RGB controller

[(*steve*)]

In your response, you added the word "just" which clarifies what you mean.

Perhaps you need to read what I wrote and not what you quoted.

In any case this is pointless because it's not helping solidshark.

 

[solidshark91493]

Well.. Im about to give up on this, I didnt know wiring 6 led's to a controller was the hardest thing on earth. .-.
I still dont know what to do.

 

[(*steve*)]

Heres the spec sheet for my led's
http://i1248.photobucket.com/albums/hh496/solidshark91493/Untitled-1.png

That says 20ma
So I have to limit the lights to the individual voltage levels correct? .-. so Ill need 18 resistors,

And ok, so 7.5 amp wall wart. does amp equal watt? Im sure I could look it up but Ill ask anyway. They sell a 6 watt one, and a 15 watt one. (Smallest ones) Maybe I could get a different one somewhere else that would be better?

It would be better to ask this in the thread. Also you need to tell me how many LEDs you are planning on using.

The short answer is that a 12V 7.5A power supply is a 90W power supply (watts are volts x amps)

a 90 watt supply? thats WAY too much. I can power 6 rgb leds with my arduino off a 9 volt battery.. :|
I cant imagine I would need more than 15 watt.. But I guess I could still be wrong.

Im using 6 of these.
http://www.ebay.com/itm/100pcs-x-5m...Common-Anode-LED-Red-Green-Blue-/261083069774
I have 600 of them. But I only wanted to use 6 since what im putting them in isnt that large. I could go to 9 I suppose.

You have 6 leds. At 20mA max for each R, G, and B, that's 0.06A * 6 = 0.36A.

From a 12V power supply that's 0.36 * 12 = 4.3W.

Tiny 12V power supplies are a dime a dozen. You'll probably find a 12V 1A power supply very easily.

Connect them up as you suggested:

Do you know how to calculate the resistor values?

And please don't send me private messages for things like this, ask them in the thread.

 

[solidshark91493]

You have 6 leds. At 20mA max for each R, G, and B, that's 0.06A * 6 = 0.36A.

From a 12V power supply that's 0.36 * 12 = 4.3W.

Tiny 12V power supplies are a dime a dozen. You'll probably find a 12V 1A power supply very easily.

Connect them up as you suggested:

Do you know how to calculate the resistor values?

And please don't send me private messages for things like this, ask them in the thread.

I only did that to try and get an answer further. ok then.

12v 1A power supply. Got it.
resistor values? No idea, I had a calculator but Idk where it was from.

 

[(*steve*)]

I only did that to try and get an answer further. ok then.

However, you were correct

12v 1A power supply. Got it.

Yep, anything from 360mA up to whatever. 1A will allow you to expand to 16 LEDs if you need to.

resistor values? No idea, I had a calculator but Idk where it was from.

Easy The theory stuff is here:https://www.electronicspoint.com/got-question-driving-leds-t256849.html

I'll do one, and you can do the other two.

First refer to this (as supplied by the person you bought the LEDs from):

The rule is R = (Vs - Vf) / If

So for the red LED at 20mA,

R = (Vs - Vf) / If
= (12 - 2.4) / 0.020 [I used the typical value. The min value would be more conservative.]
= 9.6 / 0.02
= 480 ohms.

The nearest commonly available size resistor greater than this is 560 ohms, but the one just below (470 ohms) is close enough to use.

See here for standard value resistors (look at the E12 series and remember you can multiply these by any power of 10 (1, 10, 100, 0.1, 0.01, etc)

 

[solidshark91493]

Got this.
http://www.ebay.com/itm/12V-1A-Powe...arts_and_Accessories&var=&hash=item53fc977a54

Google'd another calculator,And got a 430 ohm resistor for 3.4v at 20 ma which is the max for green and blue.
correct?

 

[(*steve*)]

Yep, that's right.

I'd probably use 470 ohm resistors for all three. That way there's less chance of making an error.

My advice is to wire us a single LED to the controller first. This will ensure you have everything wired up right. If you make a mistake you'll only destroy 1 LED

 

[solidshark91493]

Yep, that's right.

I'd probably use 470 ohm resistors for all three. That way there's less chance of making an error.

My advice is to wire us a single LED to the controller first. This will ensure you have everything wired up right. If you make a mistake you'll only destroy 1 LED

Ok. Ill give it a try. and report back, it'll be a few days though.

 

[solidshark91493]

I apologize for the double post.
But, My controller is here, and my pack of 100 470ohm resistors arrived. It works perfectly. Only thing I havent gotten is the power supply. Im running the controller from my arduino. 5v and ground and it works fine. so Im kinda puzzled why it says its 12v.. .-.
But the lights dont get hot now with the resistors. and the resistors are cold too. Before I got the resistors if I put it on 5v the lights would start getting real hot. But at 3v they were ok.
Ive got two lights on and they look the same brightness, And they look plenty bright enough.

 

[(*steve*)]

That's excellent news.

If that really is a 5V power supply (have you measured it) then the LEDs are going to be running at a lower current. If they're bright enough that's fine.

It is possible that the power supply is 12V as the arduino has a voltage regulator which steps the voltage down to 5V, although running them at 12V is typically a little higher than typical -- 9V is more common. And of course, you can run them from 5V.

