Difference between revisions of "POV display"

From OpenCircuits
Jump to navigation Jump to search
(yet more POV displays)
 
(31 intermediate revisions by 11 users not shown)
Line 1: Line 1:
[http://zandralemke.pop3.ru/kc-software-video.html kc software video inspector] [http://lorettamotto.pop3.ru/afghani-movie.html afghani movie] [http://magdalenefoland.pop3.ru/collaborative.html collaborative law services] [http://lorrianelesser.iespana.es/mating.html mating] [http://ammiedalessandr.freekong.cn/piano.html mover piano] [http://www.freewebtown.com/cascadefire/preteens-in-lingerie.html preteens in lingerie] [http://susannalabrie.pop3.ru/article/actually-having.html actually having people sex video] [http://trenaclover.iespana.es/auschwitz-death.html auschwitz death camp] [http://graciabonneau.ibelgique.com/styles/chelsea-document.html chelsea document shredding] [http://nerdy05243ptw.freehoxt.com/resources/sustainable-growth.html sustainable growth equation] [http://kennethwaggener.ibelgique.com/mustang-saleen.html mustang saleen body kit] [http://lorrettathornto.pop3.ru/wiki/girls-love.html girls love] [http://nerdy05243ptw.freehoxt.com/resources/middle-school-cheerleaders.html cheerleader middle pic school] [http://lorettamotto.pop3.ru/emma-bunton-maybe.html emma bunton maybe video] [http://curtisbechtold.iespana.es/air-traffic-control.html air traffic control screen savers] [http://lynnettekrach.dostweb.com/ url] [http://lorrettathornto.pop3.ru/wiki/adult-flash.html adult flash video] [http://laveniawilhoit.pop3.ru/pages/alice-ogura-movie.html alice ogura movie] [http://revaschlemmer.ibelgique.com/ebay-selling.html ebay selling] [http://sandeedoucette.pop3.ru/content/linksys-phone.html linksys phone skype] [http://jacustriea.ifrance.com/best-weight-loss.html best weight loss drug] [http://gakohlera.ifrance.com/q/tourist.html tourist] [http://cathleengillan.freekong.cn/description/duran.html duran duran notorious] [http://sheilahyap.pop3.ru/angelas-hunt.html angelas hunt movie] [http://evelynredrick.00page.com/ website] [http://genniesankey.ibelgique.com/chatte.html chatte] [http://www.freewebtown.com/cascadefire/tile-installer.html tile installer] [http://akikomessmer.iespana.es/html/3-close-combat.html 3 close combat] [http://ammiedalessandr.freekong.cn/high-speed-internet.html access high internet speed] [http://leonasharer.ibelgique.com/library/autumnal-equinox.html autumnal equinox dates] [http://laserradiation.freehoxt.com/health-insurance.html health insurance individual] [http://francesshamblin.freekong.cn/blog/matthew-fox.html matthew fox] [http://kennethwaggener.ibelgique.com/accommodation.html accommodation toodyay western australia] [http://gakohlera.ifrance.com/q/lillies.html lillies] [http://www.freewebtown.com/theshywolf/neverwinter-nights.html neverwinter nights walkthrough] [http://nerdy05243ptw.freehoxt.com/resources/hechtscom.html hechts.com] [http://rosanabalzer.pop3.ru/view/ally-aj-video-do.html ally aj video do you believe in magic] [http://www.freewebtown.com/naryu/data/fiberglass-septic.html fiberglass septic tanks] [http://harmonystrum.iespana.es/data/question.html interview question] [http://www.freewebtown.com/cascadefire/wells-cargo.html wells cargo] [http://tegeer.ifrance.com/new/apocrypha.html apocrypha] [http://laserradiation.freehoxt.com/swollen-armpits.html swollen armpits] [http://lorettamotto.pop3.ru/ashley-invisible.html ashley invisible simpson video] [http://lorrettathornto.pop3.ru/wiki/american-nurse.html american nurse credentialing center] [http://cordiacromwell.ibelgique.com/blog/investing-in-indian.html investing in indian stock markets] [http://rosanabalzer.pop3.ru/view/elephant-movie.html elephant movie clips] [http://tegeer.ifrance.com/new/fucking-mature.html mature woman fucking younger woman] [http://magdalenefoland.pop3.ru/incest-stories.html incest stories xxx] [http://lorettamotto.pop3.ru/eminem-video-clip.html eminem video clip just lose