doesnt that ruin the voltage differential through the line making there be zero voltage drop across the LEDs from the beginning to the next place where i hook up the 12 V+?
That is exactly what you want it to do. You want there to be no voltage difference between one +12V and the next. The voltage differance that drives the strip is between 12V and ground.
Oh so are these LEDs powered by 12volt drops? meaning each individual LED needs 12volts to operate? That would make sense as to why you need it near 12 volts at all points. I was just confused because i though that the electricity didnt hit ground until it went through the very last LED.
The normal way of powering these strips is to have a 2A power supply every so often on the 12V line.
Make no mistake so any LEDs is not a simple or trivial project. You are a beginner so you don't know what is easy and what is not.
If i am not mistaken (given what i know about basic electronics), if i take a 2A power supply at 12V, and i connect it to multiple points along the length of the 15meter LED strip, then the current will not be 2A at each point where i connect it
You can get an SD card shield or solder one on. Again google it.
Will do, thanks!
Even 900 LEDs is 18 amps, that is a lot of current and at 12V is over 200W, that is a lot of light to spread over a ceiling, get your sun glasses out.
Uh oh... Now you are scaring me. What kind of power supply am i going to need to run this thing? Is this too much for a beginner? Could someone link me to an example power supply one might buy to power this thing?
I know how the connections work, but if i have to connect the the Voltage + terminal of the LED strip every few meters doesnt that ruin the voltage differential through the line making there be zero voltage drop across the LEDs from the beginning to the next place where i hook up the 12 V+?
The point is the very opposite. You do not want
a voltage "differential" along the supply lines. The copper foil tracks on the LED strips have a comparatively high resistance. If one amp is flowing every tenth of an ohm introduces a 0.1V drop, and the resistance of that foil over a two meter length will be a few tenths of an ohm. You need a much more sturdy wire, at least the gauge of that in an average power cord, paralleling the LED strip and connecting into the Vcc and ground, each two metres. Note that this will feed current in both
directions, forward into the next two meter section and back
into the second metre of the previous section. Fed in this fashion, there will be a small drop in the total voltage available halfway between the two ends, but if my rough analysis is correct, significantly less
than half the drop that would exist at that point if power was not being fed back from the other end of the given two metre section.
Ah, I didnt realize that these LEDs operated at 12Volts, that makes sense then that each one needs to drop 5volts to ground. I was under the impression that the 12volts dropped to zero across the entire length of the strip (not hitting ground until the last LED drop. So you are saying that each LED needs 12volts, at some amperage, and in order to supply the correct amperage to each LED i need to hoot it up every 2 meters or so? Please correct me if i am still mistaken.
I never though of using an SD card to hold the patterns! Can you hook up an SD card to an arduino to use an more memory? And how would it hook up to a standalone arduino or arduino mini pro? Do i need to solder the SD card to the board?
You use a socket. Three are shields available for the UNO/ Mega format for this purpose, but I believe you could simply wire a socket to the necessary ports and power. There are no necessary interface components (apart from a bypass capacitor) AFAIK, but I believe the SD cards use 3.3V.
Okay i will look into that more, I assume there is also some library for writing and reading from the SD card? Or is the arduino smart enough to know to use that extra memory?
Where are you getting 1700 LEDs from? 60 per meter for 15 meters is only 900 LEDs. Also i am curious, does this mean i cannot do this project without having a hulking piece of copper lining my ceiling also? I feel like it should be that hard to power 900 LEDs, certainly requires some power, but not huge pieces of metal.
Eighteen amps is not insignificant. For starters, you need to use cable at least
as heavy as you use for your 1800W electric radiator, but you generally do not care about losing a volt or two at 110V. At 5V, you really do
care about how many volts (or fractions thereof) you lose.
Jesus, that sounds a lot scarier to me than i though this project was going to be. I am a little worried about something going wrong now because i dont really know how i am supposed to connect the power supply to the strip. What does a power supply like that look like? And how do i go about safely attaching it to the LED strips? I have never used any wires larger than 20 gauge. What kind of wire will i need to hook this up?
This is turning out to be a larger beast than i thought it would be.
Also just to note, I have found a seller on alibaba that is supplying individually addressable WS2812B LED strips that run at 5 volts. Is this better or worse? It is 60LEDs per meter and they are rated at 14.4Watts/meter and have an Epistar SMD 5050RGB LED. Is this good for what i want to do? Or is there something fishy about it?
EDIT: I just checked around and apparently the individually addressable LEDs typically run at 5volts, instead of 12volts like the non-addressable ones. Why is that? Is there a reason that the individually addressable ones run on 5VDC instead of the non-addressable ones that run 12VDC? And how does running at 5VDC change the way i need to connect the power supply?