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16  Using Arduino / General Electronics / Re: Lighting 8-12v RGB led with arduino on: April 29, 2013, 06:00:32 pm
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That's theoretically correct but, again, it's not appropriate to drive LEDs without current limiting. The best solution is a constant-current LED driver.

yes! I plan to build this: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
I was refering on Vcc and GND of that circuit! Sorry.

Thanks! I am good to go I think...
17  Using Arduino / General Electronics / Re: Lighting 8-12v RGB led with arduino on: April 29, 2013, 05:09:21 pm
no, wait, now I have another question.

as I explained:
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And I noticed that the RGB leds have a common anode (positive) and 3 different catodes (negative), so how can I connect two of these leds to 12v and the other to 6-8v if they have the same anode?

Could I connect positive to 12v and then connect negative of Green and Blue to 0v (ground) and Red to 6v? is this correct? I'm thinking I will have 12v-6v=6v on Red led. Is that correct?
Thanks again!
18  Using Arduino / General Electronics / Re: PWM Dimming non dimmable led drivers. on: April 29, 2013, 02:40:15 pm
what about building one of these? http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
Just got my RGB leds and I am onto that.
19  Using Arduino / General Electronics / Re: Lighting 8-12v RGB led with arduino on: April 29, 2013, 02:38:21 pm
genius, thanks!
20  Using Arduino / General Electronics / Lighting 8-12v RGB led with arduino on: April 27, 2013, 07:12:17 pm
This is the led I have: http://www.alibaba.com/product-gs/712130845/10_Watt_RGB_LED_high_power.html
These are the led input voltage:
RED -> 6-8V
GREEN -> 12V
BLUE -> 12V
And I noticed that the RGB leds have a common anode (positive) and 3 different catodes (negative), so how can I connect two of these leds to 12v and the other to 6-8v if they have the same anode?
Do I need to have 6v or something in the catode of the RED led for it to have --> 12v - 6v = 6v?

Thanks!
21  Using Arduino / Project Guidance / Re: Help with 10Watts color organ on: March 21, 2013, 09:17:38 pm
I got thinking and what if instead of connecting the "+V" of each color driver to 5V, I connect it to an Arduino pin and then if I turn it off then even if there is voltage on PWM pin, the led will remain off, right?
For reference see the driver here: http://www.tbideas.com/blog/img/schema1.png
22  Using Arduino / Project Guidance / Re: Help with 10Watts color organ on: March 21, 2013, 09:10:42 pm
Thanks for answering, mjkzz.

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1. I think general approach is sound, ie, control pin -> cc driver --> led
Ok, in that case I think the schematic is fine.

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3. No unless you constantly shifting outputs, you can't feed PWM signal to shift reg and expect PWM signal out.
You can use this library: http://www.elcojacobs.com/using-shiftpwm-to-control-rgb-leds-with-arduino/
I tryed it and it works!

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4. I think it would slow down your process if you want to maintain flicker free light output. There are some discussions over LED board and you can off load PWM job to a specialized chip, don't remember what it was :-)
Yes, maybe two shift registers to get 12 PWM outputs is too much and will slow it down too much.

I was thinking to use only 6 PWM outputs, in order to get only 2 colors, one color for a pair of leds and the other for the rest two. But now the question is:
How can I do some kind of ENABLE so even if I'm sending color voltage to the three pins on a led, it doesn't turns on if I'm not enabling it???

Thanks again.
23  Using Arduino / Project Guidance / Help with 10Watts color organ on: March 21, 2013, 03:46:36 pm
I already implemented a color organ with 4 leds. You plug a music input and it turns on the leds as the music goes (one led for bass, other for mid-low, other mid-high and other for highs) and it works fine. It uses Fourier Transform to get the spectrum of the sound.

What I really want to do is use four 10watts RGB led lights instead of 4 simple leds so I can light up a room. I know this RGB leds have 3 pins (one for each color) and can be driven by PWM, if the input of the 3 pins is zero, then the light is off.
And I also know I need a driver to turn a one color led on, like this one: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
I think I need three drivers per led as these are RGB, and also as there are only 6 PWM outputs on Arduino, I need a shift register, like this one: http://www.elcojacobs.com/wp-content/uploads/2012/08/shiftpwm_74hc595_RGB.png

Questions:
1- Are the general connections of the schematic ok?
2- If the led is RGB I need three drivers per led, right?
3- Will the shift register work ok?
4- Do you think that PWM shift register will slow down considerably the speed of Arduino? Because Fourier Transform is sensible to the speed.
Thanks a lot for your time!
24  Using Arduino / General Electronics / Re: Simple (I think) problem with very basic drum machine trigger on: March 07, 2013, 06:53:22 pm
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Could we talk you into replacing the whole circuit with an Arduino ?  smiley-evil
hehehe... I'm trying to simplify things to make it small. I was planning to do it more complicated later after I finish this one.

