How to power my circuit.

[fungus]

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.

 

[fungus]

On Monday, August 13, 2012 10:22:41 AM UTC+2, Jon Kirwan wrote:

I'd have to check my notes. But I remember that they roughly
dissipate about 80W per.

So a dozen panels is a kilowatt. A big
display is more like 20kW... 180Amps?*
Get a big thick cable.

*(at 110VAC)

 

[Uwe Hercksen]

Daniel Pitts schrieb:

So to power 192 LEDs (8x8xRGB) I could spend spend over $30 using
MAX7219, or I could spend just 3*.88+.25=$2.89. I think a 90% cheaper
solution is the better solution, especially for a hobby project.

Hello.

if you want to power 192 LEDs with a mean current of 10 mA, you will
need 1.92 A only for the LEDs if all are on. That is too much for three
AA cells in series. Use a wall wart as recommended by the other posters.

Bye

 

[fungus]

On Monday, August 13, 2012 5:43:52 PM UTC+2, Uwe Hercksen wrote:

if you want to power 192 LEDs with a mean current of 10 mA, you will
need 1.92 A only for the LEDs if all are on. That is too much for three
AA cells in series. Use a wall wart as recommended by the other posters.

They will never all be on at the same time,
only a single column of 8 LEDs. The maximum
power is only 80mA.

 

[Daniel Pitts]

On 8/12/12 3:52 AM, fungus wrote:

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.

If you want to get cheap LEDs, search for a batch of 1000 on ebay. I've

gotten them around 1˘ an LED for reds/yellows/greens. and 2˘ to 3˘ for
teal/uv (I was trying to get blue, but teal was what I got. My bad for
not looking at the wavelength)

Note, 1000 is not quite enough for a 32x32 display. It is plenty for a
single 8x8x8 cube, with enough left over to also make a 7x7x7. You can
make 8 5x5x5 with 1000 leds.

 

[fungus]

On Tuesday, August 14, 2012 8:30:43 PM UTC+2, Daniel Pitts wrote:

I think I'll go for 5x5x5 - 7x7x7 is

three times as many LEDs, that's a lot

more work/expense than 5x5x5.



If you want to get cheap LEDs, search for a batch of 1000 on ebay. I've

gotten them around 1ďż˝ an LED for reds/yellows/greens. and 2ďż˝ to 3ďż˝ for

teal/uv (I was trying to get blue, but teal was what I got. My bad for

not looking at the wavelength)

Yep, I did that. There's 500 3mm diffuse blue
LEDs on the way.

I still didn't decide between 5x5x5 and 7x7x7.
It's a lot more LEDs but the wiring/programming
isn't really more difficult. Might have to forget
about USB power, too.

OTOH my girlfriend likes soldering...every time
I get the soldering iron out she's like, "Oh,
let me do it..."

 

[Daniel Pitts]

On 8/15/12 4:31 AM, fungus wrote:

On Tuesday, August 14, 2012 8:30:43 PM UTC+2, Daniel Pitts wrote:


I think I'll go for 5x5x5 - 7x7x7 is

three times as many LEDs, that's a lot

more work/expense than 5x5x5.



If you want to get cheap LEDs, search for a batch of 1000 on ebay. I've

gotten them around 1ďż˝ an LED for reds/yellows/greens. and 2ďż˝ to 3ďż˝ for

teal/uv (I was trying to get blue, but teal was what I got. My bad for

not looking at the wavelength)


Yep, I did that. There's 500 3mm diffuse blue
LEDs on the way.

I still didn't decide between 5x5x5 and 7x7x7.
It's a lot more LEDs but the wiring/programming
isn't really more difficult. Might have to forget
about USB power, too.
Well, if you have good multiplexing and don't need to run at a high

duty-cycle, USB might provide enough power.

OTOH my girlfriend likes soldering...every time
I get the soldering iron out she's like, "Oh,
let me do it..."
Lucky you. I wasn't able to even start on electronics projects until I

was single. ;-)

Although, it was for other reasons.

 

[Daniel Pitts]

On 8/7/12 5:39 PM, Daniel Pitts wrote:

Hello,

So far, all of my circuits have had the power supplied by an Arduino
(compatible) board. I'm going to try to change the setup here a little,
and design a circuit that has just an ATTiny in its place, but now I
have to think about power supply.

The circuit I'm envisioning is going to have three Texas Instruments
"TLC5916" constant-current sink's, powering one column of a multiplexed
8x8 RGB led matrix. The circuit will also have an ATTiny85 (or ATTiny84,
depending on a few things), and a 74HC238 (to select the row on the LED
matrix).