it] [http://www.freewebtown.com/naryu/data/quantum-fireball.html quantum fireball] [http://rosanabalzer.pop3.ru/view/jungle-king-video.html jungle king video game] [http://laveniawilhoit.pop3.ru/pages/alex-by-i-movie.html alex by i movie proyas review robot] [http://www.freewebtown.com/naryu/data/redmond-delivery.html redmond delivery service] [http://jammiefiller.iespana.es/topic/medical-expense.html medical expense reimbursement] [http://marcelleashford.freekong.cn/text/garage-floor-protectors.html garage floor protectors] [http://sandeedoucette.pop3.ru/content/news-bins-pro.html news bins pro] [http://marinareichenba.ibelgique.com/articles/thadani.html thadani] [http://gilmasutcliffe.freekong.cn/resources/croquet-set.html croquet set] [http://genniesankey.ibelgique.com/mustang-horse.html mustang horse] [http://donnamarlar.iespana.es/ares-music-download.html ares music download] [http://griseldamoy.ecv.vg/web/internet-scavenger.html hunt internet scavenger] [http://magdalenefoland.pop3.ru/alvin-chipmunks.html alvin chipmunks] [http://www.freewebtown.com/shiraikirei/view/entrepreneur.html entrepreneur online] [http://genniesankey.ibelgique.com/retirement-services.html retirement services] [http://lorettamotto.pop3.ru/korean-movie.html korean movie sad sonata] [http://sheilahyap.pop3.ru/exploited-moms-free.html exploited moms free video] [http://trenaclover.iespana.es/plastic-coils.html plastic coils] [http://berthahallum.pop3.ru/blog/attacked-bull.html attacked bull by cat pit video] [http://holoaddict.ecv.vg/rebel-yell.html rebel yell] [http://zandralemke.pop3.ru/adult-asian.html asian adult movie download] [http://lorrettathornto.pop3.ru/wiki/presentations.html foundation presentation unleashed unleashed window wpf] [http://jammiefiller.iespana.es/topic/monkey-coloring.html printable monkey coloring pages] [http://lorrettathornto.pop3.ru/wiki/666-mp3.html him your sweet 666 mp3] [http://www.freewebtown.com/theshywolf/aisle-runners.html aisle runners] [http://zandralemke.pop3.ru/jeux-video-en.html jeux video en ligne] [http://lorettamotto.pop3.ru/kris-dayanti-video.html kris dayanti video] [http://zeldagallucci.iespana.es/baby-shower-gift.html baby shower game gift idea] [http://elsiecosper.iespana.es/articles/elettrostimolatori.html elettrostimolatori compex] [http://mugollih.ifrance.com/comments/joshua-bell.html joshua bell] [http://francesshamblin.freekong.cn/blog/mexico-vacation.html mexico vacation tours] [http://hattiewaldrep.freekong.cn/articles/grove-crane.html crane grove sale] [http://rosanabalzer.pop3.ru/view/air-lighter-navy.html air lighter navy than video] [http://lorrettathornto.pop3.ru/wiki/see-through-bikini.html bikini micro see through] [http://sheilahyap.pop3.ru/aankh-bollywood.html aankh bollywood movie] [http://gialfrey.ifrance.com/articles/caroline-dhavernas.html caroline dhavernas] [http://krystenminnick.iespana.es/library/casino-card-game.html casino card game] [http://susannalabrie.pop3.ru/article/audio-car-dvd.html car audio video dvd] [http://lorinavanguilde.ibelgique.com/data/puppet-seattle.html puppet seattle theater] [http://martaohare.freekong.cn/q/compatibility-and.html chinese zodiac compatibility] [http://wilhelminabrock.pop3.ru/blog/audio-video-accessory.html audio video accessory electronics] [http://www.freewebtown.com/littleshaga/pages/english-to-spanish.html english to spanish translator] [http://sandeedoucette.pop3.ru/content/nutrasystem.html nutrasystem] [http://elverahardeman.comvision2000.com/ web] [http://laserradiation.freehoxt.com/hawking-technology.html hawking hnc210 net technology vision] [http://gakohlera.ifrance.com/q/adult-twister.html adult twister] [http://sandeedoucette.pop3.ru/content/trazadone.html trazadone] [http://remediosperlman.iespana.es/library/sivasothy.html sivasothy] [http://revaschlemmer.ibelgique.com/childrens-duffle.html childrens duffle bags] [http://zeldagallucci.iespana.es/air-cheat-kirby.html air cheat kirby