Can't bike fast enough?

SpokePOV kit for bikes

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perchik
 
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Can't bike fast enough?

Post by perchik »

Hi,

I have a single RED SpokePOV kit on my front wheel. I have a road bike with a 26in wheel. I can't seem to get the wheel moving fast enough to even create the illusion of an image. My friend rode by at approx 25mph and it still isn't a convincing image. Do I need a second SpokePOV to create images like in the pictures or is there something I can change in the programming?

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adafruit_support_bill
 
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Re: Can't bike fast enough?

Post by adafruit_support_bill »

The eye responds a little different than a camera. With a camera, you can just stop down and use a longer exposure. For your eyes, you need to view it in the right conditions for the best POV effect. Higher speed and/or more LEDs is only part of it. Your eyes will be more sensitized and the effect will be more visible in darker surroundings.

At 25 mph, your wheel will be rotating at about 5.5 rpm. That's not going to give you Pixar animation quality, but it should be fast enough to give you a decent image in the right viewing conditions. Adding more spoke POV's will give you a better effect.

perchik
 
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Re: Can't bike fast enough?

Post by perchik »

The test we did yesterday was in almost total darkness. I had trouble seeing the image in peak conditions. By trouble I mean that while looking at the wheel, I could only see about a quarter of the image at a time. It took a lot of staring to even pretend that a whole image was there. Is there nothing I can do?

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adafruit_support_bill
 
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Re: Can't bike fast enough?

Post by adafruit_support_bill »


perchik
 
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Re: Can't bike fast enough?

Post by perchik »

So for clarification, on a road bike with a 26in wheel, you can't get a coherent image at all with just one SpokePOV?

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adafruit_support_bill
 
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Re: Can't bike fast enough?

Post by adafruit_support_bill »

It depends on what you mean by 'coherent'. It is not going to be stable like a TV screen, but you should be able to make out the image.

Persistance of vision is a subjective phenomenon, dependent on the viewer as well as the viewing conditions. Many people have no problem with the miniPOV or the POV clocks that move considerably slower than a bike wheel.

perchik
 
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Re: Can't bike fast enough?

Post by perchik »

Right. I get that. On my bike, we {me and 3 other people} could not make out what the image was at all. I get that POV requires a lot of motion, but I feel like my bike wheel is rotating fast enough to handle it.

Am I experiencing normal operation of the system or is there some thing in the firmware I could change to make it display my image better? If I am experiencing normal operation, I'll get another SpokePOV since I already have one. I'm just disappointed that a SpokePOV is virtually worthless alone.

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adafruit_support_bill
 
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Re: Can't bike fast enough?

Post by adafruit_support_bill »

If you are not seeing an image at all, then there is something wrong.

If the image is there but it just doesn't come together for you then the firmware is most likely operating properly. You might try it in a completely darkened room to make sure.

Also make sure that the batteries are fresh. The persistance effect is enhanced with brighter lights against a darker background.

If the system is generating the image properly, the best way to improve imaging performance would be to add another.

perchik
 
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Re: Can't bike fast enough?

Post by perchik »

The LEDs do work, and with a very slow shutter speed we can see that it is in fact making the image. In a dark room we can't get the wheel spinning fast enough by hand for it to look like the image. I guess I'll just strap another one on here to make it better. Thanks for your help

adafruit
 
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Re: Can't bike fast enough?

Post by adafruit »

http://blog.seanbonner.com/2010/05/24/t ... -metblogs/

you need to bike 15mph for a persistant image using one spokepov. its unlikely you can spin a bikewheel by hand that fast.

aegis
 
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Re: Can't bike fast enough?

Post by aegis »

I'm having the same problem and I have three POV's installed on the wheel, scary cause I bought 9 kits in total for some friends and even with three on my bike and running at 31kms/h (19 miles/hour), I was only able to see two letters and not that well. I turned off two POV's, I then turned on an extra one and ran at the same speed at still nothing, just a bunch of fast moving lights but no coherent text to see. I asked a passer by if he could read something without knowing what the text said and after a run he told me that he was able just see two letters, 'LO' out of a text that is supposed to say 'LONDON ATHENS 2010'

Interestingly when I was testing it at home with my hand I could see the text but I was close by, in the street it was a very different story, no satisfactory results whatsoever. Help please.

Thanks

adafruit
 
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Re: Can't bike fast enough?

Post by adafruit »

text is hard for the eye to see - we use large icons - that works a lot better!

AtomCore
 
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Re: Can't bike fast enough?

Post by AtomCore »

I have same problem with my SpokePOV, but I observe "Coherence" image when I driving with 18km/h, when speed up image go blur :) . Have any speed limit coming form Hall Sensor or Code (sorry for my EN)

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adafruit_support_bill
 
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Re: Can't bike fast enough?

Post by adafruit_support_bill »

You might check the alignment of your magnet relative to the hall sensor. I've had bicycle computers that gave erratic readings at high speeds. The fix was to adjust the magnet position so the sensor passed close enough to reliably trigger.

AtomCore
 
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Re: Can't bike fast enough?

Post by AtomCore »

Distance between Hall Sensor and Magnet is 1-2mm, magnet look like coin. I will try to upload FW:1.00 without Blink

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