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dc-dc instead of a lot of batteries
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dc-dc instead of a lot of batteries

by casainho on Tue May 20, 2008 11:57 am

Hello :-)

Anyone did try use some DC-DC converter instead of use 6 or 7 1,2v batteries in series?
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by kayrock66 on Tue May 20, 2008 11:49 pm

Not sure what you mean. Each SpokePOV uses 2 or 3 1.2V batteries in series. You can even connect multiple boards together to share one set of batteries.

In this application, its hard to beat the batteries direct.
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by casainho on Wed May 21, 2008 4:13 am

kayrock66 wrote:Not sure what you mean. Each SpokePOV uses 2 or 3 1.2V batteries in series. You can even connect multiple boards together to share one set of batteries.

In this application, its hard to beat the batteries direct.

Sorry - I was thinking in Spoke POV V3 from Ian. Since Ian uses 2 LEDs en series... It's a few batteries. I am trying to make my own POV and I like a lot the Ian approach. I am also trying to estime the power in one or tow batteries and the power used on LEDs and the time I would like to have the system on with a full charged NiMh batteries.

I saw that the firmware for SpokePOV is in creative commons no commercial... does anyone knows If there is some bicycle POV project where code is GPL and have some SVN or CVS?
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by adafruit on Wed May 21, 2008 4:34 pm

casainho wrote:I saw that the firmware for SpokePOV is in creative commons no commercial...


thats a mistake, ive corrected it to attrib-sharealine!

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by casainho on Wed May 21, 2008 5:52 pm

ladyada wrote:
casainho wrote:I saw that the firmware for SpokePOV is in creative commons no commercial...


thats a mistake, I have corrected it to attrib-sharealine!

Well, the source still says: Attribution-NonCommercial-ShareAlike 2.5
http://spokepov.cvs.sourceforge.net/spo ... iew=markup

Do you accept contributions to the code? how is the access to the CVS on SourceForge project page?

About energy use, I am now thinking that SpokePOV is best than the Ian SpokePOV V3, because with just 2 or 3 AA cells we can get power for a lot of time of 20mA LEDs while Ian use LED's in series we need a few batteries to get the 7 volts, even If they are AAA, I prefer to have NiMh AA batteries because I think they have more energy for the space of them, than the AAA.
Since LEDs Vf are near the batteries, there is no need of a dc-dc converter as power loss on resistor in series with LEDs should be small.

The EEPROM on SpokePOV is SPI, thats a need because of the speed of data transfer? - could be used one I2C?

I was thinking in use a ATmega168 to have room for future improvements... so I was thinking in use I2C for the EEPROM, SPI for the Serial to Parallel latchs and USART(RS232) for communicating with PC, and in future it can have an serial AVR-USB or bluetooth-serial.

About animation, I was thinking in have a time for the frame be displayed, before jump to the next... and have always a field saying the next image, so we can say 1st jump to 2nd, 2nd jump to 3rd and 3rd jump to 1st. Since there are EEPROMs with 512Kb or 1Mb and we can display 25 frames per second, we can have a short movie... or am I dreaming a lot? :) -- I do not want display movies but simple animations based on frames.

I already started a project page in code.google but I think I will use almost the same hardware as SpokePOV. I would like to have people contribution on software and firmware, using the SVN. I also think I can write a very well commented C code for the AVR MCU for people learn while looking, hacking :-) -- I really like the Ian SpokePOV V3 documentation!!!
I also want to have tools for Linux development, try to use just free software tools for schematic, firmware and software. Also SMD, SOIC ICs.

In the end I would like to have some shop selling this hardware worldwide, as SparkFun for example.

http://code.google.com/p/bicycleledpov/
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by adafruit on Wed May 21, 2008 10:17 pm

you can download a zip of the firmware from http://ladyada.net/make/spokepov/download.html
i no longer use sourceforge, as it is too difficult to maintain and the project is pretty much complete so there havent been any contributions to maintain

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by casainho on Thu May 22, 2008 5:33 am

ladyada wrote:you can download a zip of the firmware from http://ladyada.net/make/spokepov/download.html
i no longer use sourceforge, as it is too difficult to maintain and the project is pretty much complete so there havent been any contributions to maintain

I don't believe that the project is pretty much complete. I had being reading others versions of bicycle povs and everybody have different things... and everybody wish a kind of USB or wireless communication with PC.

As I said, I have a few ideas that could be improved in the SpokePOV, as the animation(frame times), the communication with PC, better commented code for easy understanding and hacking, better PC software support as GNU/Linux version.

IMO, having a closed development(without use CVS and let others help improve) the project will not involve, grow :( -- There is always room for improvements, projects, life, are never complete.

As for hardware production, I believe there is need to have a stable version but that shouldn't limit the new ideas, hacks, improvements...

I have two options, or create my own project and reuse the hardware + firmware + software of the SpokePOV or I contribute to the original project, but, being like a closed and "pretty much complete" project just let me go for the first option.
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