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Author Topic: Any Heating issues?  (Read 328 times)

Online whb64

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Any Heating issues?
« on: April 22, 2017, 12:33:31 am »
Are there any heating issues?

Also any long term problems running it on 12vdc?  My LED light strips are 12vdc and I would like to have one power supply for everything.

Offline LynnInDenver

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Re: Any Heating issues?
« Reply #1 on: April 22, 2017, 09:16:31 am »
I have a couple of recommendations:

First, the 12V LED strip lighting should be able to be run at 9V. It'll run dimmer, but it should help it be more "in scale".

Second, you need to build a circuit for the base that you can use to make 5V rails off the 9-12V coming in. The Atmel chips used for Arduino are only rated up to 5V, even 9V will pretty much destroy them instantly. Go ahead and run 4 lines into the model - 2 for the +/- on 9 or 12, 2 for the +/- on the 5V. Run the bulk of the lighting off the 9-12, and run the Arduino circuits specifically off the 5V. A simple step down circuit for this can be made with a 7805 transistor and two capacitors. If you're feeling really salty, you can go further and get the circuit to do the same sort of job, but drop it down to 3V, since the chip will run as low as 1.8, and the LEDs top out at 3V for the white and 2V for the colors anyway. You can buy premade "buck converters" for this job. And do note, you do NOT want the step down for that current to be housed inside the model, because it WILL generate more heat.

Offline simi

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Re: Any Heating issues?
« Reply #2 on: April 22, 2017, 11:46:24 am »
I have a couple of recommendations:

First, the 12V LED strip lighting should be able to be run at 9V. It'll run dimmer, but it should help it be more "in scale".

Second, you need to build a circuit for the base that you can use to make 5V rails off the 9-12V coming in. The Atmel chips used for Arduino are only rated up to 5V, even 9V will pretty much destroy them instantly. Go ahead and run 4 lines into the model - 2 for the +/- on 9 or 12, 2 for the +/- on the 5V. Run the bulk of the lighting off the 9-12, and run the Arduino circuits specifically off the 5V. A simple step down circuit for this can be made with a 7805 transistor and two capacitors. If you're feeling really salty, you can go further and get the circuit to do the same sort of job, but drop it down to 3V, since the chip will run as low as 1.8, and the LEDs top out at 3V for the white and 2V for the colors anyway. You can buy premade "buck converters" for this job. And do note, you do NOT want the step down for that current to be housed inside the model, because it WILL generate more heat.

Yes, what Lynn said.  The arduino can control the "gate" for the 9 or 12v rail - but it shouldn't go through the arduino.  The arduino is the "brains".  You'll get a pretty fast smoke-check if you do put that amount of voltage through it!

Cheers!

Simi
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Online whb64

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Re: Any Heating issues?
« Reply #3 on: April 22, 2017, 12:06:40 pm »
I have a couple of recommendations:

First, the 12V LED strip lighting should be able to be run at 9V. It'll run dimmer, but it should help it be more "in scale".

Second, you need to build a circuit for the base that you can use to make 5V rails off the 9-12V coming in. The Atmel chips used for Arduino are only rated up to 5V, even 9V will pretty much destroy them instantly. Go ahead and run 4 lines into the model - 2 for the +/- on 9 or 12, 2 for the +/- on the 5V. Run the bulk of the lighting off the 9-12, and run the Arduino circuits specifically off the 5V. A simple step down circuit for this can be made with a 7805 transistor and two capacitors. If you're feeling really salty, you can go further and get the circuit to do the same sort of job, but drop it down to 3V, since the chip will run as low as 1.8, and the LEDs top out at 3V for the white and 2V for the colors anyway. You can buy premade "buck converters" for this job. And do note, you do NOT want the step down for that current to be housed inside the model, because it WILL generate more heat.
Thanks for the tips

So if I understand this I either need to tap off from my 12vdc PS (inside the base) and run that to a 5vdc regulator and then run 4 lines to the model.  3 should work- +5vdc, +12vdc and one common, but it won't hurt running an extra line in just to keep things isolated.  This should work nicely since I'll just be running the strips and Arduino board.  Question... if I drop it to 3vdc will I even need resistors?


Offline MarkW

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Re: Any Heating issues?
« Reply #5 on: April 22, 2017, 12:58:07 pm »
It would help to know a little more about what you intend to do.  It would be just as easy to control the 12V strips through a transistor setup.  I've been feeding arduous off the "raw" pin which can handle the 12V input just fine.  You can then control multiple separate 12V feeds via transistors.  I also agree running 12V lights at 9 V works better in scale.
MarkW
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Offline LynnInDenver

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Re: Any Heating issues?
« Reply #6 on: April 22, 2017, 01:20:51 pm »
So if I understand this I either need to tap off from my 12vdc PS (inside the base) and run that to a 5vdc regulator and then run 4 lines to the model.  3 should work- +5vdc, +12vdc and one common, but it won't hurt running an extra line in just to keep things isolated.  This should work nicely since I'll just be running the strips and Arduino board.  Question... if I drop it to 3vdc will I even need resistors?

For white LEDs, you probably won't need (but should still use) resistors with 3V. For red/green/yellow/amber LEDs, you'll still need resistors to cut things down to around 2V. For reasons of overhead/margins, it's better to go resistors than try to drop the Arduino down to 2V; you can do it, but it doesn't leave a lot of room in terms of brownout. I've got a setup I'm working on for landing lights in a Battlestar Galactica model, and I've realized myself that it's 3V or 5V going in to drive it, or not bothering.

And for the negative leads, yeah, better to go ahead and run isolated for each voltage rather than try to combine them, it reduces the potential for issues down the line - cracking open a finished, sealed model to redo electronics and lighting sucks even at the best of times.

Offline Grumpy Popeye

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Re: Any Heating issues?
« Reply #7 on: April 24, 2017, 07:06:59 pm »
I run my Arduino Nano off 12V with no issues at all, driving 4 pairs of LEDs for my Republic Star Destroyer. It ran from 9AM-4PM this past weekend at my local(ish) IPMS show in Renton, WA

 




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