On Friday, August 10, 2012 11:34:58 PM UTC+2, Daniel Pitts wrote:> > I got my TL5916 for 88 cents, and the 74HC238 for 25 cents. Where the > MAX7219 is over $10 from the same supplier ($13 if I wanted DIPS, which > I do for now). >On eBay they go for $0.99 with shipping included... http://www.ebay.com/itm/280849405928 Or ... two of them for $1.75: http://www.ebay.com/itm/300739928063 The only thing I didn't figure out yet is scalability. The MAX7219 is perfect for a 4x4x4 cube. Two of them can do a 5x5x5 cube but do I need eight of them for an 8x8x8...? Can I add a multiplexer and do it with just one chip? It might work, I dunno. The multiplexer runs at 800Hz. Is it enough...? The TL5916 *might* be more scalable because you have total control over all the timing. I'm just reading all the datasheets now, thinking it might be a good time to get started on my own LED cube. :-)
How to power my circuit.
Started by ●August 7, 2012
Reply by ●August 10, 20122012-08-10
Reply by ●August 11, 20122012-08-11
On Saturday, August 11, 2012 1:05:57 AM UTC+2, fungus wrote:> > The only thing I didn't figure out yet is > scalability. The MAX7219 is perfect for a > 4x4x4 cube. Two of them can do a 5x5x5 cube > ...I found a big flaw in my thinking: Although two MAX7219s can light up 128 LEDs, they have be connected in 8x8 matrices. Physically wiring up a 5x5x5 cube using two chips isn't going to work out. You could theoretically do it with three chips but it's messy, you can't build it in five neat slices then stack them up. Saving a couple of bucks to use three chips instead of five doesn't seem worth it for a hobby project. 4x4x4 can be done neatly with one chip but after that you're really looking at one chip per layer. PS: Odd-numbered cubes seem to be much more interesting/pretty then even-numbered cubes. 5x5x5 and 7x7x7 are good sizes. 7x7x7 is better than 8x8x8.
Reply by ●August 12, 20122012-08-12
On Saturday, August 11, 2012 1:05:57 AM UTC+2, fungus wrote:> > thinking it might be a good time to get > started on my own LED cube. :-)I gave in to temptation, ten MAX7219s for $5.10 http://www.ebay.com/itm/300739928460 Now I just need a load of LEDs and my cube will be under way... I think I'll go for 5x5x5 - 7x7x7 is three times as many LEDs, that's a lot more work/expense than 5x5x5.
Reply by ●August 12, 20122012-08-12
On Sun, 12 Aug 2012 03:52:01 -0700 (PDT), fungus <tooby@artlum.com> wrote:>On Saturday, August 11, 2012 1:05:57 AM UTC+2, fungus wrote: >>=20 >> thinking it might be a good time to get >> started on my own LED cube. :-) > >I gave in to temptation, ten MAX7219s for $5.10 > >http://www.ebay.com/itm/300739928460 > >Now I just need a load of LEDs and my >cube will be under way... > >I think I'll go for 5x5x5 - 7x7x7 is >three times as many LEDs, that's a lot >more work/expense than 5x5x5.I've got some very nice, 16x16 RGB arrays. Each already has 6 ICs for driving all that. Separate supplies for each color, turn-pot resistors for adjusting white balance by setting the 100% current source levels, and pwm capability within that range from 0/256 to 255/256 of the 100% current level for each color of each RGB LED. Used mostly to make outdoor TV sets, driven by NTSC or some other TV broadcast code. These bricks have huge heat sinks behind each one to dissipate the power. Be aware of the potentials for that aspect when you start talking about hundreds of LEDs. Jon
Reply by ●August 12, 20122012-08-12
On Saturday, August 11, 2012 12:47:45 AM UTC+2, k...@att.bizzzzzzzzzzzz wrote:> > >Says who? Not all LED applications are "can > >you see the LED?" > > You don't want to see the LED? Read the fucking > thread before you make more of an ass of yourself.You might not want to see the LED directly, no. You might just want the light from it. I'm sure you can think of an example if you really try.> >I can use that to one with 2xAA batteries. > >It uses PWM switching to do its job, I bet > >it's more efficient for lighting an LED than > >3xAA plus a current source that's guaranteed > >to eat 0.6V. > > If you're going to all that trouble, > just use a damned wall wart and be done > with it.How is that any 'trouble'? Methinks you're trying to steer attention away from your untenable position.
