Post by thread:[EE] RGB LEDs. (was planetarium prop-clock)

On 9/5/05, Jason <spam_OUTpicTakeThisOuTcanadaspeaks.com> wrote: {Quote hidden}> From: "Robert Rolf" <.....Robert.RolfKILLspam@spam@ualberta.ca> > Sent: Sunday, September 04, 2005 6:33 PM > > > Or 4 strips, at 90 degrees, to get better resolution yet. > > Use the smallest LED's you can get with adequate brightness. > > White or yellow to look more like stars. RGB LEDS would be cool but > > much more costly. > > I've been toying with the idea of building something similar with RGB LEDs. > I'd have around 16 of them 1" apart along one end of a meter stick. The > system would build pictures that are visible as the meter stick is swung. > > Where I ran into problems was controlling the LEDs. 16 RGB LEDs is 48 LEDs > to control, and to get full colour, I 'd need to PWM them individually I > couldn't come up with a good way to drive them. I know there are LED driver > chips that can do it, but they're only in tiny surface mount packages with > lots of pins for all those LED, so they look like too much work to use for > what I'll get out of the project. > > This is a bit off the thread's topic, but what interesting things have > people done with RGB LEDs? I've seen things like OGGz, the Flexiglow > mousepad, etc that just light things up with cycling colours. I'm looking > for something more novel. > > Jason > While we're on the subject, where is a good source for RGB LEDS? Regards, Mark markrages@gmail -- You think that it is a secret, but it never has been one. - fortune cookie

Mark Rages wrote: > While we're on the subject, where is a good source for RGB LEDS? > > Regards, > Mark > markrages@gmail I got mine here: http://www.lsdiodes.com/shop/index.php?main_page=product_info&cPath=5&products_id=62 A buck-ten each. R:3000 mcd typical (20ma) G:5500 " " B:5500 " " These are common cathode; common anodes are available if you search enough. The Chinese distributor mentioned a few months ago is much cheaper *if* you buy a lot. And they had both common-anode and common-cathode, if I remember. YMMV

From: "Marcel Duchamp" <marcel.duchampKILLspamsbcglobal.net> Sent: Monday, September 05, 2005 4:46 PM > The Chinese distributor mentioned a few months ago is much cheaper *if* > you buy a lot. And they had both common-anode and common-cathode, if I > remember. I don't know if this is the Chinese distributor you're referring to but I buy my LEDs from the "Chi Wing LED product shop" on ebay. They charge $39 for 50 RGB LEDs (it doesn't say if it's common-anode or cathode, but iirc the ones I have from them are common-anode).

If you are doing imaging, you won't want to use the clear ones. They project 3 color spots. The diffused ones mix the color very well. - Ben On 9/5/05, Jason <.....picKILLspam.....canadaspeaks.com> wrote: {Quote hidden}> From: "Marcel Duchamp" <EraseMEmarcel.duchampspam_OUTTakeThisOuTsbcglobal.net> > Sent: Monday, September 05, 2005 4:46 PM > > > The Chinese distributor mentioned a few months ago is much cheaper *if* > > you buy a lot. And they had both common-anode and common-cathode, if I > > remember. > > I don't know if this is the Chinese distributor you're referring to but I > buy my LEDs from the "Chi Wing LED product shop" on ebay. > > They charge $39 for 50 RGB LEDs (it doesn't say if it's common-anode or > cathode, but iirc the ones I have from them are common-anode). > > > -