If you try to draw more than half an amp of power (easy with lots of LEDs) from an Arduino Nano’s “+5v” pin, the board’s power regulator overheats. This means that even if the board is being powered from a 2 Amp USB power supply (e.g., an iPad charger), you can’t easily use all that power. This short How-To shows how to route the full two amps directly from the USB power supply into your LEDs.
EXTRA WARNING: if you build a setup that actually can draw 2A from a USB port, DON’T POWER IT FROM YOUR COMPUTER. Computer USB ports (in general) can’t supply that much amperage, and you’ll get into trouble. Relatedly, Dan and I tend to have a delay(3000) at the start of our sketches to help prevent eternal stuckness – which we’ve had before.
There are, of course, dozens of other ways to power a bunch of LEDs from a 2A USB charger, but this trick has turned out to be surprisingly useful and compact for me.
Any idea what the trace width is that is carrying the 5v to the regulator? Or copper thickness? When I was making my pixel boards I wanted to pull 3A off of the power supply and needed a very wide trace to handle it something like 70mil w/ 1oz copper.
I did notice your warning Made me laugh. I’ve had a couple of times when I left 50cnt 5v pixel strings connected while programming and the only power was the ftdi programmer and still haven’t fried it yet and no magic smoke was released
No idea on the specs-- this has been strictly empirical.
I bet you could look up the info from the Nano’s board files; copper thickness probably varies with manufacturer.
I’ve found a nice supply of under-$10 Nanos, and haven’t fried any (this way) (yet). On the other hand, all but one of my projects tends to run more in pure hues (1/3rd power) than in desaturated bright whites. But even then, I’ve run 60 pixels at nearly full white for many hours this way, and so far no fire.
I know you mentioned that one should use a 2.0A USB charger. May I suggest you make this very clear, with big fat bold red letters: DO NOT USE YOUR COMPUTER USB PORT. While it may happily charge your phone or iPod, it only provides 500mA (USB2.0) or 900mA (USB3.0). A USB charger however can range from 2A to 5A, it depends on the charger / manufacturer.
I am more and more coming to think of LED/art projects as having three big "P"s: Pixels (the LEDs/hardware), Programming (software/integrations), and Power.
it’s kinda nice now you can also cut both wires same size for power, and strain relieve against the board. Nice hack! I will try it on my next nano assembly
Made me laugh. I’ve had a couple of times when I left 50cnt 5v pixel strings connected while programming and the only power was the ftdi programmer and still haven’t fried it yet and no magic smoke was released