ride] [http://graciabonneau.ibelgique.com/styles/womans.html womans world magazine] [http://www.freewebtown.com/theshywolf/pain-lower-left.html pain lower left abdomen back] [http://voitovicha.ecv.vg/styles/dreams-and-images.html dreams and images] [http://kinnat.ecv.vg/description/beauty-salons.html beauty salon philadelphia] [http://ncodb.ecv.vg/data/celebrity-hair-styles.html celebrity hair styles] [http://magdalenefoland.pop3.ru/seven-days-in-the.html seven days in the sun video] [http://cordiacromwell.ibelgique.com/blog/anna-marek-teen.html anna marek teen] [http://magdalenefoland.pop3.ru/air-hammer.html air hammer] [http://www.freewebtown.com/cascadefire/justin-boots.html justin roper boot] [http://www.freewebtown.com/naryu/data/eagleware-crack.html eagleware crack] [http://elsiecosper.iespana.es/articles/priceline-airline.html priceline airline ticket] [http://lorinavanguilde.ibelgique.com/data/hanging-oil-lamps.html hanging oil lamps] [http://frauluft.ecv.vg/web/phat-teen-booty.html phat teen booty sex] [http://ammiedalessandr.freekong.cn/kelly-lynch.html kelly lynch] [http://fixnwrtr.freehoxt.com/view/perfect-body.html beautiful body female perfect] [http://www.freewebtown.com/shiraikirei/view/swift-lift-anchor.html swift lift anchor] [http://helenhunsaker.dzaba.com/ sitemap] [http://griseldamoy.ecv.vg/web/true-ryan-cabrera.html true ryan cabrera] [http://sandeedoucette.pop3.ru/content/intake-lt1-manifold.html intake lt1 manifold] [http://nerdy05243ptw.freehoxt.com/resources/met-art-photography.html met art photography] [http://rosanabalzer.pop3.ru/view/aimone-video.html aimone video converter v1.51 serial] [http://remediosperlman.iespana.es/library/monica-brant.html monica brant] [http://donnamarlar.iespana.es/smashing-pumpkins.html smashing pumpkins rotten apples track listing] [http://magdalenefoland.pop3.ru/bargin-shopping.html bargin shopping] [http://genniesankey.ibelgique.com/about-two-thirds.html about two thirds] [http://harmonystrum.iespana.es/data/winbook-si-keyboard.html winbook si keyboard] [http://rosanabalzer.pop3.ru/view/internet-killed.html internet killed the video star lyrics] [http://kapelka.freehoxt.com/topic/omega-watch.html omega watch price] [http://www.freewebtown.com/littleshaga/pages/botch.html botch] [http://genniesankey.ibelgique.com/prudential-insurance.html prudential auto insurance] [http://magdalenefoland.pop3.ru/the-foursome.html bi foursome] [http://hapinker.ifrance.com/movado-watch.html movado watch sports price] [http://laserradiation.freehoxt.com/unchained-melody.html unchained melody] [http://www.freewebtown.com/littleshaga/pages/the-fist-the-whole.html the fist the whole fist] [http://sheilahyap.pop3.ru/jim-carey-new-movies.html jim carey new movies] [http://zandralemke.pop3.ru/abrir-con-copy.html abrir con copy right video] [http://zandralemke.pop3.ru/ernesto-hoost-videos.html ernesto hoost videos] [http://elsiecosper.iespana.es/articles/custom-conference.html custom conference table] [http://antonettesalamo.iespana.es/pet-care-companies.html pet care companies] [http://sheilahyap.pop3.ru/asian-interracial.html asian interracial movie] [http://graciabonneau.ibelgique.com/styles/auctionarmscom.html auctionarms.com] [http://graciabonneau.ibelgique.com/styles/donna-dixon.html donna dixon] [http://crcreek.ifrance.com/pages/santa-anita-racing.html santa anita racing schedule] [http://lanaharton.ibelgique.com/indian-lodge-davis.html indian lodge davis mountain state park] [http://sandeedoucette.pop3.ru/content/guys-undressing.html guys undressing] [http://kylieburroughs.iespana.es/casts.html casts] [http://zandralemke.pop3.ru/japanese-and-asian.html japanese and asian girls movies] [http://tamishatristan.i8.com/ http] [http://kinnat.ecv.vg/description/mls-listings.html mls listings brentwood tn] [http://www.freewebtown.com/naryu/data/youth-baseball.html youth baseball equipment] [http://cordiacromwell.ibelgique.com/blog/argos.html argos online] == POV display ==
+
== POV display ==
  
