Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 4 of 4

Thread: Assistance with Teensy 3.6, WS2812B 144 LEDs/m Strips

  1. #1
    Junior Member
    Join Date
    Dec 2018
    Posts
    6

    Help with Teensy 3.6, WS2812B 144 LEDs/m Strips (Will Compensate for Assistance)

    Hey everyone,

    I am a completely new user to the field of electronic engineering and all that is involved with it. As someone who has only been a programmer for the most part of my life, I found that this area is of my interest to somewhat try to put together complex coding and use of electronics to be put together to make cool and interesting projects. I am eager to learn and am just looking for guidance and assistance with paths of thinking to help me look for the answers I need.

    I am currently interested in creating a project that is related to this project... https://www.pjrc.com/dodecahedron-wi...inity-mirrors/ as it is something I find very fascinating, portable (apparently it runs on batteries), and can be brought to shows that I go to.

    The materials that I currently possess:
    (1) Teensy 3.6 board with pins (and no Octo2812 adapter... should I get one?)
    (2) 1 meter of WS2812B 144 LEDs/m strip for prototyping and learning but planning for this project to use up to 5 meters
    (3) ELEGOO Upgraded Electronics Fun Kit w/Power Supply Module, Jumper Wire, Precision Potentiometer (Amazon: https://www.amazon.com/gp/product/B01ERPEMAC)
    (4) MP1584EN DC-DC Adjustable Power Step-down Voltage Regulator (10pcs) with 3A MAXIMUM output current

    Materials I am still considering:
    (1) A lithium polymer battery that is safe for consumers and a newbie like me to use. I understand very well the risks that entails at mishandling and awful care-taking of lithium batteries so I will do considerable amount of research in order to make sure I understand how to use this to power my project and learn more about what I can do to ensure when utilizing it to power my stuff, to have some sort of system to regulate when to cut off power when voltage is low.
    (2) A plug-in AC->DC power supply that is beefy enough to provide a great amount of power to this project.


    What I understand so far:
    (1) I am planning for the worst-case scenario for this project in which is primarily all within the power consumption of this project. From my understanding, a typical pixel can draw up to 20mA of power. With the WS2812B 144 LEDs/m strip, with 3 pixels results in a 60mA consumption. With 60mA of power consumption per pixel on a 144 LEDs/m strip, that is approximately (60mA*144 LEDs)/1000 = ~9A. That is a lot of power for one strip and I would be using up to 5 meters so that's ~45A.

    This is my one and only issue with this project. As someone who has NO experience in electrical work, to plan for such an awfully high amount of power consumption for this project that I want to make portable to last at least 8 hours (realistically speaking, with the use of more than just 1 battery supply because I HIGHLY doubt one battery can last this long). I would like to also mention that I will be cutting up the strips to only contain approximately 20 LEDs per strip into about 30 strips. Would this make a difference? Is there a way to wire these up separately to reduce such a huge power consumption? Would using a large capacity and voltage power supply help reduce such an intolerable amount of current draw? I would like to also ask that if the only way would be implementing a hard code in my sketch to reduce the maximum brightness and only limiting flashing max brightness but the others would be randomized patterns, would this reduce the stress enough? What other solutions may there be?

    I also realize the problem with idle current draw from the LEDs from the batteries from the research I have done and I believe I could simply use power transistors or SCR to ensure that there is no current being drawn when the device is in idle. Is this effective or would using a on/off switch be a better solution?

    Another thing is the issue with safety amongst using lithium polymer batteries, it can be explosive if too much heat is ongoing and with such a power hungry project, I find this so difficult to cope and figure a solution. Although I can use other alternatives since weight is not a problem with me but size would be. I would to encase it to be attached to my totem so that it can be passed event security because if it looks suspicious, I would be unable to bring in my awesome totem that I would spend multitude of hours working on and coding. So in short, lithium polymer would work easily. I am unsure of what would be the best case of doing so that will comply with TSA/FAA rules when traveling to out-of-state concerts, maybe I could ship but that's a totally different subject.

    I appreciate whoever is reading this and hope to gain some knowledge and assistance! If someone is willing to work personally with me in return compensated for it (not sure if this is against the forum rules but let me know and I'll remove this part).
    Last edited by Jvyy; 12-14-2018 at 05:15 PM.

  2. #2
    Senior Member
    Join Date
    Jan 2013
    Posts
    180
    I won't be able to help you with the high power requirements but I can off a few tidbits of advice from being a longtime forum reader and having built a few smaller Addressable RGB LED projects. Eventually the "big guns" will chime in and offer advice about power management....

    Quote Originally Posted by Jvyy View Post
    I am eager to learn and am just looking for guidance and assistance with paths of thinking to help me look for the answers I need.
    You've come to the right place.

