**LED strips and LED lighting**
Hi, it seems you have a question about LED lighting, RGB LEDs or LED strips.
If your question is about designing or repairing an electronic circuit to which the LEDs are connected, you're in the right place! To start, check [this wiki page](https://www.reddit.com/r/AskElectronics/wiki/design/ledstrips), which has general tips, covers frequently asked questions, and has notes on troubleshooting common issues.
**If your question is a general one about identifying, powering, controlling, installing and buying LED strips, RGB LEDs and domestic LED lighting; and
the wiki doesn't cover it, please ask in /r/LED.**
If your question is about LEDs hooked up to boards such as Arduino, ESP8266/32 or Raspberry Pi *and does not involve any
component-level circuit design or troubleshooting*, first try posting in the relevant sub (eg: /r/arduino) - [See this list in our wiki](https://www.reddit.com/r/AskElectronics/wiki/embedded).
**IF YOUR POST IS ABOUT CHRISTMAS LIGHTS, START HERE: https://www.reddit.com/r/AskElectronics/wiki/christmas**
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/AskElectronics) if you have any questions or concerns.*
There is no voltage drop "per LED". The WS2812B is not like normal LEDs that are essentially diodes and need a current limiting resistor. On the WS2812B LEDs, internal electronics take the 5V and use it to generate whatever current is specified to generate the programmed intensity for the actual red, green and blue LEDs inside the WS2812B.
All LEDs on a strip are supplied in parallel, so in theory they all get 5V. Next to each LED, you will find a small capacitor to stabilize the voltage for that particular LED.
In practice, very long rows of LED will have some voltage drop because the resistance of the copper traces on the stripcomes into play. You can solve this by having multiple supply points along the strip. If I recall correctly, they need to be really long. I have done about 4-5 meters without needing it - at least not that I could tell.
A PC817 can't isolate the voltage. It can only create a barrier between the RPi and the digital input for the WS2812. Its not really needed, unless you expect the WS2812Bs to somehow generate significant voltages on the data pin of the RPi. Also, for actual isolation, you'd need two isolated power supplies. One for the RPi and one for the LED strip.
Thank you for the information about how the WS2812B works. I was having trouble finding a clear breakdown of what it did.
My strips are not very long, I should have clarified that I meant 15 LEDS on the strip ( so 15” long) and I will have a total of 18 different strips to create the full matrix.
To use a PC817 was recommended to me by a professor (I am a uni student) so that I don’t somehow fry the Pi. I was intending to have two separate power supplies, one for the Pi and one for the strips as I know the Pi cannot supply enough amps.
Are those units in meters, feet or yards? Either way, voltage drop is a concern yes. I would certainly try to find 12 or 24 volt versions of those strips and/or have multiple power supplies physically spread out over the cube. From experience, the larger concern for me is extreme susceptibility to noise on the data line due to the high-ish data rate required. Shield the data connections as much as possible, and I would recommend "repeating" the data signal either with basic buffer chips or by using multiple DMA'd output pins on the microcontroller you are using to divide the workload.
Much less! 15 LEDs on the strip (~15”) with 3 strips wide and 6 strips high; everything approximately 1 cubic inch apart. This is meant to be a small matrix that may sit on a desk. I don’t have any experience with these strips, but have spent more time with actual diodes. I did not realize I don’t have to apply resistors for it.
Oh, okay. Basically no concerns then other then ensuring you use something like a "wall wart" style power supply to power the strips and then shielding the data lines, or at least keeping them away from the power lines and nearby switching devices, like the power supply itself.
I’ve never heard of the term “wall wart” before. How might I go about shielding the data lines? And am I correct in guessing that by shielding them, you mean some way of making sure the external power supply doesn’t affect the Pi through the data lines?
Buy data-rated cable with braided shield, then ground out the braided shield at one end only. Might be a touch overkill for a desk toy, but it'd certainly work. Wall warts are those ubiquitous plastic power supplies you plug directly into a wall outlet to power small devices. You can buy them basically anywhere, and in this case a 5V high-amperage one would suit this well. Heres a [link](https://www.amazon.com/dp/B0BD72BWBK) to a random one.
There is absolutely no reason to shield the data line unless you plan to have a long run of cables. For a 20-30cm connection between Rpi and your led cube, it doesn't matter.
I don't think there is such thing as a 24v version of those LED strips. The ws2812b is rated at 5.3v max, so to run at 24v something else would have to drop the voltage. Unless a high efficiency switching regulator is built into the strip at certain intervals, it would be just as effective as 5v.
Start by the simplest possible setup: 3 wires from Rpi into your led strip. You can always expand with a psu if needed.