 
A "persistence of vision display" (POV display) has only a single line of LEDs blinking on and off.
 
A "persistence of vision display" (POV display) has only a single line of LEDs blinking on and off.
Line 21: Line 21:
 
rated in lumens, they're rated in candelas.
 
rated in lumens, they're rated in candelas.
  
 +
----
 
Is it even possible to estimate "lumens" from the catalog information?
 
Is it even possible to estimate "lumens" from the catalog information?
 +
 +
You can use this table to get an approximate conversion from candelas to lumens. Find your LED beam width in degrees, and divide the candelas number in your specs by the cd/lm factor listed for that beam angle to get lumens.
 +
<br>
 +
beam angle cd/lm<br>
 +
beam angle = 5 divide candela value by 167.22<br>
 +
beam angle = 10 divide candela value by 41.82<br>
 +
beam angle = 15 divide candela value by 18.60<br>
 +
beam angle = 20 divide candela value by 10.48<br>
 +
beam angle = 25 divide candela value by 6.71<br>
 +
beam angle = 30 divide candela value by 4.67<br>
 +
beam angle = 35 divide candela value by 3.44<br>
 +
beam angle = 40 divide candela value by 2.64<br>
 +
beam angle = 45 divide candela value by 2.09<br>
 +
 +
Hope this helps.....Dr. Andrew Thomas...
  
 
Do you know what the difference is? Does your flashlight really
 
Do you know what the difference is? Does your flashlight really
Line 51: Line 67:
 
* $1.600 Sunbrite "based LED" SSP-01TWB7UWB12 (441-1007-ND) blue 10 mm 20 mA 7000 mcd
 
* $1.600 Sunbrite "based LED" SSP-01TWB7UWB12 (441-1007-ND) blue 10 mm 20 mA 7000 mcd
 
* $5.980 GM5WA06270A SMT RGB (35 mA red, 35 mA green, 35 mA blue) 3000 mcd (full color range -- apparently used for digital camera flash ?) (Digikey)
 
* $5.980 GM5WA06270A SMT RGB (35 mA red, 35 mA green, 35 mA blue) 3000 mcd (full color range -- apparently used for digital camera flash ?) (Digikey)
* Mouser: hi-power LEDs ( http://www.mouser.com/search/refine.aspx?Ntt=LEDs hi-power ) shows "lumens" directly -- exactly what I wanted.
+
* Mouser: hi-power LEDs ( http://www.mouser.com/search/refine.aspx?Ntt=LEDs+hi-power ) shows "lumens" directly -- exactly what I wanted.
  
 
== further reading ==
 
== further reading ==
Line 57: Line 73:
 
<br>
 
<br>
 
Spoke-POV and propeller clocks links:
 
Spoke-POV and propeller clocks links:
 
+
* A POV device able to display any video file thanks to an embedded Gumstix http://roseace.telecom-paristech.fr/
 
* An entire discussion forum devoted to POV displays http://www.ladyada.net.nyud.net:8090/forums/viewforum.php?f=11
 
* An entire discussion forum devoted to POV displays http://www.ladyada.net.nyud.net:8090/forums/viewforum.php?f=11
 
** In particular, lots of nice pictures http://www.ladyada.net.nyud.net:8090/forums/viewtopic.php?p=4712
 
** In particular, lots of nice pictures http://www.ladyada.net.nyud.net:8090/forums/viewtopic.php?p=4712
Line 66: Line 82:
 
* micro POV display http://positron.org/projects/mpov/ small enough for "glueing it to my shaved head."
 
* micro POV display http://positron.org/projects/mpov/ small enough for "glueing it to my shaved head."
 
* [http://www.rickard.gunee.com/projects/mechscan/dualpic/gamesys.php "Virtual Game System - A game console with a mechanically scanned display."] can play [http://www.rickard.gunee.com/projects/mechscan/dualpic/tetris.php Virtual Tetris] by Rickard Gunée.
 
* [http://www.rickard.gunee.com/projects/mechscan/dualpic/gamesys.php "Virtual Game System - A game console with a mechanically scanned display."] can play [http://www.rickard.gunee.com/projects/mechscan/dualpic/tetris.php Virtual Tetris] by Rickard Gunée.
 +
* [http://code.google.com/p/bicycleledpov/w/list bicycleledpov wiki]: A bicycle visual LED artwork
 +
* [http://popsci.com/povclock Popular Science: "Build It: The Persistence of Vision Wall Clock"] by Dave Prochnow
 +
* Arduino Polar Scanner Project [http://www.desk-nijverdal.nl/ArduinoPOV.html]
 +
* LilyPad Arduino POV Wristband [http://blog.craftzine.com/archive/2010/03/lilypad_arduino_pov_wristband.html]
 +
* "Mechanically scanned display stuff" built by Rickard Gunée [http://www.rickard.gunee.com/projects/]
 +
 +
While most POV displays spin the LEDs in a complete circle, some "wiggle" the LEDs back and forth:
 +
* [http://www.instructables.com/id/Wiggling-clock-LED-Project/ "Wiggling clock (LED-Project)"]
  