    Quote Originally Posted by Jvyy View Post
    (1) I am planning for the worst-case scenario for this project in which is primarily all within the power consumption of this project. From my understanding, a typical pixel can draw up to 20mA of power. With the WS2812B 144 LEDs/m strip, with 3 pixels results in a 60mA consumption. With 60mA of power consumption per pixel on a 144 LEDs/m strip, that is approximately (60mA*144 LEDs)/1000 = ~9A. That is a lot of power for one strip and I would be using up to 5 meters so that's ~45A.
    Your math is correct. In reality, the current might be less than this maximum. However, with 1296 pixels requires careful design. Managing this much current will likely be your biggest challenge. See Pauls article about using the OctoWS2811 library but also contains much more general info about building "large" LED displays – especially the section about "LED Power Requirements".


    Quote Originally Posted by Jvyy View Post
    portable to last at least 8 hours
    Using this battery?

    Ok, joking. But, 1296 pixels for 8 hours seem EXTREMELY CHALLENGING. What batteries have you considered?

    Quote Originally Posted by Jvyy View Post
    use power transistors or SCR to ensure that there is no current being drawn when the device is in idle. Is this effective or would using a on/off switch be a better solution?
    See Paul's article linked to above; search for "WS2811 Idle Power". Yes, an on/off switch would work as well. "Better" is subjective, depending upon your requirements.

    Quote Originally Posted by Jvyy View Post
    safety amongst using lithium polymer batteries, it can be explosive...
    Well, don't exceed the current rating of the battery (or batteries). Consider if multiple batteries can be used to power individual smaller parts of the larger display. Note, the batteries would share a common ground, but not the + side.

    On this subject, have you considered one of these or something similar?

    Do you intend for the Teensy to internally generate the pixel data to be displayed or will that come from someplace else and then sent to the Teensy (For example: DMX, Artnet, other protocols, etc)?

    General advice:

    1) Start smaller, learn, then do a larger project. For example, a matrix of 12 x 12 pixel only needs about 2 amps @5v but it starts to touch on some of the issues you'll run into in larger displays. You'll learn alot and be better prepared to make the next step up.

    2) Consider using Teensy 3.2. I believe using it with OctoWS2811 Adaptor for Teensy 3.2 board sold by PJRC will support all your pixels, plus it's smaller, and less expensive.

    3) Buy spares of all but your most expensive components. For example, get an extra Teensy. At some point it is common to wonder "have I damage the Teensy, is there a bad solder joint, etc. Having another known good component will give you something to compare against and also give you a backup if a component gets damaged. Paul advises (paraphrasing) "get spare pixels, some will be bad".




    I appreciate whoever is reading this and hope to gain some knowledge and assistance! If someone is willing to work personally with me in return compensated for it (not sure if this is against the forum rules but let me know and I'll remove this part).[/QUOTE]

  3. #3
    Junior Member
    Join Date
    Dec 2018
    Posts
    6
    Quote Originally Posted by markonian View Post
    I won't be able to help you with the high power requirements but I can off a few tidbits of advice from being a longtime forum reader and having built a few smaller Addressable RGB LED projects. Eventually the "big guns" will chime in and offer advice about power management....

    You've come to the right place.

    Your math is correct. In reality, the current might be less than this maximum. However, with 1296 pixels requires careful design. Managing this much current will likely be your biggest challenge. See Pauls article about using the OctoWS2811 library but also contains much more general info about building "large" LED displays – especially the section about "LED Power Requirements".

    Using this battery?

    Ok, joking. But, 1296 pixels for 8 hours seem EXTREMELY CHALLENGING. What batteries have you considered?


    See Paul's article linked to above; search for "WS2811 Idle Power". Yes, an on/off switch would work as well. "Better" is subjective, depending upon your requirements.

    Well, don't exceed the current rating of the battery (or batteries). Consider if multiple batteries can be used to power individual smaller parts of the larger display. Note, the batteries would share a common ground, but not the + side.

    On this subject, have you considered one of these or something similar?

    Do you intend for the Teensy to internally generate the pixel data to be displayed or will that come from someplace else and then sent to the Teensy (For example: DMX, Artnet, other protocols, etc)?

    General advice:

    1) Start smaller, learn, then do a larger project. For example, a matrix of 12 x 12 pixel only needs about 2 amps @5v but it starts to touch on some of the issues you'll run into in larger displays. You'll learn alot and be better prepared to make the next step up.

    2) Consider using Teensy 3.2. I believe using it with OctoWS2811 Adaptor for Teensy 3.2 board sold by PJRC will support all your pixels, plus it's smaller, and less expensive.

