What do I need to power up 81 High Power LEDs?

[Anonymous No.1079781]

Until now I've done simple serial circuits or step-by-step projects, now I want to make a paralel circuit with 81 LEDs, 8 different colors (Red, Orange, Yellow, Green, Blue, White, Pink and Violet)
I now little about resistors or the voltage I need. Any help? I need to finish this in less than a month.

[Anonymous No.1079786]

>>1079781
Ok well where the fuck to start
The ' effective resistance' of an led decreases as it heats up, a warm led draws more current which causes more heat. This is called thermal runaway and it kills leds. That's why you need a resistor.
The resistor value is determined by the difference in voltage between the source and the led (the voltage that the resistor will have to drop (voltages add up in a series circuit and are equivalent in a parallel circuit, google kirchoffs laws)) and the current the led needs (again, thanks kirchoff) then you use ohms law r=v/i (voltage in volts divided by current in amps gives resistance in ohms).

If you want to drive lots of leds you can put them in series, one after the other, but because of kirchoffs laws they all draw the same amount of current, you might want to be careful putting different colours in series because they might need different currents. You need one resistor for a series circuit.

You can put leds in parallel but each led will require a resistor to set the current.

Then the next step is to put sets of series leds in parallel.

So r=v/i where v is source voltage - led voltage ( add up led forwards voltage for leds in series)
Oh also for resistors you should find out the power, multiply the voltage over the resistor by the current through it, the resistor needs a power rating in watts higher than the value calculated. Usually resistors are 1/4 watt, high power leds that draw a lot of current might need beefy resistors maybe 1 watt or more.

Play with the wizard for some practice
http://led.linear1.org/led.wiz

[Anonymous No.1079800]

As a Led enthusiast/fag I approve on this thread fully!

[Anonymous No.1079802]

>>1079800
Nice room you got there, nice work

[Anonymous No.1079805]

>>1079802
Oh, well thank you! My entire apartment is led outfitted. The only normal light I have is on the balcony

[Anonymous No.1079812]

>>1079805
do you have any troubles with that?

[Anonymous No.1079896]

> 8 different colors (Red, Orange, Yellow, Green, Blue, White, Pink and Violet)

Why though? You can get all the colors by mixing red, green, and blue. If you just control them with on/off you can get white,yellow,pink, cyan. If you control them with PWM dimming you can get anything on the color wheel. Your colors will be brighter this way because pink will be from turning on all your red and blue LEDs, instead of just 10 pink ones.

> I now little about resistors or the voltage I need. Any help?
Use this: http://led.linear1.org/led.wiz
It will design your circuit for you.

I don't really know what you mean by "high power LEDs" since LEDs labeled "ultra bright" are low power compared to Cree LEDs, and those are low power compared to some even brighter ones... Using resistor circuits is suitable for LEDs less than half a Watt such as 20mA 3v ones. Higher than that and you start needing to use those big expensive high power resistors and worrying about having enough air flow to cool them. It's better to use a switching current regulator system instead.

[Anonymous No.1079907]

>>1079781
You need to provide more information.

Mostly, are you just going to be turning all 81 LEDs on at once, or are you going to be turning them on and off, or are you going to vary the intensity?

If there's any variation, then how many channels, how many LEDs on each channel, etc?

For high currents, you ideally want to be using a switching (buck) regulator rather than a resistor or a linear current regulator. But if you have many channels, one regulator per channel translates to a lot of extra components.

And as >>1079896 suggests, for multi-colour you'd normally go for RGB LEDs.

The biggest issue with power LEDs (as in, designed for illumination, not just "bright" LEDs) is thermal management.

LED lamps typically have a bunch of thermal vias underneath the part to conduct the heat to a heatsink on the other side of the PCB. That's a nuisance for DIY PCBs; one solution is cutting a large hole under the LED and filling it with a copper disc.