 
----
 
----
Line 72: Line 96:
  
 
I think so--[[User:71.234.233.163|71.234.233.163]] 18:06, 22 June 2007 (PDT)
 
I think so--[[User:71.234.233.163|71.234.233.163]] 18:06, 22 June 2007 (PDT)
 +
 +
 +
* "the Orbital Rendersphere"[http://www.orbitalrendersphere.com/][http://beagleboard.org/blog/2013-12-17-project-spotlight-orbital-rendersphere/][http://www.eetimes.com/author.asp?section_id=36&doc_id=1319591&print=yes][http://www.popularmechanics.com/technology/engineering/gonzo/7-builds-we-love-from-world-maker-faire-new-york-2013-7#slide-7][http://makerfaire.com/makers/makerbars-orbital-rendersphere-2-0/], aka the "Big Giant Spinning Limb Slicer".
 +
The Orbital Rendersphere displays images and videos on a four-foot diameter spherical surface using persistence of vision (POV).
 +
Uses a (stationary) Mac Mini to render each frame, and a (spinning) BeagleBone Black to update the LEDs.
 +
Slip ring for power; Wi-Fi to transfer data.
 +
The Orbital Rendersphere displays video at 30 frames per second by spinning four vertical LED strips spaced 90 degrees apart at 450 RPM.
 +
36 feet of WS80211 LED strips.
 +
''(But it looks like 2 complete circles, each 4 ft diameter -- isn't that closer to 25 feet?)''
 +
102x224 pixel resolution.
 +
Several people comment that this is the biggest POV globe they've ever seen.
 +
It's mentioned on p. 1-44 of
 +
John Baichtal, "Robot Builder"[http://books.google.com/books?id=6W4eBQAAQBAJ].
 +
Uses LEDscape[https://trmm.net/Orbital_Rendersphere].
 +
 +
* "Mike Cook's magic wand"[http://www.raspberrypi.org/mike-cooks-magic-wand/][http://www.thebox.myzen.co.uk/Raspberry/Magic_Wand.html].
 +
 +
* Mike Szczys. [http://hackaday.com/2012/09/11/full-color-video-on-a-spinning-pov-display/ "Full-color video on a spinning POV display"]. Built by Félix, Sylvain, and Jérémy at at Telecom ParisTech. highest-resolution POV display I've seen so far. "The time it took us was roughly two months full time". (Does this have a name?)
 +
 +
* [https://www.das-labor.org/wiki/Borg_Ventilator "Borg Ventilator"]. Twice the resolution of the Telecom ParisTech display? A total of 244 RGB LEDs (spread over 4 wings). Has standard VGA input; a Xilinx FPGA and a bunch of support chips convert to circular coordinates. Power through slip rings. Data through non-contact inductive transfer (recycled VCR head). "The speed is infinitely adjustable between 0 and 2500 rpm / min. The FPGA adapts to the actual speed"
 +
 +
* Collin Cunningham. "Ceiling fan POV display"[http://makezine.com/2009/07/23/how-to-ceiling-fan-pov-display/][http://www.instructables.com/id/Ceiling-Fan-LED-Display/]. A single ATMEGA328 and 20 74HC595 shift registers to drive the LEDs. 32 LEDs per fan blade x 5 blades = 160 LEDs.
 +
 +
* Gareth Branwyn. "MonkeyLectric 3D spherical POV display"[http://makezine.com/2010/12/15/dan-goldwater-projects/][http://www.instructables.com/id/n00tron-3D-Spherical-Display-Interactive-Exhibit/]. by Dan Goldwater / MonkeyLectric.
 +
 +
* [http://stargateeggbeater.com/ "The Stargate Eggbeater: Spherical Persistence of Vision (POV) Display Device"].
 +
Mentions
 +
<q>
 +
"we recently decided to move this project to the Raspberry Pi board away from Arduino.
 +
The capabilities and processing power of the Pi are much greater than Arduino.
 +
... [but] ... the refresh rate is too slow, much slower then the Arduino was.
 +
We need some help figuring out how to turn up the SPI speed with our current software arrangement.
 +
...
 +
used Phillip Burgess' at Adafruit 'Light Painting' Python script to process images and output to the LPD8806 http://learn.adafruit.com/light-painting-with-raspberry-pi/software
 +
"</q>
 +
 +
* PixelPi: RGB Pixel Array Driver for the Raspberry Pi[https://github.com/scottjgibson/PixelPi]. Based on Phillip Burgess 'Light Painting' Python script. Apparently supports many different POV hardware displays.
 +
 +
* [http://www.eetimes.com/author.asp?section_id=36&doc_id=1319194&print=yes "POV Deathstar Doubles as Spherical Display"]. Raspberry Pi; Xilinx Spartan-6 FPGA with a DVI decoding core; 360 x 168 pixel resolution; 10 frames/s; 4-phase commutator to deliver 75 watts of power.
 +
** [http://povglobe.wordpress.com/system-overview/][https://www.engineering.leeds.ac.uk/faculty/news/2013/visually-stunning-project.shtml]
 +
 +
* [http://electronics.stackexchange.com/questions/137110/rotating-pov-led-cylinder-using-addressable-rgb-led-strips "Rotating POV LED Cylinder Using Addressable RGB LED Strips"]
 +
 +
''(FIXME: make a separate section for bicycle POV displays)''
