Arduino Forum

Using Arduino => Project Guidance => Topic started by: tmacke17 on Feb 10, 2013, 02:41 am

Title: Car RGB LED Lights controlled with Arduino
Post by: tmacke17 on Feb 10, 2013, 02:41 am
Is this okay? I was wondering is it okay for one: to power my arduino from the car battery? Will it be too many amps? I'm just confused I the car battery part.. Will my arduino use the whole amp from the battery(along with the other things in the car)? I'm just afraid of the car battery frying my arduino.


My arduino will be controlling 3 TIP120 transistors.. 1 for each color. The amps o the LED bars ten selfs will be under 1Amp for sure..

Can I just get some advice on this?

Thanks
Macke
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: nickgammon on Feb 10, 2013, 02:49 am
Your Arduino won't use too much power, any more than your washing machine will suck in all the power generated by the power station and explode.
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: johnwasser on Feb 10, 2013, 02:51 am
Yes, you can use a car battery to power the Arduino.  The Arduino will only draw the power it needs.  The fact that the car battery can supply hundreds of Amps makes not difference.

The TIP120 should do a fine job of turning your light bars on and off.  They can handle 5A and 60V so they have plenty of safety margin.  

With a PWM pin you can fade a light on and off so the Arduino UNO can fade up to 6 lights.
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: CrossRoads on Feb 10, 2013, 02:52 am
Yes, you can power arduino from 12V. It will only draw the current it needs.
Many car sources are really dirty tho - I'd power the arduino from something like this to give yourself some protection.
http://www.cellphoneshop.net/minicar.html?cagpspn=pla&gclid=CKv2mrjQqrUCFQTe4Aodr0UA9g
Lots of versions exist, google "car usb charger"
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: larryd on Feb 10, 2013, 02:55 am
Quote
power my arduino from the car battery?

Yes
Quote
Will it be too many amps?

Place a 1/2 amp fuse between the battery and the Arduino.
Quote
Will my arduino use the whole amp from the battery

No
Quote
My arduino will be controlling 3 TIP120 transistors.. 1 for each color. The amps o the LED bars ten selfs will be under 1Amp for sure..

Use a 1 amp fuse for these.
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: tmacke17 on Feb 11, 2013, 02:05 am
Thanks a lot everyone! This forum is great.

So it sounds like the solution is fuses? If I need a total of say 2A for my LED bars I use a 2A fuse? And 1/2 Amp for arduino?

Also I forgot about wire gauge. My LED bars will be 20-22 Gauge wire. As long as I have the fuse, this won't matter will it?
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: tmacke17 on Feb 11, 2013, 02:11 am
Oh, also do i use the place with the circular jack and solder the wires from the battery to the jack connector for my power? Or do I put the car battery wires in Vnn? I'm always confused what Vnn is..

I'm not too much of a noob, but I'm still learning a lot, seeing is im 14. These are going in my brothers car, and I came up with the design

Also if anyone is interested, im building a box with switches, 5 of them, one for red, green, and blue, and then one for white(lighten) and one for black(darken) so I'm writing my sketch to say that if for ex. Red and white were on it would make pink, and blue and white would make cyan, etc. also, if all switches are on it will do a RGB fade through.

I'm having some trouble with the sketch, so I might be on here again..

But anyways, thanks a lot everyone, those were some of the best answers I've had on this forum, some people are just smart-alecs.

Thanks!
Macke
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: Quick5pnt0 on Feb 11, 2013, 02:55 am
Yes, VIN is where you input your power source, you can also put it in the power jack as well. Both will be regulated to 5V through the onboard regulator.
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: johnwasser on Feb 11, 2013, 02:58 am

Oh, also do i use the place with the circular jack and solder the wires from the battery to the jack connector for my power? Or do I put the car battery wires in Vnn? I'm always confused what Vnn is..


The Vin pin connects directly to the input to the 5V regulator.  The center pin of the power jack goes through a protection diode to the input to the 5V regulator.  Either one will work if you get the polarity right (Vin is +, Gnd is -).   The advantage of the power jack is that nothing gets fried if you hook the power up backwards (because of the protection diode).
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: tmacke17 on Feb 13, 2013, 03:24 am
Haha yeah I understand now. That's what I thought Vin was..

Thanks a lot again for everything!

One more clarification, so with the 1/2A Fuse, I just connect the 12V from the battery to either the power jack or vin?

Thanks
Macke
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: johnwasser on Feb 13, 2013, 02:50 pm

One more clarification, so with the 1/2A Fuse, I just connect the 12V from the battery to either the power jack or vin?


Yes.  And connect the negative side of the battery to Gnd (either a Gnd pin or the barrel of he power jack).
Title: Re: Car RGB LED Lights controlled with Arduino
Post by: tmacke17 on Feb 14, 2013, 03:59 am
Once again, thanks alot, everything is clearified for me now..

This forum is great!

Thanks!
Macke