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Forget the diodes and put another buffer between the base trigger and the input circuit.
I am very amateur at this... Do you mean to double negate the output of the bass trigger? I should point out that at this point it does work as intended when the rhythm switch is connected into one of the counter outputs, but maybe it can be damaged if left for a long time?

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If you need that manual trigger then turn that buffer into a logic gate. The type will depend on the normal state of the output of the 74LS93. If it is normally low then an OR gate should do. You should connect the input of the OR gate through a potential divider to get a safe input level to the gate. You should not feed over the supply voltage into a gate.
I really don't know what is the normal state of the 74LS93 counter is, the 555 timer is always running. I am sorry but got lost here, what OR gate? I know what it is, but there is none here... I think.

Thank you again for answering, it's not the first time you help me, Grumpy_Mike.
25  Using Arduino / General Electronics / Simple (I think) problem with very basic drum machine trigger on: March 07, 2013, 03:31:40 pm
Okey, I originally posted this on http://www.edaboard.com because it has nothing to do with Arduino, but as I couldn't solve it there and I think that Arduino forum has a lot more activity than the other one, and also there is a lot of people here that knows this stuff very well and helped me in the past. So I tried posting it here.

Thank you very much for taking the time to read this and help me!

I designed this circuit which I think is a pulse generator, made with a 555 IC, counter and an inverter to generate a ryhtm for the drum machine
Out of the picture (down) is a hi-hat circuit.

(those two things drew on the right by hand are buttons)
First of all this part is working fine, it generates a desired pulse and is having no problems by itself, also the hi-hat works fine in rhythm.

I also made two PCBs for this circuit:
which generate the snare and bass sounds and connected each one (bass and snare triggers) to the designed pins on the right of the first image. That also works fine by itself with the rhythm.

As I also want the drum and snare to be triggered by a button when the snare and bass rhyhtm is disabled (by disconnecting the switch on the right of the first image, next to the snare and bass rhythm output pins, labeled "X2_RITMO(OPC)") so I also connected a button to +9v and the other pin of the button to each trigger and THATS WHERE THE PROBLEM IS.

When I press the bass button it first triggers a bass drum sound, but when I realease it it makes a snare drum sound, also it seems that the snare button doesn't trigger the snare at all.


On the other forum a user kindly suggested I should put a diode in the bass wire, so that none of its switch action gets back to node 3.

So I made this modification:
but now it behaves in a weird fashion, when I press the bass button it makes the snare sound like a machine gun firing it very rapidly.

Any ideas what I could try? Thanks a lot!!!
26  Using Arduino / LEDs and Multiplexing / Re: CD4051 Multiplexor input test sketch on: October 31, 2012, 05:58:44 pm
Yes, I know it's not efficient but it's just for testing a connection to a MUX, works for me.
Code:
2. You may spuriously select two wrong channels before settling on  your target channel.
Sorry but I don't understand, what do you mean with this?
27  Using Arduino / General Electronics / Re: Soldering leads to arduino to finish up? on: October 31, 2012, 05:57:14 pm
today I removed the female plastic for the pins and after getting something as the Diavolino as fungus is showing us then I soldered the cables directly to it
I think that is better than gluing them
28  Using Arduino / General Electronics / Re: Audio out and speaker on: October 29, 2012, 12:24:02 pm
Hey, thank you very much to all for the great help and the time!
I think I got it now, the jack will act as a jumper when a plug is connected, that goes in series to the speaker.

I'll buy some from ebay!
29  Using Arduino / General Electronics / Re: Audio out and speaker on: October 28, 2012, 07:21:57 pm
ok, yes, but where do I connect the switch output of the jack?
30  Using Arduino / General Electronics / Re: Audio out and speaker on: October 28, 2012, 01:12:44 pm
ok, and where the switch of the audio jack goes connected on that schematic? If it were a normal switch I would think that the switch goes from R7 to speaker, but I have no idea how to do it with a built in switch as it has only one connector.

also, I dont see R7 value and what value should be correct for the R9 potentiometer?
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