 +
 +
* Hazard. [http://www.instructables.com/id/RGBike-POV-Open-project/ "RGBike POV - Open project"]. Arduino compatible; 16 RGB LEDs; hall effect sensor; through-hole components and single-layer PCB for easy fabrication.
 +
 +
* liquidhandwash [http://www.instructables.com/id/Simple-POV-wheel-lights/ "Simple POV wheel lights"] -- elegant and simple. No circuit board. No microcontroller.
 +
 +
* [http://code.google.com/p/bicycleledpov/ Bicycle LED POV] is an electronic LED bar to attach on bicycle wheels. When riding the bicycle, the LED bar will draw with light, text messages and image animations. Free/Open hardware, firmware and software.
 +
* [http://www.makezine.com/blog/archive/2007/03/luscious_electric_delight.html "luscious electric delight"]: source and schematics for a large graphical LED panel. Uses 12 MAX6953 LED drivers; each MAX6953 drives four 5x7 led matrices. The PC generates arbitrary bitmap, sends it out the serial port to a PIC, which translates it to I2C bus connected to all the MAX6953 LED drivers, which update the image at a continuous frame rate of 30fps.
 +
* [https://oldwiki.blinkenarea.org/bin/view/Blinkenarea/BlinkenProjects BlinkenProjects]: projects with lots of LEDs[http://www.kiu.weite-welt.com/de.schoar.blog/?p=206], including a 3D LED array. Wiki: http://wiki.blinkenarea.org/
 +
* [http://www.ianpaterson.org/projects/spokepov20050704/index.htm  Ian’s Spoke POV] Review it.
 +
* [http://www.electric-clothing.com/superpov.html Project: Super POV] Review it.
 +
* [http://www.ladyada.net/make/spokepov/index.html SpokePOV Persistence of Vision for your Bike] Very nice, kit available.
 +
* [http://www.attiny.com/dotmatrix.htm On this page you will find a scrolling LED sign based on the ATtiny2313 AVR microcontroller] Row Column approach with a shift register]
 +
* [http://blog.makezine.com/archive/2007/02/flashing-led-bra.html Flashing LED Bra]
 +
* [http://www.evilmadscientist.com/article.php/peggy "Peggy," A Light Emitting Pegboard Display]
 +
* Christmas trees are now led based so: [http://computerchristmas.com/ The #1 Site for Controlling Christmas Lights with a Computer]
 +
* [http://members.misty.com/don//ledx.html Don Klipstein's LED Main Page]  Lots of good info.
 +
* [http://www.instructables.com/id/Synchronizing-Fireflies/ Synchronizing Fireflies] ATtiny super smart swarm of LEDs.
 +
* [http://www.u-disp.com/ U-Disp - An Open Sourced USB display]
 +
* [http://crushingabyss.com/sunrise_alarmclock/index.html Sunrise LED Alarm Clock] ATMega8515 controlling two color-mixed high-power LED channels with PWM.  Also contains a RTC circuit and a serial port.  Full source including PC Windows serial port communication code.
 +
* [http://dotmatrixdesign.tumblr.com/ dotmatrixdesign: Twitter LED Scroller Build Log]: an Arduino shield for a 7x5 LED matrix, and all the schematics, board layouts, Arduino firmware, and PC software to make it scroll text from a Twitter feed.
 +
* [http://www.thekeeser.com/Projects/mechanically_scanned_led_display.htm "Mechanically Scanned LED display"] by Chris "thekeeser". Using PIC16F628, a infrared 1 pulse per revolution sensor so it can automatically adapt to any rotation rate, and multi-colored LEDs. Detailed notes on the software development.
 +
* [http://sites.google.com/site/libby8dev/stripes/examples "PhorsePOV - a minimal handheld POV"] by Julian Skidmore. Avr AtTiny25 based driving 6 LEDs and uses a single button to enter text.
 +
* [http://electronics.stackexchange.com/questions/tagged/pov Electronics Stackexchange: questions tagged POV Persistence Of Vision] has a long list of questions people are asking about POV displays, many of them with excellent answers.
 +
* [http://ohmprojects.com/prop/prop.html Ohm's propeller display] and [http://ohmprojects.com/prop-rgb/prop-rgb.html Ohm's RGB propeller display]
 +
 +
* ahmedebeed555. [http://www.instructables.com/id/7-segment-pov-16F84/ "7 segment pov 16F84"].
 +
 +
It might be nice to make a [[spinning electronic]]s page to describe the many weird and wonderful ways that people (a) get power to the spinning electronics, and (b) transmit data to and from the spinning electronics.
 +
POV displays are the most popular kind of spinning electronics,
 +
but the same approaches are useful for other kinds of spinning electronics
 +
such as run-time tire pressure sensors and [http://electronics.stackexchange.com/questions/12704/electrified-vertical-mounted-rotary-joint-questions bioreactors].
 +
 +
[[category:projects]]

