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Topic: Powering light strip from arduino? (Read 1 time) previous topic - next topic

Hey guys,

I recently accomplished at making led lights light up to music, was proud of that :)

I now face a problem with powering a strip of 30 LEDs, looks a bit like this: http://www.acmelite.net/images/1/p/R30X_S/led-strip-light-R30X_S-2930.jpg

From what i see on different suppliers, this strip of lights require 12V, is there any way i can provide that much voltage from arduino, or anything close to it?

Unfortunately, i have no information on my strip of lights...

Sorry, if this is a poor question, i am only a beginner.

Cheers,

Phil.

johnwasser

Use and NPN transistor or an N-channel MOSFET to switch the voltage and current.  See this tutorial about high current 9and voltage) loads: http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads
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Grumpy_Mike

You can't power the strip from the arduino but you can control the strip from the arduino.
There is an important distinction there.

Thanks Mike,

I found that the strip needs 12V.

Would i use a transistor to make this work?

I have a couple 2n2222 transistors and UA741CN Op Amps, would those work?

Thanks.

Grumpy_Mike

Quote
I have a couple 2n2222 transistors and UA741CN Op Amps, would those work?

Probably not.
The 741 is a very old op amp and has no role in controlling an LED strip.
The 2n2222 can only handle 500mA of current or so. What current does you LED strip take?

The packaging states 12V DC and 24W, so... 2A? (ohms law).

Grumpy_Mike

Seems a reasonable assumption.

You are best using a logic level FET to switch this.

Any specific one?

I have never used and know basically nothing about those transistors, whats the basic difference in the field effect type? i would have to do some research while i'm at it.

From what i understand so far, you tell me to use a FET since it has a huge resistance, allowing for practically any current to go through and not damage the semiconductor?

Grumpy_Mike

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FET since it has a huge resistance,

No it has a very small resistance.
Try reading this:-
http://reibot.org/2011/09/06/a-beginners-guide-to-the-mosfet/

Which FET should i buy, doesn't seem like anyone at the store was able to assist me... :\

Grumpy_Mike

You want an n-channel logic level FET.
That is one where they specify the on resistance Ron at a gate voltage of 5V or so.
Most FETs need 10V on the gate to fully turn them on.
Do not mix this up with a gate threshold voltage of 5V as this is the point where the FET just starts to switch on.

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