Now, if I'm reading the specs right, I think I can power the whole thing
on 3 AA batteries (4.5 volts). But if I wanted to have more robust power
handling, I'm not sure what I want to do. I'd like to try to keep the
circuit cheap, and potentially have it powered by a wall socket or USB.
I also don't have the time/money to etch my own PCB, so something that I
can plug into my protoboard is preferable.

Is it just me, or is deciding on a power supply a relatively difficult
problem, compared to other aspects of working on digital circuitry?

Thanks in advance for any suggestions!

--
Daniel.

Thanks to everyone who gave advice.

For prototyping purposes, I ended up buying a 5v linear voltage
regulator from Radio Shack. It lets me power my project from a 9v
battery. I don't know how the performance is, whether it's sufficient
for a wearable or always-on. If I wanted a non-wearable always-on, I
can get a wall adapter.

 

[fungus]

On Thursday, August 16, 2012 5:42:17 PM UTC+2, Daniel Pitts wrote:

I still didn't decide between 5x5x5 and 7x7x7.
It's a lot more LEDs but the wiring/programming
isn't really more difficult. Might have to forget
about USB power...

Well, if you have good multiplexing and don't need to run at a high

duty-cycle, USB might provide enough power.

With one MAX7219 chip per layer I could have
49 LEDs on at the same time. They can control
the brightness with PWM so I guess I could
have a switch on the box for "USB mode" to
lower the power a bit. Maybe I can also have
an indoor/outdoor setting as well - run the
LEDs at higher power.

I should probably build in some sort of
safety features if I do that though. USB
doesn't have over-current protection AFAIK.

First I have to see how bright the LEDs are
in real life.

 

[Jasen Betts]

On 2012-08-16, Daniel Pitts <newsgroup.nospam@virtualinfinity.net> wrote:

So far, all of my circuits have had the power supplied by an Arduino
(compatible) board. I'm going to try to change the setup here a little,
and design a circuit that has just an ATTiny in its place, but now I
have to think about power supply.

The circuit I'm envisioning is going to have three Texas Instruments
"TLC5916" constant-current sink's, powering one column of a multiplexed
8x8 RGB led matrix. The circuit will also have an ATTiny85 (or ATTiny84,
depending on a few things), and a 74HC238 (to select the row on the LED
matrix).

Now, if I'm reading the specs right, I think I can power the whole thing
on 3 AA batteries (4.5 volts). But if I wanted to have more robust power
handling, I'm not sure what I want to do. I'd like to try to keep the
circuit cheap, and potentially have it powered by a wall socket or USB.
I also don't have the time/money to etch my own PCB, so something that I
can plug into my protoboard is preferable.

Is it just me, or is deciding on a power supply a relatively difficult
problem, compared to other aspects of working on digital circuitry?

Thanks in advance for any suggestions!

--
Daniel.


Thanks to everyone who gave advice.

For prototyping purposes, I ended up buying a 5v linear voltage
regulator from Radio Shack. It lets me power my project from a 9v
battery. I don't know how the performance is, whether it's sufficient
for a wearable or always-on. If I wanted a non-wearable always-on, I
can get a wall adapter.

Those 9V batteires are one of the most expensive ways to buy electricity,
and the regulator is throwing almost half the energy away.

4 rechargable AA Nimh cells get you the voltage you need and will run
for 5 times longer between charges. 4xAAA cells will cost about the
same as AA but be about as heavy as the 9V and still outlast it by a
factor of 2

--
⚂⚃ 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---

 

[Daniel Pitts]

On 8/17/12 4:20 PM, Jasen Betts wrote:

On 2012-08-16, Daniel Pitts <newsgroup.nospam@virtualinfinity.net> wrote:
For prototyping purposes, I ended up buying a 5v linear voltage
regulator from Radio Shack. It lets me power my project from a 9v
battery. I don't know how the performance is, whether it's sufficient
for a wearable or always-on. If I wanted a non-wearable always-on, I
can get a wall adapter.

Those 9V batteires are one of the most expensive ways to buy electricity,
and the regulator is throwing almost half the energy away.

4 rechargable AA Nimh cells get you the voltage you need and will run
for 5 times longer between charges. 4xAAA cells will cost about the
same as AA but be about as heavy as the 9V and still outlast it by a
factor of 2

Thanks for the tip.

The regulator I bought (from radio shack, just to get started on
something) has a rated minimum voltage of 7v, which is just above 4xAA.
However, I don't know that my project needs a full 5v. I actually have
a 4xAA pack, so I could try it and see if it powers my project sufficiently.

If I ever "mass produce" this project (meaning make more than 1), I'll
try to find a more efficient power system.


Thanks,
Daniel.