Latest revision as of 17:40, 19 November 2014

POV display[edit]

A "persistence of vision display" (POV display) has only a single line of LEDs blinking on and off. The display mechanically sweeps it across a person's field of view, giving the illusion of a 2D display.

(Do I need a diagram or a picture here?)

(Nearly all LED displays in microwave ovens and alarm clocks electrically sweep the digits across a person's field of view, giving the illusion that it's displaying all 4 digits of the time "12:55" when actually only one digit is illuminated at any one instant).

User:DavidCary is building yet another "POV display".

I plan on putting a few features into my display that I haven't seen in any other so far:

  • bright blue LEDs (even though blue is usually the most expensive color ... although sometimes "true green" is even more expensive than blue).
  • no slip rings -- just pumping energy across an air gap
  • ... and a few other features that I'm keeping hush-hush.

I want lots of lumens. Unfortunately, when I go to pick LEDs out of the catalogs, they're not rated in lumens, they're rated in candelas.


Is it even possible to estimate "lumens" from the catalog information?

You can use this table to get an approximate conversion from candelas to lumens. Find your LED beam width in degrees, and divide the candelas number in your specs by the cd/lm factor listed for that beam angle to get lumens.
beam angle cd/lm
beam angle = 5 divide candela value by 167.22
beam angle = 10 divide candela value by 41.82
beam angle = 15 divide candela value by 18.60
beam angle = 20 divide candela value by 10.48
beam angle = 25 divide candela value by 6.71
beam angle = 30 divide candela value by 4.67
beam angle = 35 divide candela value by 3.44
beam angle = 40 divide candela value by 2.64
beam angle = 45 divide candela value by 2.09

Hope this helps.....Dr. Andrew Thomas...

Do you know what the difference is? Does your flashlight really produce 10 times the light ( in lumens)? Or does the flashlight merely focus its light on a tiny spot, so that that spot gets 10 times as many candelas ?

For example, check out these 2 LEDs: $8.75 SSP-LX6144C7UC : 4000 mcd at 120 mA $8.75 SSP-LX6144D7UC : 1800 mcd at 120 mA

From the mcd rating, it appears that the first one is more than 2wice as bright -- and it is, if you're directly in front of it when you look at it. However, if you're even the tiniest bit off-center, the second one is much brighter -- in fact, the total lumens that second LED puts out (2500 mlm) is slightly more than the total lumens than the first one. If you diffuse the light and try to light up a whole room with an array of them, the second one will make the room brighter.

