Powering RGB LEDs with a battery

Thread Starter

Tostra

Joined Sep 15, 2018
26
Hi. I'm new here and rather bad at electronics. Now I'm about to start a guitar project and I want to have RGB LEDs inside of it, and I have a few questions. I will have 10 3W LEDs in the guitar to distribute the light properly, but they will most likely be turned down in brightness.

1) Does it make any difference which driver I choose except how the app looks? I don't want to buy cheap parts that don't work properly, but I also don't want to spend money where I don't have to.
2) Obviously I will need to power these with batteries. The standard in instruments is 9V, so that's what I first thought I was going to use, but I'm not sure that will work well enough. Does anyone know of a better power supply that doesn't take up much more room than a 9V battery?
3) These drivers are designed for LED strips. I'm actually not completely sure how I'm supposed to wire individual LEDs to them. My guess is the individual colors in series wired to the correct pin on the driver? In that case, I suppose the voltage from a 9V battery would actually be split over the three colors, giving them each 3V, right? Then they would actually work? But I guess a 9V battery wouldn't last long that way?
4) Do I need any resistors in this circuit?

These are the parts I'm considering:
I want to use these four pin LEDs:
https://www.ebay.com/itm/3X1W-3X3W-RGB-RGBW-Epiles-High-Power-LED-Diode-4pin-6pin-8pin-with-20mm-star/253497202109?hash=item3b059c55bd:m:mQD0I6wJtdJDMi1cnM5FOhw

And one of these two bluetooth drivers:
https://www.ebay.com/itm/5V-24V-IP65-Mini-Bluetooth4-0-LED-Wireless-Controller-for-RGB-LED-Strip-Light/253777197350?hash=item3b164cb926:m:m8GFbY3Qz3z48p_Jqcx4RDw
https://www.ebay.com/itm/SMD-5050-3528-2835-RGB-LED-Light-strip-DC12V-24key-44-IR-RF-Bluetooth-controller/253535396045?hash=item3b07e320cd:m:mtcfSda9Q7_L8zxw0-Yrbzw
 

Bernard

Joined Aug 7, 2008
5,479
Very rough figures: Operating all in series @ 100 mA = about 9 W or with 4 AA Alk. = about an hour.
@ 350 ma = 31 W, 5 A- not possible with 4 AAs
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
I'm sorry... Do you mean that if I run all 10 LEDs it won't run on 4 AAs? I wasn't going to use AAs but 9v. I realize it's only a bit more juice and running them at 350-1000mA as they're rated will be more than abattery can handle comfortably, but I'm not sure which part of my question you're responding to? I'm really not very good at this electronics stuff, so please teach me :)
 

dl324

Joined Mar 30, 2015
10,536
I wasn't going to use AAs but 9v.
9V transistor batteries don't have much "juice".

When you operate LEDs, you need to have a way to limit current. That means dissipating power as heat, not light.

More information = better suggestions.
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
Huh, I actually didn't know that. But alright, I can try to explain my situation a bit more. I've been spending the day drawing concepts, and this is a very rough sketch of the space I have available. The greenish area is hollow, and I would prefer not to have anything out there. The red areas are occupied by pickups, strings though the body and a few screws, so I would prefer not to have anything there, even though I might have a bit of extra room underneath the pickups.upload_2018-9-15_21-35-7.png

The space between the pickups is approximately 5,5*7,5*3 cm and the space beneath the bridge area is about 10*7,5*3cm.
I would prefer not to use up all of the room as it might get a bit cluttered, but this is pretty much where I'm at as far as electronics go. I know where it goes and what I would like to go there, but not how I'll make it work.
My plan was to make a cavity in both areas. between the pickups would be where the driver went and then I could have the 9V battery beneath the bridge with the rest of the electronics.
Now that I think about it though, would it be possible to fit a lot of AAs between the pickups? I don't know if heat is something I should be concerned about. There will be a strip of acrylic going down the center of the guitar all the way that I definitely don't want to overheat, and of course the bulk of the guitar will be made from wood, so I would like it to stay pretty cool. Again, maybe 9V batteries isn't great for this project.
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
Actually, I have a bonus question (sorry):
I wanted to let a three way toggle control whether the LEDs are on, off or reacting to what is played on the guitar. I would do that similar to how this is done, except I would wire it to the output jack instead of a microphone:
However this is a single color LED. Can it be "translated" easily into RGB? Can I simply wire three of them?
To be honest, I don't know how it works. I suppose it's a gate that opens when the output is above a certain level, but I don't know any more than that. I'm a bit concerned that wiring it like that will use up the current generated by the pickups and to the lighting right but I would get no or bad sound from the guitar. Does anybody know or should I post it as a seperate question with a better headline?
 

