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Topic: Connecting a 5V LED strip and 12V LED lights (Read 172 times) previous topic - next topic

dennisk23

Hi all,

So I just got into working with Arduino and wanted to change the lights on my 50cc scooter. It has a 12V 6Ah battery as power supply that I want to connect to the Arduino (only when key is switched to ON position, but I already know how to do this).

Now I have a WS2813 LED strip (with 20 LEDs) which I got to work the Arduino. I use this strip to have some fancy turning signal animation and DRL (daytime running light). Now I also have a T20 7443 LED which I want to control with the Arduino. This light has two settings (low and high beam) which both require 12V, and one ground for the two.

So my question is, how do I set this up?
1. Currently I connected my LED strip without a resistor, but do I want to add that in the "end product"?
2. I saw a video about connecting a 12V LED to the Arduino using a TIP122 transistor, so the LED is controlled by the Arduino, but uses the current & voltage of the battery, is this the way to go? I also saw a "Step Up Converter" which maybe could change an Arduino pin output to 12V but I think this will ask too much from the Arduino.
3. I read that using more than 12V as input for the Arduino could lead to damage, since the battery could potentially output 13-14V this is bad. I could just use a usb car adapter to power the Arduino, or is there something easier?
4. Do I need to add more resistors? Maybe for the 12V light (with 2 positive sides)?

To make things clear, what I have is:
WS2813 LED strip
T20 7443 LED light (with low and high beam)

5. Also this is for one side (turning signal) obviously, if I want to support both sides, is it better to do this with another Arduino, or should this be no problem with one? (Sure I need to change the program but that's no problem for me)

Any help is appreciated

DVDdoug

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1. Currently I connected my LED strip without a resistor, but do I want to add that in the "end product"?
I'm not exactly sure what that resistor is for and it might work without it, but it is recommended.

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2. I saw a video about connecting a 12V LED to the Arduino using a TIP122 transistor, so the LED is controlled by the Arduino, but uses the current & voltage of the battery, is this the way to go? I also saw a "Step Up Converter" which maybe could change an Arduino pin output to 12V but I think this will ask too much from the Arduino.
The concept is correct but a MOSFET will work better (lower voltage drop and less heat).   

But there's another complication...    The simplest transistor/MOSFET driver circuits are "low side" (AKA "ground side") switched.  that means the positive side is always powered-up and the lamp goes off (or is dimmed) by switching the ground connection.    That won't work with your high/low led/bulb.   

You'll need to find a high-side switch circuit, or you can use a relay if you have space for it.     With a regular electro-mechanical relay you need a relay driver or you can get a relay board with the driver built-in.  Solid state relays are another option, but make sure to get one that's designed for DC and one can be controlled with 5V.   With solid state relays you don't need a driver circuit.

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3. I read that using more than 12V as input for the Arduino could lead to damage, since the battery could potentially output 13-14V this is bad. I could just use a usb car adapter to power the Arduino, or is there something easier?
It would probably be OK if you were just powering the Arduino (opinions vary but I've done it).  But, you'll need a separate 5V power supply for the LED strip anyway so you can power the Arduino from that too.


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4. Do I need to add more resistors? Maybe for the 12V light (with 2 positive sides)?
I believe that's some kind of "12V automotive light" designed to replace a regular incandescent bulb,  so there should be a driver circuit (or maybe a resistor) built-in.


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5. Also this is for one side (turning signal) obviously, if I want to support both sides, is it better to do this with another Arduino, or should this be no problem with one? (Sure I need to change the program but that's no problem for me)
One Arduino can do it.   You should be able to use 2 output pins, but I've never used the WS2813 library so I can't help you with that.   Or, since the LEDs are individually- addressable you could wire them as one string.

dennisk23

Thank you for your answers.

1. So I think adding a 220 ohm resistor to the data pin of the LED strip should be fine.

2. I was searching for a 5V relay module board, but the only ones I could find said 250V 125V AC and 30V 28V DC, I assume the supported DC voltage is then between 28V and 30V or am I wrong?

3. Currently my LED strip gets power from the 5V pin of the Arduino when this is connected with USB. Should I do this in a different way?

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