    3) Buy spares of all but your most expensive components. For example, get an extra Teensy. At some point it is common to wonder "have I damage the Teensy, is there a bad solder joint, etc. Having another known good component will give you something to compare against and also give you a backup if a component gets damaged. Paul advises (paraphrasing) "get spare pixels, some will be bad".
    [/QUOTE]

    I appreciate your response and I hope to continue to learn more about what I can do about this issue of large current flow in this particular project. And honestly this is a considerable amount of stress for me since it's the only issue I am having in this project. Also how to regulate the battery to prevent anything that would cause the battery to explode or catch on fire. It's scary to be dealing with lithium polymer batteries. Are there possibly other suggestions that are allowed to be brought in or possibly even portable charging banks instead? I can honestly buy like three battery banks if anything and have it wired up in 6 so that each battery can power up to 5 strips each?

    I intend to generate pixel data through only Teensy. Also, I believe the OctoWS2811 can be used on a Teensy 3.6 (which I have) by using additional headers to connect the two together. So if anything, I could possibly do that or find another alternative. Also, do you think this DC-DC converter could be used to deal with the current problem?

    Link: https://www.digikey.com/product-deta...357-ND/4941280

    It can output 5V up to 150W which is a lot and I could possibly do additional work to deal with the excessive heat and everything into my design too. Not too sure. I will indeed start small and work my way up as I gain more experience, just need assistance if anything as to what I should be learning besides the basics of soldering and whatnot but more complex things that I probably am not thinking about.

    I'll also consider getting spare parts after the holidays too since that is indeed something I should consider since I am still new.

  4. #4
    Senior Member
    Join Date
    Jan 2013
    Posts
    180
    Some additional thoughts....

    1) You've said that you are new to electronics. Consider taking a course in Basic Electronics. This could be from a local community college (depth and detail but costly in time and money but well worth it if pursuing a career in electronics. Or an online course such as ones offed by Udemy (for example) which are more appropriate for a hobbyist (low cost and time commitment, less depth).

    For example, here are several Basic Electronics courses from Udemy. Be aware that Udemy has deeply discounted sale prices nearly all the time. I suggest, pick a course you want, sign up for a Udemy account, and look for them to offer your chosen course for < $20. If you're overwhelmed by too many choices, perhaps consider Tech Explorations™ Basic electronics for Arduino Makers.

    I am no affiliated with Udemy only use them as an example of what's available.

    I suspect that you know more that you admit to. But a little more formal training would go a long ways toward lowering your "stress level".

    2) It was Apollo 11 that landed the first humans on the Moon. Not Apollo 1.

    I'll reiterate my advice to start small and work up to your ultimate goal in a series of steps of increasing challenge. For example, make a project with 144 pixels. Take what you learn from that and make your next project with, say, 400 pixels. Then take what you learn from that, and make your ultimate project with 720 pixels.


    3) Prefer COTS (Commercial off-the-shelf ) components over bespoke solutions.

    I mention this with regard to batteries such as the ones from Jackery. I couldn't find this info specifically, but I expect these combine battery, regulator, current limiting, and over temperature protection into a single portable package.

    4) Teensy 3.2 has plenty of performance for all but the most demanding Addressable RGB LED projects, even more so if you use the OctoWS2811 LED Library. Nothing wrong with using a Teensy 3.5 or 3.6 but likely not required.

    The exception being if generated display patterns require high performance or [single-precision] floating point mathematical calculations. In that case, the higher performance, larger Flash and RAM size, and built-in [single-precision] floating point hardware might be useful or required.

    5) You've stated twice that LED power is your "one and only issue". I agree that this will be the most challenging. However, it's normal that there will be other issues and decisions to make and you'll have to learn and work through to your preferred solution.

    6) I watch the video you posted of the Dodecahedron with LEDs and Infinity Mirrors. That is super-cool, imo.

    Notice that only a small number of the total pixels are lit at the same time!!! My experience from my 12x12 pixel matrix and from what Paul has said about his video wall projects is that if all the pixels are at full brightness it can be blindingly bright. In fact, for my indoor non-party use, i normally set the LED/Pixel brightness to be in the 10 - 20 range out of 255. Otherwise, it was just too bright.

    However, given that "At low duty cycle the perceived increase in brightness is much bigger than at almost full duty cycle, where the increase in brightness is almost imperceivable."

    That means that if you use the lower range of duty cycle it can require far less current than the maximum and still be pretty bright. Whether this is acceptable or not will depend on the details of the patterns you generate, but you have control over this.

    Writing this has also made me realize that you almost certainly will want a master brightness control of some sort.


    Best regards. I look forward to following your progress. Please keep us informed.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •