It's the instantaneous velocity at your points that you're after. That's the first derivative as I recall. Once you know these instantaneous velocities, then the problem becomes arriving at the timing between shutting one LED off, and turning the next one on.
In this way, the LEDS will fool the eye into "seeing" the prescribed instantaneous velocity during each interval. To show yourself how this works, you could simply start out with an intuitive guess at some values, plug them in, and watch it go for a while. At first it may not look much like a real pendulum if the numbers are way off. But then you can make another iteration and try it again, speeding things up some here, maybe slowing it down a little there, etc. After a while, you should be able to get your values pretty much lined up with the real math, but you really don't need to sweat that much at first just to get something going to see it and to try it. Usually, these sorts of things will help you along if you give them a chance, simply by rigging up a crude first approximation enough to watch it work. Then, later on, make it agree with the math. Chuck ---- Original Message ---- From: [email protected] To: [email protected] Subject: RE: [neonixie-l] Math wizzards.... Date: Sat, 22 Feb 2014 14:06:59 -0500 >Hi Chuck, > >It appears you and I have different definitions of fun! :-) > >I do still have the books btw, and I did look it up, found the >formulas, and >realized I don't know what to do with them anymore (It is a function >of age >I suppose; according to the sidebar notes I did know 40+ years ago. >Who'da >thunk....). It would be something like giving me a sonic screwdriver; >I'd >have no idea what to do with that either! > >At the risk of fully exposing myself, I distinctly remember a >university >professor announcing that they recently invented something they >called a >transistor. He warned us not to be distracted by these things, >nothing could >ever be invented that would replace the thermionic valve! As funny as >that >is today, he was not as far off as some may think. Most of us still >use tube >equipped appliances. I do not yet see a practical semiconductor >replacement >for the magnetron in our microwave ovens! > >Bill > > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On >Behalf Of chuck richards >Sent: Saturday, February 22, 2014 1:50 PM >To: [email protected]; [email protected] >Subject: RE: [neonixie-l] Math wizzards.... > >That should be easy enough to do. I don't have the equations >memorized for >this. If it was me attempting to do it, I'd start by grabbing any >and all >math and physics books, and looking up pendulums and periods and >stuff like >that. Sooner or later if you do that, you'll find the equation which >describes the velocity at any given point in the swing. > >Once you know that, then you can go back to your time slices and your >bits, >and then assign them so that they come the closest possible at each >point >that you have defined. > >Grab all the books, blow the dust off, and have fun!! >This is a good one, and congratulations for doing it! >Let us know how it turns out. > >Chuck > >> >> >>---- Original Message ---- >>From: [email protected] >>To: [email protected] >>Subject: RE: [neonixie-l] Math wizzards.... >>Date: Sat, 22 Feb 2014 11:43:44 -0500 >> >>>Yes, I am with you so far. My challenge is to actually put that >>knowledge to >>>work, and find the correct numbers. >>> >>> >>> >>>Cheers, Bill >>> >>> >>> >>>From: [email protected] >>[mailto:[email protected]] On >>>Behalf Of Tidak Ada >>>Sent: Saturday, February 22, 2014 11:03 AM >>>To: [email protected] >>>Subject: RE: [neonixie-l] Math wizzards.... >>> >>> >>> >>>Remember the swing velocity is a (co)sine function. The highest >>speed is in >>>the zero crossing the tops are the left and right ends of the swing >>with a >>>speed zero. >>> >>> >>> >>>eric >>> >>> >>> >>> _____ >>> >>>From: [email protected] >>[mailto:[email protected]] On >>>Behalf Of Bill van Dijk >>>Sent: zaterdag 22 februari 2014 16:31 >>>To: [email protected] >>>Subject: [neonixie-l] Math wizzards.... >>> >>>Hello, >>> >>> >>> >>>I have built a clock controlled by a PIC with 6 numitrons in the >>centre. >>>Around them is a circle of 60LEDs which are programmed to display a >>number >>>of different patterns. I am currently working on a pendulum pattern >>which >>>uses the lower 30 LEDs. I have the software done, the challenge is >>this: >>> >>> >>> >>>A pendulum has a period and an angular velocity that changes from 0 >>at the >>>ends, and maximum in the center, following an equation. In the >>software I >>>currently have 36 time slices (program steps, 0 to 35) in a half >>period of >>>107 clock cycles, for a total of 3852 cycles for one swing (left or >>right). >>> >>> >>> >>>Looking at one swing, my challenge now is to divide the 36 program >>steps of >>>107 clock cycles such that the total number of clock cycles remains >>3852, >>>but the actual number of clock cycles per step are divided such as >>to >>>approximate the equation of one pendulum swing (left or right). >>> >>> >>> >>>Anyone willing to take a stab at this? >>> >>> >>> >>>Bill van Dijk >>> >>>-- >>>You received this message because you are subscribed to the Google >>Groups >>>"neonixie-l" group. >>>To unsubscribe from this group and stop receiving emails from it, >>send an >>>email to [email protected]. >>>To post to this group, send an email to >[email protected]. >>>To view this discussion on the web, visit >>>https://groups.google.com/d/msgid/neonixie-l/002101cf2fe3%242ae9c9c >0 >>%2480bd5 >>>d40%24%40com. >>>For more options, visit https://groups.google.com/groups/opt_out. >>> >>>-- >>>You received this message because you are subscribed to the Google >>Groups >>>"neonixie-l" group. >>>To unsubscribe from this group and stop receiving emails from it, >>send an >>>email to [email protected]. >>>To post to this group, send an email to >[email protected]. >>>To view this discussion on the web, visit >>>https://groups.google.com/d/msgid/neonixie-l/!%26!AAAAAAAAAAAYAAAAA >A >>AAAPDddS >>>hx705MuX20yCpp0vvCgAAAEAAAAPGcVbt7i2JNk%2B0ud8ipvKsBAAAAAA%3D%3D%40 >z >>eelandne >>>t.nl. >>>For more options, visit https://groups.google.com/groups/opt_out. >>> >>>-- >>>You received this message because you are subscribed to the Google >>Groups "neonixie-l" group. >>>To unsubscribe from this group and stop receiving emails from it, >>send an email to [email protected]. >>>To post to this group, send an email to >[email protected]. >>>To view this discussion on the web, visit >>https://groups.google.com/d/msgid/neonixie-l/002d01cf2fed%2452113dd0 >% >>24f633b970%24%40com. >>>For more options, visit https://groups.google.com/groups/opt_out. >>> > > > >$4.95/mo. National Dialup, Anti-Spam, Anti-Virus, 5mb personal web >space. 5x >faster dialup for only $9.95/mo. No contracts, No fees, No Kidding! >See >http://www.All2Easy.net for more details! > >-- >You received this message because you are subscribed to the Google >Groups >"neonixie-l" group. >To unsubscribe from this group and stop receiving emails from it, >send an >email to [email protected]. >To post to this group, send an email to [email protected]. >To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/380-22014262218495852%40 >all2eas >y.net. >For more options, visit https://groups.google.com/groups/opt_out. > >-- >You received this message because you are subscribed to the Google >Groups "neonixie-l" group. >To unsubscribe from this group and stop receiving emails from it, >send an email to [email protected]. >To post to this group, send an email to [email protected]. >To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/003d01cf3001%2454a36a50% >24fdea3ef0%24%40com. >For more options, visit https://groups.google.com/groups/opt_out. $4.95/mo. 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