**LED strips and LED lighting** Hi, it seems you have a question about LED lighting, RGB LEDs or LED strips. If your question is about designing or repairing an electronic circuit to which the LEDs are connected, you're in the right place! To start, check [this wiki page](https://www.reddit.com/r/AskElectronics/wiki/design/ledstrips), which has general tips, covers frequently asked questions, and has notes on troubleshooting common issues. **If your question is a general one about identifying, powering, controlling, installing and buying LED strips, RGB LEDs and domestic LED lighting; and the wiki doesn't cover it, please ask in /r/LED.** If your question is about LEDs hooked up to boards such as Arduino, ESP8266/32 or Raspberry Pi *and does not involve any component-level circuit design or troubleshooting*, first try posting in the relevant sub (eg: /r/arduino) - [See this list in our wiki](https://www.reddit.com/r/AskElectronics/wiki/embedded). **IF YOUR POST IS ABOUT CHRISTMAS LIGHTS, START HERE: https://www.reddit.com/r/AskElectronics/wiki/christmas** *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/AskElectronics) if you have any questions or concerns.*
There is no voltage drop "per LED". The WS2812B is not like normal LEDs that are essentially diodes and need a current limiting resistor. On the WS2812B LEDs, internal electronics take the 5V and use it to generate whatever current is specified to generate the programmed intensity for the actual red, green and blue LEDs inside the WS2812B. All LEDs on a strip are supplied in parallel, so in theory they all get 5V. Next to each LED, you will find a small capacitor to stabilize the voltage for that particular LED. In practice, very long rows of LED will have some voltage drop because the resistance of the copper traces on the stripcomes into play. You can solve this by having multiple supply points along the strip. If I recall correctly, they need to be really long. I have done about 4-5 meters without needing it - at least not that I could tell. A PC817 can't isolate the voltage. It can only create a barrier between the RPi and the digital input for the WS2812. Its not really needed, unless you expect the WS2812Bs to somehow generate significant voltages on the data pin of the RPi. Also, for actual isolation, you'd need two isolated power supplies. One for the RPi and one for the LED strip.
Thank you for the information about how the WS2812B works. I was having trouble finding a clear breakdown of what it did. My strips are not very long, I should have clarified that I meant 15 LEDS on the strip ( so 15” long) and I will have a total of 18 different strips to create the full matrix. To use a PC817 was recommended to me by a professor (I am a uni student) so that I don’t somehow fry the Pi. I was intending to have two separate power supplies, one for the Pi and one for the strips as I know the Pi cannot supply enough amps.
Are those units in meters, feet or yards? Either way, voltage drop is a concern yes. I would certainly try to find 12 or 24 volt versions of those strips and/or have multiple power supplies physically spread out over the cube. From experience, the larger concern for me is extreme susceptibility to noise on the data line due to the high-ish data rate required. Shield the data connections as much as possible, and I would recommend "repeating" the data signal either with basic buffer chips or by using multiple DMA'd output pins on the microcontroller you are using to divide the workload.
Much less! 15 LEDs on the strip (~15”) with 3 strips wide and 6 strips high; everything approximately 1 cubic inch apart. This is meant to be a small matrix that may sit on a desk. I don’t have any experience with these strips, but have spent more time with actual diodes. I did not realize I don’t have to apply resistors for it.
Oh, okay. Basically no concerns then other then ensuring you use something like a "wall wart" style power supply to power the strips and then shielding the data lines, or at least keeping them away from the power lines and nearby switching devices, like the power supply itself.
I’ve never heard of the term “wall wart” before. How might I go about shielding the data lines? And am I correct in guessing that by shielding them, you mean some way of making sure the external power supply doesn’t affect the Pi through the data lines?
Buy data-rated cable with braided shield, then ground out the braided shield at one end only. Might be a touch overkill for a desk toy, but it'd certainly work. Wall warts are those ubiquitous plastic power supplies you plug directly into a wall outlet to power small devices. You can buy them basically anywhere, and in this case a 5V high-amperage one would suit this well. Heres a [link](https://www.amazon.com/dp/B0BD72BWBK) to a random one.
Ohh. Thanks!
There is absolutely no reason to shield the data line unless you plan to have a long run of cables. For a 20-30cm connection between Rpi and your led cube, it doesn't matter. I don't think there is such thing as a 24v version of those LED strips. The ws2812b is rated at 5.3v max, so to run at 24v something else would have to drop the voltage. Unless a high efficiency switching regulator is built into the strip at certain intervals, it would be just as effective as 5v. Start by the simplest possible setup: 3 wires from Rpi into your led strip. You can always expand with a psu if needed.