How do I power Arduino Unos to several LED pixel strings from a generator?

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americanninjaworrier
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How do I power Arduino Unos to several LED pixel strings from a generator?

Postby americanninjaworrier » Fri Jul 28, 2017 11:46 am

First art car involving a lot of LED strings so I need a lot of power! But I'm so baffled on how to wire the power.

Here's the plan:
* A generator (Honda EU2000, AC output: 120V, 1600W rated, 13.3A & DC output: 12V, 96W, 8A)
* 4 Arduino Unos controlling several strings of addressable LED pixels. They're all 5v and 50 LEDs a string. One string draws a max of 2.4A, 12w. Total of 20 strings would draw (max) 48A, 240W.
* Not sure if it matters but some of the strings will have a 1 meter extension between them.

Here's where I'm confused:

1. If I need this much power, seems like this generator doesn't have the amperage....right?
2. How do I power the Unos separately?
3. How do I power the pixel strings? Lots of 5v, 10A power switching power supplies like this one? Or a 5v power supply like this one?

I have a sketch of how I picture this being wired. Does this make sense?
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Token
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby Token » Fri Jul 28, 2017 1:20 pm

You are terribly confuzeled.

You can literally power all this from two car cigarette lighter ports.

5V at 48A is same power as 12V at 20A is same power as 120V at 2A

So the Honda is massive overkill. It will basically idle.

Does your MV have a standard automotive 12V system? That should be plenty unless it's a lawn mower or somesuch.

Try powering 2-3 strings in series from a 12V battery. That would be either running the strings at 6-7V for two, or 4.5 to 4.7V for three.

If that pans out and you have 12V on your MV, there you go.

BTW, the 12V port on the Honda is UNREGULATED. Good odds it fries anything connected to it other than a battery, and I wouldn't do that either.

badscr
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby badscr » Fri Jul 28, 2017 1:56 pm

if there is a reason for the Generator to power it then, I would order Two of This one you listed above one to use and one for backup. (dont use the Generator 12V plug)

Token is right: the Gen is over kill if you can power from the car.
At first glance the string 3 in series sounds great BUT these are addressable RGBs and that would most likely cause problems with the Current flows and then Voltage drops across would change. = bad

i would order 5 of these DC12V(10V~32V) Step-Down(buck) to DC 5V 30A 150W that would be 1 per Uno and strings + 1 spear and you would have some fudge room.
You can Tie all the Grounds together if you like.


What ever u decide. Supply the power at the start of the strings and the End of the strings also at each extention part too.
that will give you good & even power distribution, and alot less chance of Dimming/strob from power draw transients.

the uno is 5V comaptable so just give it the 5Vdc from the Strings
Last edited by badscr on Fri Jul 28, 2017 3:53 pm, edited 1 time in total.

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Admiral Fukkit
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby Admiral Fukkit » Fri Jul 28, 2017 3:50 pm

Not enough info to know if the generator is overkill.
240 watts is VERY minimal for lighting anything but the tiniest mutant vehicle.
Chances are either this isn't an automobile-based MV, or it has other power needs besides just this.

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BBadger
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby BBadger » Fri Jul 28, 2017 5:06 pm

Your generator provides AC power, about 120V at like 5 amps when you're in eco mode (400W). Watts = volts_rms * amps. Each of your Arduino and strip pairs use DC power, at about 5V and maybe 3 amps. That's 15W of power at max. Even with 20 of those things you're only using 300W or something.

To power that setup, buy yourself some cheap 5V DC, regulated power supplies rated for like 2-5 amps like this or that or the ones you listed. I linked you to a 2A power supply because that 2.4A is the very maximum amperage those strips you're using will consume; however you will rarely if ever reach that because it means full-on bright white, which you probably will never do.

Plug those 5VDC power supplies into the AC power outlets coming from your generator like you would from wall power. Don't bother with those DC outputs on your generator. You can connect the DC power from the power supply's barrel connectors to your Arduino and lights by using some barrel connector adapters like (these. Don't pass power through the Arduino to your LED strips, instead provide separate connections for power and ground. Make sure the grounds are shared for each respective pair or you'll have bad signals.

For longer distances, use extension cords from your generator to go longer distances to your Arduino/strips. Don't provide the 5VDC power long distances. The AC power is better for longer distances because of the higher voltages and lower currents involved.

Looking at your diagram above, I would not chain strips end to end to power them as the strips cause voltage drops over distance. Instead, provide a separate DC power connection with wire if you have enough amps on that power supply; otherwise, use another power supply. Remember to tie your grounds together for each separate strip-power-Arduino network.

Your generator is way more than sufficient. You could even probably get away with batteries depending on the patterns and such. I have personally powered about 2400 LEDs over about 12-15 strips worth of power, including computers and PSU inefficiencies, and the total power usually averaged less than about 60W. Generally you won't be displaying extremely bright patterns, so you'll never reach your limits. That said, I did spec my power supplies to provide 600W total if needed, which it may have in short bursts, but even then I doubt it. I ran on eco mode all the time and the gas lasted way longer than the 9 hours it was supposed to give per fill-up.
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some seeing eye
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby some seeing eye » Fri Jul 28, 2017 6:39 pm

LEDs take less power and are of course less bright when cycled on an off at a rate the eye cannot detect. You might look at the timing diagram for those LEDs and research brightness control by pulsing. If you used one Arduino you could pulse strings in sequence to save power. Theoretically...
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some seeing eye
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby some seeing eye » Fri Jul 28, 2017 6:39 pm

Trying to coordinate multiple Arduinos to cooperate in alternate cycling might be difficult.
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americanninjaworrier
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Re: How do I power Arduino Unos to several LED pixel strings from a generator?

Postby americanninjaworrier » Mon Aug 07, 2017 12:23 pm

Thanks for the help, everyone!


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