_y,camera_z >
look_at <0,0,0>
rotate <0,-31,0>
right x
up y
}

light_source {<sun_x,sun_y,sun_z>
SpectralEmission(3.99750132)
}

#declare geom_file_name = "pov-xyz.txt";
#declare spec_file_name = "pov-ref.txt";

         sphere
{

<x1-center_x,y1-center_y,z1-center_z>,
1.55
finish {
ambient 0
emission 0
specular ref
}
}

I have read the openexr source ,it says y channel stand for luminance,how can I set in pov ?

Above ia all my code in pov,whether need I set additional  output or statements to get my lumiance output.Beg your help.

Please tell me what program you use to compose and generate color image and animation file. Hex you register in microcontroller ATMega328p ? Plz help to me

noexit11 months ago
I keep reading that the TLC5940 will not support common cathode RGB LEDs, but your instructable says that it has to be common cathode? What are you doing differently to make this work?
Hazard (author)  noexit11 months ago
Oh! I think I got it.

Because here each color is sequentially driven, by controlling the power to each color sequentially in time, you are able to control the brightness independently.

If you power all colours at the same time, you will only be able to control the brightness of all colors (sum of the RGB, white).
noexit Hazard11 months ago
Okay, now that I read further, that's what I'm reading.

Thanks!
Hazard (author)  noexit11 months ago
I don't understand the question.
Where have you seen it as a problem? What do you mean it doesn't support?
I just searched "common cathode TLC5940", and I've seen other examples that it uses common cathode leds.

Maybe TLC5940 has limited sink current abilities. I don't recall. Is that what they mention? But in this application it has been accounted for. Besides, each color is powered sequentially, one at a time.
noexit Hazard11 months ago
Ok, I saw that on adafriut as their reason they only sell common anode RGB LEDs.

http://www.adafruit.com/products/314

"We carry and use CA more than CC because multi-LED driver chips (such as the TLC5940/TLC5941) are often designed exclusively for CA and can't be used with Common-Cathode."

I've seen it mentioned in a few other places too. Maybe it's a case of everyone parroting one source?
apedroso1 year ago
Ola Boa Noite! (vou usar o portugues mesmo)
Estou tendo algums problemas com o codigo! o arquivo bike_pov.zip contem as libraries utilizadas no codigo,mas qual destes arquivo realmente tem o codigo utilizado na gravação? eu tente o arquivo .c mas ele apresenta erros!
''SENSOR_DDR' Was Not Declared in this scope''
Obrigado pela ajuda!
sbrutal2 years ago
did you try to build the board by using, lets just say 64 pin or more microcontroller, i know it would require hell of a lot transistors, but it might shrink a lot size in board
dconnolley2 years ago
nice idea. way out of my range of capabilites, I thought of maybe one improvement. have some sensor like with a magnet. (just like how a speedometor works on a push bike) the whole induction loop thingy.
in order of keeping the image upright perhaps at any given speed. or to adjust image with speed.

Althought I have no idea how that would be accomplished :P
That's exactly how this device functions.
yeah your right I must have overlooked that whilst being distracted by the shiny objects.

okay well an actual improvement might be....
having a contact on the wheel like a copper coated contact disk, so if its 3 wires 3 contact points near the axle (example would be just like slot cars) that way the led light could be the only thing attached to the spokes not big heavy battery packs... if that makes sense. I figure if you had the circuit board on the wheel an it lost contact for a half second it may reset the board or something so just the Led's should be alright.
siddhanth4 years ago
 dude according to what i understand the hall effect sensor makes the circuit function independently/adjusts the POV according to RPM of the cycle tires right...? you have used a simple multispoked bicycle wheel. what about a MOTORBIKE wheel? can the same be achieved on 15'' or 17'' wheels?
Hazard (author)  siddhanth4 years ago
Yes, it adjusts to the RPM of the wheel. But I wouldn't try it on a motorbike. Too dangerous at high velocities.
 One can actually use it on motorbike IF it adjusts to RPM of wheel ;-) one must use a superglue to fix the stuff on the tyre along with electronic components else the stuff will come out in random direction due to torque acting on it...
Actually, you most probably cannot. First of all, never use superglue for that application. Superglue is NOT permanent, you would need to use an epoxy, and get the wheel balanced afterwards at a motorcycle shop.

Also, you are missing a vital point here.., you cannot simply extrapolate based on what you already know. For instance, at those speeds, it is possible that the inherent latency in the system would not allow for the display to refresh fast enough to display the image when you are going 60mph+ for example.

Also, you have no idea whether or not the hall effect sensor will be able to give you accurate reliable readings at those speeds.
T_T_2 years ago
I realize this would require another led driver, but how would someone go about making this for a 48 inch wheel?
ledartist3 years ago
I wish you can provide the schematic in PDF or other image format.
I don't have Eagle.

Here you go.
rgb_pov_single.png

Great! Thanks!

No problem
do you have the board layout in pdf and is there a sub for A3213
skirmish6663 years ago
Hey there, first of all I love the project - thanks for the hard work. I'm wondering if it is possible to modify this project to have multiple synchronised units on each wheel?
Thanks again!
suwarnoh3 years ago
Dear Mr.Hazard,

I truly like to make POV as you did.
I already have AVR ATM8535. But I still don't understand the concept of using sensor in POV circuit. On your project what is the function of hall sensor and to what uC pin do feed it. Please email to: suwarnokaraba@gmail.com.

I am from Indonesia.
dsandu3 years ago
Mr. Hazard,
Please tell me what program you use to compose and generate color image file. Hex you register in microcontroller ATMega328p / ATMEGA168 microcontroller from RGBike POV project.
D. Sandu by comraex@yahoo.com
Thanks!
kiler013 years ago
just to ask, do i have to own the arduino board to do this project? and if yes what is the exact part that i have to have? (i mean there are a few variations of it as i presume)
oaky83 years ago
Im really interested in doing this, but not for a bicycle
I want to mount these to the rim of a car wheel
Would the much high RPM's of the car rim cause problems?

Im not sure if the processor and hall sensor would be able to function fast enough to properly control the LEDs when the car is doing 30 mph or faster.
Maybe some how dividing the input variable of the hall by half would give the microprocessor more breathing room?

i know little about the microprocessor, would it be capable of keeping up with a car travelling 50 - 70 mph?

thanks!
any help would be highly appreciated
DAVID_A3 years ago
did you develop the software?
Hazard (author)  DAVID_A3 years ago
No, unfortunately I never had the time yet.
puenktchen3 years ago
Did yout start to programm a piece of software to convert normal bitmap images into the radial c-code format?
shifty3 years ago
Heya I think this project is great. Would you mind uploading the eagle library that contains the TLC5094? I've tried searching around the web and can't find one. Or is there some way to extract the eagle part from the .brd and .sch files? Thank you!!!

-Noah
Hazard (author)  shifty3 years ago
Hey! Thanks!
There is a way to extract from the files! weee
use the exp-project-lbr.ulp
02JanDal3 years ago
Two questions:

1. What are the values for R5-R7?
2. Can you use 2N2222 instead of PN2222?

JanD
Hazard (author)  02JanDal3 years ago
1. Anything in the range 5k - 15k Ohms works fine.
2. You can, if the pinout is the same.
Sladex3 years ago
How to define R5-R7?
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