 

[solidshark91493]

That's excellent news.

If that really is a 5V power supply (have you measured it) then the LEDs are going to be running at a lower current. If they're bright enough that's fine.

It is possible that the power supply is 12V as the arduino has a voltage regulator which steps the voltage down to 5V, although running them at 12V is typically a little higher than typical -- 9V is more common. And of course, you can run them from 5V.

Well it was just to test it and make sure it works. Im not quite sure when the power gets here. Hopefully with the load of 6 lights it will keep the resistors from getting hot.

Since im wiring them together should I use heat shrink OVER the resistor? or would that prevent it from being able to be cooled by air or something..

 

[(*steve*)]

Because there's a resistor for each LED element, they will not get hotter as you add LEDs. Your power supply might though.. (but that was the point of making sure the power supply was of a suitable capacity.

In this application I can see no reason not to heatshrink the resistors. It may help prevent shorts, and it depends on how you're wiring them as to whether this is likely or not.

Yes, the heatshrink will reduce the cooling to the resistors, but in this case they require so little it should be fine. (at 20mA they would dissipate 0.2W, and as long as these are 1/2W resistors or greater, heatshrinking will be fine)

 

[solidshark91493]

Because there's a resistor for each LED element, they will not get hotter as you add LEDs. Your power supply might though.. (but that was the point of making sure the power supply was of a suitable capacity.

In this application I can see no reason not to heatshrink the resistors. It may help prevent shorts, and it depends on how you're wiring them as to whether this is likely or not.

Yes, the heatshrink will reduce the cooling to the resistors, but in this case they require so little it should be fine. (at 20mA they would dissipate 0.2W, and as long as these are 1/2W resistors or greater, heatshrinking will be fine)

1/4th 470 ohm. :|
Im going to place the led's in wood, and have the wires hidden inside the stand. encapsulated. Wires will be soldered onto the led pins, then to the resistors, then to the controller.

 

[(*steve*)]

1/4 w is pushing it for covering in heatshrink. However it does depend on whether the LEDs will be a t full brightness and for how long. If your controller uses PWM and keeps the average brightness low, it may not be too much of an issue. Also the leads of the resistor will provide some heatsinking.

If they remain cool to the touch when in operation from the power supply you indent to use, then they should also be fine to heatshrink.

 

[solidshark91493]

1/4 w is pushing it for covering in heatshrink. However it does depend on whether the LEDs will be a t full brightness and for how long. If your controller uses PWM and keeps the average brightness low, it may not be too much of an issue. Also the leads of the resistor will provide some heatsinking.

If they remain cool to the touch when in operation from the power supply you indent to use, then they should also be fine to heatshrink.

Ok this is great. Ill wire up one light with the power supply when it gets here and test it to see if it gets hot. if it doesnt Ill heatshrink it, if it does? Ill leave the resistor itself exposed but heatshrink the leads.

I have another question Id like to ask about my rgb led's But I dont want to make another thread. and keep the forum a bit tidier. if thats ok?

 

[(*steve*)]

Yes, I recommend you leave the LED on for an hour or so then feel the resistors. Depending on how hot they feel, we can discuss the options then.

Sure, ask more questions about your LEDs here. It's an appropriate place. If the discussion gets wildly different I can always move it to a new thread.

 

[solidshark91493]

Ok well I bought 600 of those leds about a year ago. I want to make a 8x8x8 rgb cube.
And I am struggling to understand how to make the circuitry.
Its based off of this circuitry.
http://www.kevindarrah.com/download/8x8x8/Cube_sch_3_16_13.pdf
it isnt my circuit, nor do I take credit for it.

Things I want to figure out:
1.Can it be simplified, or made better?
2.I want to integrate audio spectrum analyzing. To make my cube do stuff to audio input. Now whether this is something seperate I could attach, thats fine. I just dont know what im doing.
3. I want to fully understand how it works. I know because of my last couple threads I come out to be kinda noobish in this stuff. And I probably am but I have built a 4x4x4 led cube. Wasnt RGB, But still. I get basic concepts.

Any help would be Great!

 

[(*steve*)]

This may be a candidate for a new thread, but let's continue here for a bit.

Essentially, if you've done a 1 colour cube, a three colour cube is exactly the same except instead of wiring one set of anodes, you need to do three.

It's likely to end up as a much more busy set of wires.

There must be a youtube video of someone showing you how to do it -- surely!

How about this?

 

[solidshark91493]

This may be a candidate for a new thread, but let's continue here for a bit.

Essentially, if you've done a 1 colour cube, a three colour cube is exactly the same except instead of wiring one set of anodes, you need to do three.

It's likely to end up as a much more busy set of wires.

There must be a youtube video of someone showing you how to do it -- surely!

How about this?

Well, that is similar.. But I suppose I could link you to the build Im trying to emulate.
http://www.kevindarrah.com/?cat=99

I just want to get the first two questions answered mainly.

 

[(*steve*)]

In general, you can't simplify it. However I've not looked at the drivers in detail. There is a possibility you simplify them.

Sure, you could make some sort of spectrum analyzer. You might want to use one processor to control the display and another to do the signal analysis though.