POV display

From OpenCircuits
Revision as of 03:37, 5 February 2008 by (Talk)

Jump to: navigation, search

office des migrations internationales montreal jesses girl low mortgage quote rate spencers tv blood cuffs fork pressure tuning certified loose diamonds ecosphere associates jackie chan on bruce lee limoncello pallini i-pod mini military dependant scholarship prevent snoring women steel toe shoes i lil lyric sho will wyte forum galant vr4 anime funny naruto video overball navy advancement atv racing equipment av vcs 3.1 diamond key anticrepuscular rays bridal hair accessory sophie blake jrs movie 2005 calendar coco ice t z-tel brace 4x4 part new orleans photo muscular system rue rivoli paris kitchen label retro amature wrestling movies empire game star video war war weight watcher zero point food alphabetical index extreme surfing videos arcade download game video sohbet siteleri class h power amps melanie sykes page michigan wrestling rankings aebn movie erroneous enlistment adult santa suit one call away address stamp emo kid song video houston police department jobs computer based training amp connector ymmss penny arcade bristow nissan pavilion va wildfire oak brook cool trick zippo oc ottawa transpo family crests and shields pinnicles national park lever problem apartment houston tx website norton anti virus 2005 serial sonburn inc exorcism emily rose movie home montana elk hunting kfc gravy recipe courtroom pics screen capture swing kids movie pictures portfolio management free rap beat sample bridget the midget terri runnels nude picture station house cafe melanda park vision atv rims are we there yet movie rating christianity magazine today today amateur home spy video edit movie clips gunflint trail mn christian motorcycle association jeep girl femenique thick hairy pussy url joe brand store father daughter ashlee simpson booed orange bowl video miramar brig izo movie big bitch fat kyles mom park south boston video production lil bow wow picture answer my question.com fireplace door expert guitar hero video kalisto dreamcast installing instructions replacement window amor no si tu video vuelve croche e trico unkinglike euronext.com computer hacking katrina new orleans video roadrunner cincinnati ohio custom vehicle graphics audio equipment recording supply video kurosaki ichigo wallpapers salak salak salak salak si sinan sinan sinan sinan veronica mars picture 1996 bmw 318 legal help for dwi anime berserk hardcore sex clubs house decor princess cut diamond earring applied foundation mesothelioma research baby float swivel barstools mig supply welding cheri oteri vinyl siding installation magnetic marketing custom sport bikes attacking reporter snake video saturday night live band february 5 2005 kanta laga video vanadium steel all-inclusive resorts ying yang twins - wait emotions john reuben kayne west work out plan video act exemptions freedom information gorillaz art stevens untitled rock show diving picture sky aerosmith video crazy grass remover stain 2007 convention cub schedule adult fitness older video b j tarsier lathe mini sale luke picket mother jones == POV display ==

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?

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

Spoke-POV and propeller clocks links:

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

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

Personal tools