bertus

Joined Apr 5, 2008
20,465
Hello,

Here is some info on the 9 V PP3 battery.
It is VERY small in comparisson with a AA battery, as it consists of 6 AAAA batteries:

PP3_List of battery sizes - Wikipedia.png
I would suggest to have a larger battery outside the guitar.

Bertus
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
What if I can fit an 8AA pack in there? Will that be able to run it?
I'll have to measure things first, but I suppose I can make room, actually.
 

Bernard

Joined Aug 7, 2008
5,479
Do you really need 3W LEDs? Do you want more than one color on at a time?
I would try a few different LEDs @ different currents to see what is pleasing. For changing colors vs music, check color organs, there are some on AAC.
I just delivered a 24 in. throbbing spider with 40 white & 2 green LEDs . Total peak drain is 35 mA running on 3 AA alk. batteries. 8AAs could drive a boat load of LEDs.at a reasonable current.
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
To be honest, I think 30W LEDs is way overkill for this. However, I really have no way of testing it before I glue it together, so I would rather have too much than too little as I suppose I can just turn them down.
I was planning on installing 1W LEDs, but I can only find 3W and above. And then I need quite a few of them to spread the light properly.
The reason I want to have them very bright is because they're going to be mounted inside the guitar and make the whole thing glow through cracks in the top and back plates that I have filled with resin. The cracks aren't very wide, so I want to make sure they actually light up. I might even go in with a chisel before I flood it in resin to make them wider on the inside and catch more light.
This is the plan so far, I hope you see my idea. I really hope it's going to be as awesome as it is in my head, as it's a project I've been wanting to do for a while:
upload_2018-9-16_1-10-1.png

Also... I'm a cellist, not a guitarist. I kinda want a guitar that can put a show on by itself ;-P
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
But to return to my technical questions instead of going on about music as I tend to do:
Will I be able to run my overkill LED circuit on 4-8AAs going into the drivers linked above? Do I have to match my number of batteries to the voltage of the LEDs or will I simply be able to run them longer with more batteries? If so, can someone please explain me the wiring, as I'm not sure I have the right idea about how I'll need to do it.

Do people here know how to solve my sound sensitivity thing? It would be a really neat touch :)
 

dendad

Joined Feb 20, 2016
3,431
Go with addressable LEDs, like...
https://www.ebay.com.au/itm/WS2812B-5050-RGB-30-LED-1M-String-Strip-Lights-Individual-Addressable-G/351706858413?epid=1893859441&hash=item51e35cc3ad:g:oewAAOSw1DtXDemz
They are also available on wires...
https://www.ebay.com.au/itm/DC-5V-50PCS-WS2811-RGB-Full-Color-12mm-Pixels-digital-Addressable-LED-String-CU/152716603983?hash=item238e9e724f:m:maTq-QoYF4G9giMm2lxZgUw&var=452350148383

Then an Arduino Pro Mini (3.3V version)....
https://www.ebay.com.au/itm/1Pcs-Arduino-Compatible-Nano-Pro-Mini-ATMEGA328-3-3V-8M-Replace-ATMEGA128-New-ni/282907471690?epid=1882435341&hash=item41de996f4a

I have built a Hula Hoop with these in it.