Reply by ●August 12, 20122012-08-12
On Sunday, August 12, 2012 11:42:40 PM UTC+2, Jon Kirwan wrote:> > These bricks have huge heat sinks behind each one to > dissipate the power. Be aware of the potentials for that > aspect when you start talking about hundreds of LEDs. >They're packed together quite tightly. In a cube the LEDs have more air around them. How are they multiplexed? What current do the LEDs run at? I imagine they drive them quite hard for daylight viewing.
Reply by ●August 12, 20122012-08-12
On Sun, 12 Aug 2012 17:30:03 -0700 (PDT), fungus <tooby@artlum.com> wrote:>On Saturday, August 11, 2012 12:47:45 AM UTC+2, k...@att.bizzzzzzzzzzzz wrote: >> >> >Says who? Not all LED applications are "can >> >you see the LED?" >> >> You don't want to see the LED? Read the fucking >> thread before you make more of an ass of yourself. > >You might not want to see the LED directly, no. >You might just want the light from it.READ THE THREAD, MORON.>I'm sure you can think of an example if >you really try.I bet you could understand a simple thread if you really worked at it.>> >I can use that to one with 2xAA batteries. >> >It uses PWM switching to do its job, I bet >> >it's more efficient for lighting an LED than >> >3xAA plus a current source that's guaranteed >> >to eat 0.6V. >> >> If you're going to all that trouble, >> just use a damned wall wart and be done >> with it. > >How is that any 'trouble'?Idiot.>Methinks you're trying to steer attention >away from your untenable position.Look in the fucking mirror, moron.
Reply by ●August 13, 20122012-08-13
On Sun, 12 Aug 2012 18:10:24 -0700 (PDT), fungus <tooby@artlum.com> wrote:>On Sunday, August 12, 2012 11:42:40 PM UTC+2, Jon Kirwan wrote: >>=20 >> These bricks have huge heat sinks behind each one to >> dissipate the power. Be aware of the potentials for that >> aspect when you start talking about hundreds of LEDs. > >They're packed together quite tightly. In a cube >the LEDs have more air around them.Well, their separation is 5mm and 3mm, depending on module.>How are they multiplexed?There are six driver ICs. The 16x16 is divided into two 8x16 halves. Each half has 3 driver ICs, one for each color. Each with different source supplies. (Blue needs higher voltage than red, for example, and at these dissipations you do NOT want the same rail for all three colors.)>What current do the LEDs run at? I imagine they drive them >quite hard for daylight viewing.I'd have to check my notes. But I remember that they roughly dissipate about 80W per. Jon
Reply by ●August 13, 20122012-08-13
On Monday, August 13, 2012 4:06:52 AM UTC+2, k...@att.bizzzzzzzzzzzz wrote:> > >> >I can use that to one with 2xAA batteries. > >> >It uses PWM switching to do its job, I bet > >> >it's more efficient for lighting an LED than > >> >3xAA plus a current source that's guaranteed > >> >to eat 0.6V. > >> > > >> If you're going to all that trouble, > >> just use a damned wall wart and be done > >> with it. > > >How is that any 'trouble'? > > Idiot. >Seriously though, how is using a 3.3V booster more trouble than using a 5V booster? Both are a *lot* less trouble than adding a current sink to every single LED. I'd like to know. As for efficiency...I'm game. Ill put a 3.3V booster board up against a current source, let's see whose battery lasts longer.
Reply by ●August 13, 20122012-08-13
