How to connect LED lights for an art project

Thread Starter

JaredSD

Joined Apr 3, 2017
22
Hello community. I am brand new here, and would love your feedback/help with my project. I am creating a new piece of canvas artwork and will be embedding LED lights into it. You can see the start of the project in the picture. Each small square within the circle will get an LED, and other areas (TBD) will probably get them as well. I have also included a spec chart of the LEDs. I am using diffused orange, red, and yellow.

My question(s) are regarding how to properly hook them up. I will list out the questions/thoughts/assumptions below so it is easier to read.

1. I am not sure how many of these I am going to end up using. Based on the chart provided though, how can I go about the math for figuring this out? Let's say I end up using 30 lights in total.
2. How would you power this? Would you use one of those portable battery packs? Something that plugs into the wall? If possible I would like to use something that does not plug into the wall. I am open to suggestions on products for this. If you do have recs, please provide any links or places to get the products.
3. If I use this many lights, I would imagine wiring them in parallel is best? How does this affect the math? Also, what if the lights are spaced about by 2 feet? What kind of "connector" wire do I need to use? Is there a preferred gauge or thickness oIoTf wire? In addition, if the current is traveling further does this affect the math?
4. Lastly....would you connect certain areas together first in parallel and then have them meet together closer to the source? For example, let's say I did 3 circles with 10 lights each. Would I do the three circles by themselves and then have them meet together?

I apologize if this seems all over the place. I am trying to describe this the best I can and I am not the best at it. However, I can easily grasp what you all shoot back to me. Let me know if there is any information missing. I suppose the biggest mysteries to me is the math in general when wired parallel, connecting multiple areas together, and finally how to power this thing up. Ultimately it will be entered in an art show and no wires going to an outlet would be best if possible, and also a solution to where these would be powered up for quite a while. Thank you so much for any time you may have for me. It means the world.

Jared
 

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Reloadron

Joined Jan 15, 2015
4,508
Very good on providing the data sheet. In an effort to keep this simple a LED is a current driven device, if you look at your data sheet you will see an Ifwd = 20 mA (.020 Amp) that is the Forward Current. The IF is the same for all of the LEDs on your sheet. Next you will see a Forward Voltage that changes based on the LED and yours are 2 and 3 Volts depending on LED.

Next you have the configuration as you mentioned. Parallel, Series or Both. Each LED should have the current through it limited so in keeping things simple we place a resistor in series with the LED. Things will look a little like this. Vsupply or Supply Voltage - Vfwd of LED / Ifwd. Example would be if I have a 5 Volt Supply and my LED Vfwd is 2 Volts and Ifwd is .020 Amp I get 5 - 2 / .020 = 3/.020 = 150 Ohm resistor. This will limit your LED current to 20 mA. Now if I placed 30 LEDs in parallel, each with a series resistor my total current would be 30 * .020 = 0.6 Amp so you could likely get by using a 5 Volt supply rated at 1 Amp. The 150 Ohm is a common resistance value so for an off the shelf resistor a 150 1/4 watt would be fine. Using a Vfwd of 3 Volts we get 5 - 3 = 2 / .020 = 100 Ohms but 100 Ohms is not common so we coould bump it up to 120 Ohms.

I would place a resistor on each LED and place the resistors on one leg of the LED and run a little heat shrink tubing to insulate the LED legs with the resistors. The resistor can be placed in either leg but I would make them all the same. Using a resistor for each LED is just one way to go about it and what we have here is just a single example. There are other ways to go about it.

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
Very good on providing the data sheet. In an effort to keep this simple a LED is a current driven device, if you look at your data sheet you will see an Ifwd = 20 mA (.020 Amp) that is the Forward Current. The IF is the same for all of the LEDs on your sheet. Next you will see a Forward Voltage that changes based on the LED and yours are 2 and 3 Volts depending on LED.

Next you have the configuration as you mentioned. Parallel, Series or Both. Each LED should have the current through it limited so in keeping things simple we place a resistor in series with the LED. Things will look a little like this. Vsupply or Supply Voltage - Vfwd of LED / Ifwd. Example would be if I have a 5 Volt Supply and my LED Vfwd is 2 Volts and Ifwd is .020 Amp I get 5 - 2 / .020 = 3/.020 = 150 Ohm resistor. This will limit your LED current to 20 mA. Now if I placed 30 LEDs in parallel, each with a series resistor my total current would be 30 * .020 = 0.6 Amp so you could likely get by using a 5 Volt supply rated at 1 Amp. The 150 Ohm is a common resistance value so for an off the shelf resistor a 150 1/4 watt would be fine. Using a Vfwd of 3 Volts we get 5 - 3 = 2 / .020 = 100 Ohms but 100 Ohms is not common so we coould bump it up to 120 Ohms.