The hoop is powered by a couple of LiPo batteries and a charge controller...
https://www.ebay.com.au/itm/Lipo-Lion-Battery-Charging-Module-with-Protector-TP4056-Arduino-Solar-Charger/132751370946?epid=10022856770&hash=item1ee8992ac2:g:Q~MAAOSw-tFbCvdX

The cells I use are 2 of these in parallel...
https://www.ebay.com.au/itm/4-x-ICR-18500-Lithium-Battery-1400mAh-3-7V-Li-ion-Rechargeable-Batteries-Cell/152604474619?hash=item2387ef7cfb:g:1xwAAOSw4shX32I8 but is you ahve the room, you can go to 18650 cells...

https://www.ebay.com.au/itm/Samsung-ICR18650-26F-26F-2600mAh-3-6V-Lithium-Li-Ion-Cell-Rechargeable-Battery/152942805469?hash=item239c1a01dd:m:mA34sJ7vzT_QttypszbXRNg&var=452710936814

To program the Arduino, a USB serial lead is needed too, but if you have the room, an Arduino with built in USB is better.
With the above setup, eack LED is controllable for colour and brightness, so it can be animated, even under control of the music.
At least have a look at this sort of thing.

All these links are just examples I found. Parts are available from many sources.


Have a look at this video...
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
Thank you dendad. That really would be perfect, but the thing is I want to have individual LEDs mounted in a way so I can pull them out through the pickup cavities and replace them if they should die one day. Also, I don't think a strip will be strong enough for this.
 

dendad

Joined Feb 20, 2016
3,431
Thank you dendad. That really would be perfect, but the thing is I want to have individual LEDs mounted in a way so I can pull them out through the pickup cavities and replace them if they should die one day. Also, I don't think a strip will be strong enough for this.
Use the wired version. Just make sure you note the connections if you need to change them.
At least have a play with some to see how they go.
Putting an Arduino there will allow you to have active control, or if you were to use an ESP8266 board, remote control via WiFi, or ESP32 for WiFi and BlueTooth.
Lots of fun :)
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
Yeah, but they're still only 0.3W where I was looking for >1W diodes. Also, I've only ever done very little arduino stuff, I would prefer to stick to a battery and a wire to be honest ;-)
However I realize that with arduino I would be able to make my system much more efficient and have better control over for instance sound sensitivity. I just want it done in a simpler way really, and since I can do the job with an off the shelf driver, I think that's the way for me.
If you can convince me why it's better for me and show me that it can be done simply and relatively cheaply, I will consider an arduino system instead of a driver, but I'm not fond of it.
 

dendad

Joined Feb 20, 2016
3,431
Do you just want LEDs to be on, or to change?
That is what you need to decide. If you want to control LEDs, an Arduino or similar is the way to go. Otherwise, you can get away with a battery, current limiting resistor and LED.
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
I want light, that's the main thing. I could settle for a combination of white and blue LEDs, but I would rather install RGBs so I have the possibility to change color. Do you mean it's not possible to have RGBs on a battery? Why is it any different than single colors?
Again, I realize that an arduino would control the colors better, and I certainly will follow the tutorials you sent me for another project as I think it's really cool, but here my main focus is the effect bright lights could have on stage.
 

dendad

Joined Feb 20, 2016
3,431
You can run RGB LEDs from a battery, just have 3 current setting resistors, on for each colour.
Don't have a 9V battery if you are just running 1 LED as it is too lossey. 3V or 4.5V battery will be better.
RGB LEDs cannot be series connected as they have a common connection (usually) so separate Red, Green and Blue LEDs are needed and that may defeat what you want to do, to get different colours. The addressable LEDs are pretty bright, so I would suggest you get some and have a play to see if it is ok.
Have you played with Arduinos and PWM to change the LED colours? Try building up something first to finalize what you actually want.
LiPo batteries may be better as they have a greater power density over dry cells.
Figure out how many LEDs you need, and the Brightness. Then what control you want. There are many ways to go so it is a bit hard to advise at the moment. I just know I would use Arduinos and WS2812 (or similar) to do it. That way it is very easy to change, either manually or under some control system.
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
From the sellers in the links put in my first post I can buy 6 pin LEDs, so if wiring the colors in series is what I need to do for color control, I can buy those. Can you draw me a quick drawing, just in paint or something, to show me how you would wire a circuit containing multiple LEDs, an LED strip driver with four pins and a battery case? I think it should be done like this, but I'm not sure where the resistors should go?
upload_2018-9-16_10-31-24.png
 

Thread Starter

Tostra

Joined Sep 15, 2018
26
I suppose I should just figure out how an LED strip is wired internally and do the same thing in the guitar? From what I can see they're pretty much wired like I did up there, except they have a 130 ohm resistor after each color. Why is that? Should I make sure to arrange them in sections of three or can I have one long chain of 10?
 
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