[Anonymous No.1079936]

http://bob64.tumblr.com/post/34030687237/marisa-kirisames-mini-hakkero-v2-prop
This is what I'm trying to make for a friend, she needs it for a cosplay

[Anonymous No.1079968]

>>1079907
At once, for as long as I can

[Anonymous No.1080021]

>>1079907
8 channels, 9 LEDs per channel

[Anonymous No.1080032]

do it properly and use a constant current source

[Anonymous No.1080066]

>>1079896

I don't understand why people don't build their own LED controllers.

[Anonymous No.1080099]

>>1079812
No problems at all, everything is controlled individually or group.

[Anonymous No.1080210]

This is the final outcome of what I need

[Anonymous No.1080212]

[Anonymous No.1080389]

Shameless bump

[Anonymous No.1080425]

I can't "resist" shitposting lmao

[Anonymous No.1080427]

>>1080425
4700 ohm resistor

[Anonymous No.1080846]

I did this today, 9 red LEDs, still don't know how to connect them to the 72 other LEDs or how much resistance I should apply

[Anonymous No.1081834]

>>1080846
>how much resistance
As much as you want. Everything above 50 or so ohms should be fine to not ruin the LEDs, add more if you want to reduce brightness and prolong battery life.

What's your problem with hooking them up? If you use a battery pack like >>1080212 you just hook up 3-5 LEDs in series (depending on forward voltage), together with a current limiting resistors. Those series strips you then simply hook up in pralell.

[Anonymous No.1081836]

Is this some tony stark shit again?

[Anonymous No.1081925]

>>1081836
Worst, Touhou Project

[Anonymous No.1082961]

>>1079781
You don't use current limiting resistors, you use a constant-current switching power supply, or a PWM white LED driver.

[Anonymous No.1082989]

>>1079781
Learn how to count first. That is 64 LEDs.

[Anonymous No.1083700]

>>1082989
>Learn how to count first
72

[Anonymous No.1084130]

Related but not OP
How much do you have to worry about heat with LEDs?
I'm going to embedded strips into EVA foam and don't want to worry about them melting the foam.
The LEDs will be between a PVC core pipe and eva foam. Do I have to wrry about melt?

[Anonymous No.1084249]

>>1084130
Depends on what kind of LED you're using. A 1W COB LED will obviously dissipate more power than a generic 3mm LED underrun at 10mA.

[Anonymous No.1084320]

>>1084130
I did a mask made out of EVA foam with LEDs, everything is ok

[Anonymous No.1084338]

>>1084249
I think theyare 1 W
so hoping that's not a problem
>>1084320
and right on thanks

[Anonymous No.1084341]

I don't want to open a new thread for this for now so I'll ask here:
I come over from /p/ and I want to make a powerful, portable Video-Light. Most DIY LED projects on youtube are just professionals trying to 1up each other with increasingly unnecessary ammounts of Lumens. SO I need to ask for a good instruction manual on here.
I want something capable of 1000-2000 lumens, not bigger than a standard flashlight. I would power it with AA Eneloops, since I have lots of those. It needs to be dimmable and have a diffusor (I would have just taken a cut-open ping-pong-ball, if you know better, let me know)
I dont have access to a lot of tools, but most forms of screw-stuff, a set of PC-screwdrivers, a powerdrill, tweezers, plyers, boxcutters almost all of them shared and of medium or worn quality. a roomate of mine can solder.
I live in mainland europe so I only have access to metric stuff.

[Anonymous No.1084649]

>>1084338
1W LEDs need a heatsink, at least they almost always come with one in flashlights.

>>1084341
You get about 200 or so lm per watt so what you're looking for will be quite beefy.

I'd start out with searching suitable COB LEDs and an adjustable PWM driver for them.

[Anonymous No.1084826]

>>1084649
I'm technically trying to reproduce this:
https://www.youtube.com/watch?v=GvXhJpY7k0g
has apparently 1500 lm

Also, I have no Idea what those letters mean. I know what a driver does, somewhat, a bit, but not much else.

[Anonymous No.1086523]

>>1084826
Chip On Board LEDs are the usual high power LEDs you can use for applications like this. Often on a star shaped aluminium PCB so you can attach it to a heatsink well. For the PWM driver circuit, you're probably better of buying a suitable one, without etching your own PCB and using SMD components you won't get it small enough otherwise.