I would place a resistor on each LED and place the resistors on one leg of the LED and run a little heat shrink tubing to insulate the LED legs with the resistors. The resistor can be placed in either leg but I would make them all the same. Using a resistor for each LED is just one way to go about it and what we have here is just a single example. There are other ways to go about it.

Ron
Thanks so much for the info! From this I have a couple follow up questions.

Where I get these heat sink things you are talking about?

Also, what would you suggest as for powering them? Is there something I could use which could be tucked behind the painting, and still be strong enough to power them for quite some time?
 

absf

Joined Dec 29, 2010
1,942
It is "heat shrink tubing" not "heat sink". Two different things. You can get heat shrinks almost every where eBay, Amazon, DigiKey, Daiso, and even Radio Shack.


Here is a video how to use them.

Allen
 

Reloadron

Joined Jan 15, 2015
4,508
Where I get these heat sink things you are talking about?
Heat sink things? You do not need any heat sink materials. You just need some series resistors which any electronic supply house should have. Digi Key and Mouser to name a few or even Amazon has resistors. The power supply is another Amazon item or any parts house. Thank you to absf for the clarification as to heat shrink versus heat sink. :)

Using the 5 Volt wall wart you would just cut off their plug and hard wire it to the LEDs observing correct polarity.

Ron
 

Reloadron

Joined Jan 15, 2015
4,508
I made a small basic cartoon of what you can do. Sorry I don't really have any pictorial software so you get a very basic electrical schematic.

LED Example.png

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
It is "heat shrink tubing" not "heat sink". Two different things. You can get heat shrinks almost every where eBay, Amazon, DigiKey, Daiso, and even Radio Shack.


Here is a video how to use them.

Allen
Thanks buddy. I read that wrong on mobile. See what a strong beer does haha?

Still looking for power source suggestions. Thanks for all the help so far!
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
Heat sink things? You do not need any heat sink materials. You just need some series resistors which any electronic supply house should have. Digi Key and Mouser to name a few or even Amazon has resistors. The power supply is another Amazon item or any parts house. Thank you to absf for the clarification as to heat shrink versus heat sink. :)

Using the 5 Volt wall wart you would just cut off their plug and hard wire it to the LEDs observing correct polarity.

Ron
Thanks! I just saw this. Yes, I read your post wrong earlier. Thanks much for the clarification guys haha.

Thanks for the suggestion on the power supply. I feel that plugging it in might have to happen. However, is there a way to do it via not plugging it in? Would a 5-volt battery work or something else? It would be the best option, but I will settle for what has to work.
 

Reloadron

Joined Jan 15, 2015
4,508
Thanks! I just saw this. Yes, I read your post wrong earlier. Thanks much for the clarification guys haha.

Thanks for the suggestion on the power supply. I feel that plugging it in might have to happen. However, is there a way to do it via not plugging it in? Would a 5-volt battery work or something else? It would be the best option, but I will settle for what has to work.
I doubt you will find a 5 Volt battery. Would a battery work? Absolutely a battery can be used. The problem is choosing a suitable battery which will have a long life and yet not be a monster. Rechargible batteries come in several chemistry and voltages. Once the LEDs are configured it becomes a matter of total current and what a battery can deliver for how long.

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
I doubt you will find a 5 Volt battery. Would a battery work? Absolutely a battery can be used. The problem is choosing a suitable battery which will have a long life and yet not be a monster. Rechargible batteries come in several chemistry and voltages. Once the LEDs are configured it becomes a matter of total current and what a battery can deliver for how long.

Ron
Got it. That will be the last step I suppose. Thanks for the help on this thread!
 

dl324

Joined Mar 30, 2015
8,913
Got it. That will be the last step I suppose. Thanks for the help on this thread!
Actually, it's the first step.

A 9V NiMH battery might be convenient if you don't require long run time, and it's rechargeable. The voltage is high enough that you could put two LEDs in series with each current limit resistor; maybe three, depending on forward voltage. Then wire up as many parallel strings as you need.
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
Actually, it's the first step.

A 9V NiMH battery might be convenient if you don't require long run time, and it's rechargeable. The voltage is high enough that you could put two LEDs in series with each current limit resistor; maybe three, depending on forward voltage. Then wire up as many parallel strings as you need.
Unfortunately it does require long run time. I think the venue is open about 12 hours a day, and the show lasts for 19 days. Might not be practical, even though it would be best.