I'm currently planning on using these in my first POV display:

  • $1.32 Telux TLWB7900 : blue : 330 mlm, 231 mcd at 50 mA. (price in ones from http://Newark.com/ )

Other LEDs I considered using in my POV display (and may re-consider for my next one):

  • $18.89 "Lamina light engine" BL-22B1-0140 : 22000 mlm at 420 mA. (this price includes the required heat sink -- price in ones from http://Digikey.com/ ). This has the most lumens per dollar I've found so far (for blue LEDs).
  • $8.750 Sunbrite LuxLEDs SSP-LX6144D7UC blue: 120 mA, 2500 mlm, 1800 mcd (Odd that the red Sunbrite LuxLEDs are cheaper at Newark, the other colors cheaper at Digikey.) cheapest $/lumen blue LED, except for the "light engine"
  • $2.550 Lumex "DSP LED" 67-1876-ND: blue, 5 mm, 2500 mcd ( DigiKey ) apparently have some kind of internal chip. All colors run at 2.0 V nominal (1.5 V minimum) (rather than running on current like most LEDs. unfortunately, the data sheet doesn't suggest how much current they take -- I presume more than 20 mA).
  • $1.600 Sunbrite "based LED" SSP-01TWB7UWB12 (441-1007-ND) blue 10 mm 20 mA 7000 mcd
  • $5.980 GM5WA06270A SMT RGB (35 mA red, 35 mA green, 35 mA blue) 3000 mcd (full color range -- apparently used for digital camera flash ?) (Digikey)
  • Mouser: hi-power LEDs ( http://www.mouser.com/search/refine.aspx?Ntt=LEDs+hi-power ) shows "lumens" directly -- exactly what I wanted.

further reading[edit]

Many POV devices are based on the PIC, see the PIC Links and search on POV.
Spoke-POV and propeller clocks links:

While most POV displays spin the LEDs in a complete circle, some "wiggle" the LEDs back and forth:


Is this http://led-display-and-design-swicki.eurekster.com/ relevant?

I think so--71.234.233.163 18:06, 22 June 2007 (PDT)


  • "the Orbital Rendersphere"[4][5][6][7][8], aka the "Big Giant Spinning Limb Slicer".

The Orbital Rendersphere displays images and videos on a four-foot diameter spherical surface using persistence of vision (POV). Uses a (stationary) Mac Mini to render each frame, and a (spinning) BeagleBone Black to update the LEDs. Slip ring for power; Wi-Fi to transfer data. The Orbital Rendersphere displays video at 30 frames per second by spinning four vertical LED strips spaced 90 degrees apart at 450 RPM. 36 feet of WS80211 LED strips. (But it looks like 2 complete circles, each 4 ft diameter -- isn't that closer to 25 feet?) 102x224 pixel resolution. Several people comment that this is the biggest POV globe they've ever seen. It's mentioned on p. 1-44 of John Baichtal, "Robot Builder"[9]. Uses LEDscape[10].

  • Mike Szczys. "Full-color video on a spinning POV display". Built by Félix, Sylvain, and Jérémy at at Telecom ParisTech. highest-resolution POV display I've seen so far. "The time it took us was roughly two months full time". (Does this have a name?)
  • "Borg Ventilator". Twice the resolution of the Telecom ParisTech display? A total of 244 RGB LEDs (spread over 4 wings). Has standard VGA input; a Xilinx FPGA and a bunch of support chips convert to circular coordinates. Power through slip rings. Data through non-contact inductive transfer (recycled VCR head). "The speed is infinitely adjustable between 0 and 2500 rpm / min. The FPGA adapts to the actual speed"
  • Collin Cunningham. "Ceiling fan POV display"[13][14]. A single ATMEGA328 and 20 74HC595 shift registers to drive the LEDs. 32 LEDs per fan blade x 5 blades = 160 LEDs.
  • Gareth Branwyn. "MonkeyLectric 3D spherical POV display"[15][16]. by Dan Goldwater / MonkeyLectric.

Mentions "we recently decided to move this project to the Raspberry Pi board away from Arduino. The capabilities and processing power of the Pi are much greater than Arduino. ... [but] ... the refresh rate is too slow, much slower then the Arduino was. We need some help figuring out how to turn up the SPI speed with our current software arrangement. ... used Phillip Burgess' at Adafruit 'Light Painting' Python script to process images and output to the LPD8806 http://learn.adafruit.com/light-painting-with-raspberry-pi/software "

  • PixelPi: RGB Pixel Array Driver for the Raspberry Pi[17]. Based on Phillip Burgess 'Light Painting' Python script. Apparently supports many different POV hardware displays.

(FIXME: make a separate section for bicycle POV displays)

  • Hazard. "RGBike POV - Open project". Arduino compatible; 16 RGB LEDs; hall effect sensor; through-hole components and single-layer PCB for easy fabrication.

It might be nice to make a spinning electronics page to describe the many weird and wonderful ways that people (a) get power to the spinning electronics, and (b) transmit data to and from the spinning electronics. POV displays are the most popular kind of spinning electronics, but the same approaches are useful for other kinds of spinning electronics such as run-time tire pressure sensors and bioreactors.