spokepov questions

SpokePOV kit for bikes

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carmatic1
 
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spokepov questions

Post by carmatic1 »

hey, i was wondering if it was possible to make the spokepov display cylindrical images rather than a flat disc... i am going to mount the LED's away from the board, they will instead be arranged on a large rotating cylinder

also, i am anticipating my project will revolve at low and variable RPM's , so i would like to use multiple magnets to sense the rotation, so instead of one hall effect sensor pulse for each revolution, i would like to have a certain number of pulses to equal one revolution, this would let the led's light up without having to wait for a whole revolution, and it would also be more tolerating to rapidly changing RPM's

i would very much appreciate being able to have more than 4 images... i would like to also be able to control the rate of the image change


lastly, is it technically possible for an auduino to receive data such as new images while it is in use?

carmatic1
 
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Re: spokepov questions

Post by carmatic1 »

okay lets keep things simple

suppose that , rather than mounting SpokePOV radially on a wheel, it is mounted perpendicularly from the plane of rotation
is it then possible to alter the program to accept a square image which gets linearly displayed as a cylinder?

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adafruit_support_bill
 
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Re: spokepov questions

Post by adafruit_support_bill »

It is certainly possible to program a rectangular image into the device. It all looks the same to the spokePOV. I'm not familar with the souces for the existing program, but I imagine that rectangular images would be a whole lot simpler than radial ones.

carmatic1
 
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Re: spokepov questions

Post by carmatic1 »

i am hoping that i do not have to resort to warping my images into circular images to conform to the radial display of the spokepov software

can you give me any clues about the program? like the original author or any documentation

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adafruit_support_bill
 
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Re: spokepov questions

Post by adafruit_support_bill »

I don't know anything about the sources other than they are in C++. But the existing software starts with a rectangular bitmap image and scales and converts it into a radial format for download to the SpokePOV. What you need to do is actually much simpler. You probably just need to scale the image to the right number of pixels and download it.

mtbf0
 
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Re: spokepov questions

Post by mtbf0 »

low rpm may be a problem. so, how slow.

a radio could be used to transmit image data to a display in use. or maybe ir from above the display. this would require a substantial rewrite of the firmware. the device has only 2k of program memory and 128 or 256, (can't recall), bytes of ram. it's not an arduino. it's based on an attiny2313.

what do you want to display? how slow will you be spinning. is it safe to assume that your display will fit into say 90 degrees of a rotation?

carmatic1
 
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Re: spokepov questions

Post by carmatic1 »

thanks for the replies, guys
arduwino wrote:I don't know anything about the sources other than they are in C++. But the existing software starts with a rectangular bitmap image and scales and converts it into a radial format for download to the SpokePOV. What you need to do is actually much simpler. You probably just need to scale the image to the right number of pixels and download it.
ah ok thanks, that is good to know , the software handles the download to the spokepov?
mtbf0 wrote:low rpm may be a problem. so, how slow.

a radio could be used to transmit image data to a display in use. or maybe ir from above the display. this would require a substantial rewrite of the firmware. the device has only 2k of program memory and 128 or 256, (can't recall), bytes of ram. it's not an arduino. it's based on an attiny2313.

what do you want to display? how slow will you be spinning. is it safe to assume that your display will fit into say 90 degrees of a rotation?
yes, the images are going to be mostly vertical, it will repeat at least twice for each rotation
i was thinking that the 2 rows of LED's will be connected by wires to the board and placed on opposite sides of the rotors, this will require the spokepov to operate at least twice the rotation speed... this should compensate for the low rpm somewhat

a live image update system would be ideal, if it is technically possible, or if it is feasible compared to buying something like an Arduino with some form of wireless communication shield... or use the midi standard and this http://www.m-audio.com/products/en_us/MidAir.html which might be more suitable since the attiny2313 is only going to hold 128 bytes , but there needs to be a way to get midi to work with spokepov somehow...




what i am wondering now is if the spokepov can be reprogrammed to do 2 things...

1. to have an arbitary number of magnetic sensor signals per rotation... i have 9 magnets and i would like each row of LED's to display the images an even number of times, so it means that i also need a non-integer amount of signals as well

and

2. to have an adjustable image update rate ... i would most likely need to have the image update much more slowly compared to being on a bike wheel

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