I suppose there is not much harm if I had to keep them plugged in at all times. LEDs are known to not get hot and can handle the constant current I believe.
 

Reloadron

Joined Jan 15, 2015
4,508
While the battery approach is nice things work a little like this. Using a typical 9 Volt battery you could reduce the current drain on the supply (battery). Initially we used 30 LEDs * .020 Amp = 600 mA (0.6 Amp). OK, if we increase the voltage and half the current the current drain would drop to let;s say 300 mA (0.3 Amp).The nine-volt battery, or 9-volt battery, in its most common form was introduced for the early transistor radios. It has a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in walkie talkies, clocks and smoke detectors. Among several part numbers it is known as a PP3 Battery in most circles. They come in several flavors with the following current ratings:

Alkaline 550 mAh
Zinc–carbon 400 mAh
Lithium 1200 mAh

You might get an hour on standard zinc carbon, maybe close to two hours with Alkaline and maybe close to four hours using a Lithium and this is all give or take on a disposable 9 volt battery.

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
While the battery approach is nice things work a little like this. Using a typical 9 Volt battery you could reduce the current drain on the supply (battery). Initially we used 30 LEDs * .020 Amp = 600 mA (0.6 Amp). OK, if we increase the voltage and half the current the current drain would drop to let;s say 300 mA (0.3 Amp).The nine-volt battery, or 9-volt battery, in its most common form was introduced for the early transistor radios. It has a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in walkie talkies, clocks and smoke detectors. Among several part numbers it is known as a PP3 Battery in most circles. They come in several flavors with the following current ratings:

Alkaline 550 mAh
Zinc–carbon 400 mAh
Lithium 1200 mAh

You might get an hour on standard zinc carbon, maybe close to two hours with Alkaline and maybe close to four hours using a Lithium and this is all give or take on a disposable 9 volt battery.

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
That certainly tells me a lot, thanks. I don't have the time to be there every 4 hours to switch out batteries. Even if I was somehow able to rig up a 20,000 mAh battery battery pack to it I would have to go every other day to switch it out with a fully charged one. It could work perhaps?
 

Reloadron

Joined Jan 15, 2015
4,508
That certainly tells me a lot, thanks. I don't have the time to be there every 4 hours to switch out batteries. Even if I was somehow able to rig up a 20,000 mAh battery battery pack to it I would have to go every other day to switch it out with a fully charged one. It could work perhaps?
The main problem with using a battery is depending on circuit configuration the battery or battery pack starts to grow in size so eventually you can end up with a large battery. Using a small wall wart power supply, as I linked to leaves you the option of trying to hide just a single small wire. Artistic camouflage? :)
You can try a battery if you like and see how it works out.

Ron
 

Thread Starter

JaredSD

Joined Apr 3, 2017
22
Very good on providing the data sheet. In an effort to keep this simple a LED is a current driven device, if you look at your data sheet you will see an Ifwd = 20 mA (.020 Amp) that is the Forward Current. The IF is the same for all of the LEDs on your sheet. Next you will see a Forward Voltage that changes based on the LED and yours are 2 and 3 Volts depending on LED.

Next you have the configuration as you mentioned. Parallel, Series or Both. Each LED should have the current through it limited so in keeping things simple we place a resistor in series with the LED. Things will look a little like this. Vsupply or Supply Voltage - Vfwd of LED / Ifwd. Example would be if I have a 5 Volt Supply and my LED Vfwd is 2 Volts and Ifwd is .020 Amp I get 5 - 2 / .020 = 3/.020 = 150 Ohm resistor. This will limit your LED current to 20 mA. Now if I placed 30 LEDs in parallel, each with a series resistor my total current would be 30 * .020 = 0.6 Amp so you could likely get by using a 5 Volt supply rated at 1 Amp. The 150 Ohm is a common resistance value so for an off the shelf resistor a 150 1/4 watt would be fine. Using a Vfwd of 3 Volts we get 5 - 3 = 2 / .020 = 100 Ohms but 100 Ohms is not common so we coould bump it up to 120 Ohms.

I would place a resistor on each LED and place the resistors on one leg of the LED and run a little heat shrink tubing to insulate the LED legs with the resistors. The resistor can be placed in either leg but I would make them all the same. Using a resistor for each LED is just one way to go about it and what we have here is just a single example. There are other ways to go about it.

Ron
Any idea what size heat shrink tubing to use for this? I am looking on ebay.
 

Reloadron

Joined Jan 15, 2015
4,508
Small, about a 1/8" or 1/4" ID before shrink. That will allow slipping over the resistor and LED Leg.

Ron
 
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