Philipp 56 Posted November 7, 2012 Share Posted November 7, 2012 Or a white hula hoop with discreet LED's installed on the inner side, projecting on the outer side. The hula hoop diffusing the light of the individual LEDs would look awesome, but i'm quite sure that it isn't stiff enough to support the weight of the electronics at high rpm. it would propably bend to the form of an egg at 3600rpm. I didn't even think about the rpm needed to achieve a persistent image. You definetly don't want to spin a hula hoop or a alloy bicycle rim at a couple hundred rpm Even if you could handle the vibrations you would have to put this thing in a display box or a cage to prevent somebody or something putting their fingers in it Unfortunately, LED strip is not going to work, it's too slow. It takes ~60us to update each LED (~30us in fast mode, but I believe those strips are configured to use slow speed,) so to update 180 LEDs you would need 10.8ms. For comparison, TLC59281 has 35MHz data transfer rate, which means you can update (in theory and @16MHz) 180 LEDs in just 270us, so @3600rpm, you can get 60 vertical lines per rotation (120 lines if the strip is all around.) Yeah, i didn't take care of the math behind your project when throwing in the idea with the spinning bicycle rim... Although it is not really achievable with LED strips and a globe of this size spinning at 3600rpm, it would be so damn cool Quote Link to post Share on other sites
abecedarian 330 Posted November 7, 2012 Share Posted November 7, 2012 The hula hoop diffusing the light of the individual LEDs would look awesome, but i'm quite sure that it isn't stiff enough to support the weight of the electronics at high rpm. it would propably bend to the form of an egg at 3600rpm. I didn't even think about the rpm needed to achieve a persistent image. You definetly don't want to spin a hula hoop or a alloy bicycle rim at a couple hundred rpm :grin: Even if you could handle the vibrations you would have to put this thing in a display box or a cage to prevent somebody or something putting their fingers in it ;-) The hoop could be made to withstand ovalling by using an acrylic rod spanning vertically. But, yeah it would have to be spinning quite the speed Less ambitious maybe... a frisbee or frosted acrylic sphere? Quote Link to post Share on other sites
RobG 1,892 Posted December 17, 2012 Author Share Posted December 17, 2012 Just in time for Xmas break. Hopefully my LEDs will arrive soon. cubeberg and bluehash 2 Quote Link to post Share on other sites
cubeberg 540 Posted December 18, 2012 Share Posted December 18, 2012 Looks great RobG! Looking forward to seeing how it comes out. Quote Link to post Share on other sites
RobG 1,892 Posted January 2, 2013 Author Share Posted January 2, 2013 Boards are assembled, now on to the base and the controller. Here's the short assembly video And here's the schematic of a single section cubeberg, bluehash, SugarAddict and 5 others 8 Quote Link to post Share on other sites
timotet 44 Posted January 3, 2013 Share Posted January 3, 2013 awesome!! Quote Link to post Share on other sites
abecedarian 330 Posted January 3, 2013 Share Posted January 3, 2013 Okay... I'm jealous. I have an LCD spouting off the lyrics to They Might Be Giants "Particle Man"... ... and you have your creation. Quote Link to post Share on other sites
RobG 1,892 Posted January 3, 2013 Author Share Posted January 3, 2013 Well, I have 2 more sets of boards available Quote Link to post Share on other sites
cubeberg 540 Posted January 7, 2013 Share Posted January 7, 2013 Do you have a BOM? I might be interested in a set. Quote Link to post Share on other sites
RobG 1,892 Posted January 7, 2013 Author Share Posted January 7, 2013 The half circle: 9 x TLC59281DBQ 9 x 0.1uF 0805 9 x 2.2k (or higher) 0805 The controller: TBD but in my proto globe, I'll be using my F5132 board which is basically F5132 with few external parts. Quote Link to post Share on other sites
luke 9 Posted January 9, 2013 Share Posted January 9, 2013 Not sure if you got my pm but I'll take a set too if its available, Quote Link to post Share on other sites
cubeberg 540 Posted January 9, 2013 Share Posted January 9, 2013 The half circle: 9 x TLC59281DBQ 9 x 0.1uF 0805 9 x 2.2k (or higher) 0805 The controller: TBD but in my proto globe, I'll be using my F5132 board which is basically F5132 with few external parts. Ouch- just realized how much the parts are. I'll hold off for now- spent all my Christmas money already Quote Link to post Share on other sites
RobG 1,892 Posted January 9, 2013 Author Share Posted January 9, 2013 TLC59281DBQ - $0.81 @ Avnet LEDs - $0.27 @ Tayda or $16/100pcs @ Ali 3 PCBs - $7.5 Controller should be around $5-$8 Quote Link to post Share on other sites
cubeberg 540 Posted January 9, 2013 Share Posted January 9, 2013 TLC59281DBQ - $0.81 @ Avnet LEDs - $0.27 @ Tayda or $16/100pcs @ Ali 3 PCBs - $7.5 Controller should be around $5-$8 Cheapest shipping @ Avnet is $8 though. Mouser has them at 0.87 with $5 shipping. Better overall price. I might put in an order - I've been meaning to pick up a few things @ Mouser anyway. Quote Link to post Share on other sites
SirLancellot 0 Posted January 21, 2013 Share Posted January 21, 2013 I'm interested in a set if you have one left. Quote Link to post Share on other sites
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