Hello my friends,
I am making a project for a working miniature of the Las Vegas sphere and I was hoping if you could help me with the project. My idea is to connect a led strip to an Arduino Uno r3 and control the sphere from my phone. My goal is make the sphere project different animations similar to the Las Vegas sphere.
Let me know if you need further information and if you have any ideas for how can I do this.
Thank you!
What is the diameter of the sphere ?
How many LEDs do you anticipate using to cover the sphere ?
How will lay out the LEDs so that they cover the globe evenly to allow you to show images on them ?
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Learn how to program that strip to do what you want and the rest will be simple.
Take a look at this https://www.youtube.com/watch?v=Jjg6-xT6rJg&t=58s
This is far too small for my project
I have the code. And i now have to build the sphere
If 945 LEDs is not enough for your project then please share more details
I dont have exactly the dimensions for the sphere but i will find them and share them to you as soon as I get them.
The same for the LEDs. I don't know how many there will be....
If you're going for something much larger than 945 LEDs, then you'll want a faster board with more RAM. If you want to connect it to your phone, then you'll want a board with WiFi and/or Bluetooth. If you're using that many LEDs and you want it to be visible from any reasonable distance then you'll need a substantial power supply, or multiple supplies.
Programming flat images onto a round object is tricky, so instead make a flat model of your round object where each row of pixels is spaced individually for that row and the spacing increases and the pixels per row decreases. A simple python script can be made for sampling images to match the pixel spacing per row.
Take your total pixels and divide by 8. You should have this many per channel, then divide your data into 8-bit parallel words and write all 8 channels to a single port for fastest possible bit-banging.
Also, start with very low brightness. This is important.
I will use a led strip for my project. (I will put the link down below) The led strip that I have chosen has not any information about the LEDs only that it has 30 LEDs per meter.
Link to the LED strip:
How many LEDs in total do you envisage using and how will you lay them out so that you can show images ?
I have sent the LED strip that i am going to use instead of LEDs. I don't know exactly how many LEDs it has but you can check.
I plan to 3D Print a sphere in two parts to lay the LED strip on.
Area of a 5050 Neopixel: 25mm^2
Surface area of a sphere: 4π r^2
You can probably get by with linear Neopixels shaped like longitude lines, meeting at the poles and spread at the equator.
As you will have seen from the video that I linked to that will not result in a grid if LEDs with even spacing
And why that?
Also if its not going to work or not posible please tell me how but with a led strip and not LEDs
We’re not saying it won’t work, or that you can’t do it, but I think you’ve vastly underestimated the hardware, software and maths to develop this project.
There a lot of inputs you have to find before approaching this…
Number of LEDs, the layout and dimensions of the sphere and matrix, the refresh rate and many others- before you choose the processor or system architecture.
Note how lines of longitude on the Earth are not parallel with each other. Your LED strips will not be parallel with each other so the LEDs cannot form a regular grid pattern
Then how can I do it with a LED Strip? I am following currently this video: https://www.youtube.com/watch?v=l0WGbmc9_4Q&t=54s. Please check it out because it shows the 3D Design that I plan to print.
I am sorry but I have sent the LED Strip that I will use but don't know the refresh rate—the same with the board. I am planning to use Arduino UNO.
What is it that you want to display on the sphere ?
If it is images then you really need a square grid pattern but if it is animations then it will not matter so much
Not strictly true… you can algorithmicslly distort the ‘square’ image to wrap it around the surface, or ‘project it’ it mathematically. Both are well established methods, but will require a lot more than a UNO to handle the perspective adjustments in real time.
As for refresh rates, that is only slightly dependent on the LED strip, more so the processors ability to pump data out fast enough, and the number of strings involved.
The UNO memory will limit you to a fairly small ‘mesh’… let’s call it that instead of a grid, string or matrix. Think about 3D modelling used to cast a map onto a sphere or other surface.