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16  Using Arduino / General Electronics / Re: Touch panel (made with PCB) on: May 06, 2013, 09:20:24 pm
mmm.... maybe something like this?: http://playground.arduino.cc//Main/CapacitiveSensor?from=Main.CapSense
but on this example you need 2 pins and I can see that that Touch&Spell has only one for the pitch control
17  Using Arduino / General Electronics / Touch panel (made with PCB) on: May 06, 2013, 08:23:25 pm
I stumbled upon this: http://casperelectronics.com/finished-pieces/speak-n-spell/touchandspell/
And was wondering how that touch panel made from conductive material works?
How can this be implemented in Arduino? I am more interested in the pitch control, if you connect it directly to an Arduino pin would you be able to do an analogRead and that's all?
Great webpage by the way.
18  Community / Exhibition / Gallery / Re: Simple Colour Change Lamp on: May 05, 2013, 10:57:00 am
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Apart from using different MOSFET and resistor values the circuits are the same
I mean the shaded parts, it says on the webpage that those parts are for "adding PWM input support", I built it without those parts and still works (even if it blinks a little when PWM is low)


19  Community / Exhibition / Gallery / Re: Simple Colour Change Lamp on: May 04, 2013, 10:22:04 am
What is the difference between the circuit you linked and this one?: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
Yours has extra parts for beeing PWM friendly as it says on the page, but I really don't understand the explanation.
I did mine and I noticed that when PWM level is low the led blinks a little, I really don't know if it will bother with the other colors turned on, need to test that.
Do you think adding those extra parts will solve that?

Thanks
20  Using Arduino / General Electronics / Re: Help with schematic (changing GND to 6v) on: May 04, 2013, 09:48:19 am
So if I only need to connect just one colored 10 watts led per driver do you think it's better to just have R1 and Q1?? Something like that?
One thing I noticed is that with a low width PWM (when the color should be off) it blinks a little. What do you think about that?
21  Using Arduino / General Electronics / Re: Help with schematic (changing GND to 6v) on: May 03, 2013, 07:54:40 pm
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That will work better using a voltage regulator for the Red.
Can you snip off the top of the device so you have seperate anodes for the 3 LEDs?
Then you can have 12V for Green & Blue, and regulated 8V for the Red, and the cathodes can connect to your circuit above.
You know what? I never tought trying to separate the anode of each led, but it can be done!!! That solves a problem. I tryed and now each color has it's own anode.
Sorry I forgot to add that it was a simplified circuit, instead of a resistor each color has it's own driver.

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I would switch to a forum where they didn't tell you such rubbish.
For a start that is not a proper circuit and second you always need one resistor per LED.
hahaha, a genuine Grumpy Mike! I think that forum is this one! Great community!

Thanks, you all!! I think I have everything covered!
22  Using Arduino / General Electronics / Re: Help with schematic (changing GND to 6v) on: May 03, 2013, 02:07:27 pm
I think this is the way to go, as someone in another forum told me:
I was thinking in getting 6v from 12v with something like this: http://schematic-audio.blogspot.com.ar/2011/10/dc-converter-using-7808-regulator-ic.html

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Why so convoluted?
Just drive with 3 logic level, low Rds, low Gate capacitance, N-channel MOSFETs
http://www.digikey.com/product-detail/en/NTD5867NL-1G/NTD5867NL-1GOS-ND/2401422
10k pulldown resistor to hold gate off while arduino starts up.
well... that will replace the whole circuit, right? I am certain that will not be able to find it here on my country (Argentina) :-(
23  Using Arduino / General Electronics / Re: Help with schematic (changing GND to 6v) on: May 02, 2013, 09:48:25 pm
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question is...

how much current to power the led is required?

that circuit is overkill... and yes the same circuit would be fine, r2 is doing the work to protect the diode.
Ok, the led is this one: http://www.alibaba.com/product-gs/712130845/10_Watt_RGB_LED_high_power.html
it is a high power RGB and as you can see on the table you need around 12v for BLUE and GREEN but you need around 6v for RED, and also the leds have a common positive pin.
As this is the case, I need to connect 12v on the positive side, and I was thinking that I could connect 6v on the negative side of RED instead of 0v so it has the required voltage.

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Where's the 6V coming from?  If you have a 6V supply, why don't you use it directly instead of trying to subtract?
I only have a 12v power source and I was thinking getting 6v from it with a voltage divisor (resistors), the question is if it will work connecting the RED driver to Vcc->12v and GND->6v.

The schematic I referenced on the first post is a led driver and I need one for each color (RGB, so three of them)
24  Using Arduino / General Electronics / Help with schematic (changing GND to 6v) on: May 02, 2013, 05:32:44 pm
Ok, I needed a driver for a 12v led and did this:
(full article explaining everything: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
Vcc connected to 12v and of course GND to 0v.

It works fine, but now I need the same thing but instead of driving a 12v led I need it to be 6v, but the thing is that because of design Vcc still needs to be connected to 12v.
My question is: Can I connect GND to 6v so the voltage difference of the led is 6v??? (12v-6v=6v)
Also do I need to change anything on the circuit??

Thanks!
25  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...
26  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:
Quote
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!
27  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.
28  Using Arduino / General Electronics / Re: Lighting 8-12v RGB led with arduino on: April 29, 2013, 02:38:21 pm
genius, thanks!
29  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!
30  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
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