just PWM, why not

For a Charlie plexed cube you can only have basically one LED lit at any point in time, you just have to very quickly loop over all the LEDs that need to be lit and give each one a small windows to be visible. Then rely on persistence of vision to make it look like they are all active at once. To dim an LED you just need to turn it on for less time or skip it for some update cycles. You cannot use PWM for this, each pin needs to be controls many LEDs and it is toggled in a non regular period. Note that because of this all the LEDs are quite dim to start with as they are only ever on for a fraction of the time.

This question also came to my mind as it was one (of a few) issues that I also could not solve when I attempted to build a LED cube 10 years ago using a Raspi of the first gen. I also hit the activity flickering issue, but could solve it with OS priority settings (was about to switch to Realtime Linux at a later point for higher reliability). In the end I was unable to solve that dimming issue as with higher "framerate" to simulate PWM (or rather BAM) modulated dimming I got stuck with some sort of "phantom" issue, where the previous LED I had active was not turning off fast enough. Until today I could not solve that issue but I still have learned one bit or another over the years to undertake a new attempt, if I had the time nowadays 🙂 Great project and explanation!

Yeah 😂. That's definitely the plan moving forward, but for these first few videos, the projects were already done when I decided to do a video.

@@mal2ksc Yes, I already saw that ;-) I know that it is already an awful lot of work, but investing the additional time and material would be beneficial for the project. There are some guys here on UKposts presenting this as a kind of “artistic light installation”… And to have a whole m3 of it in the middle of your living room makes it really stunning. I myself hate this kind of never-ending work and try to avoid it, but if somebody even goes this _extra_ mile… ;-)

You're right. Thanks! I didn't know that.

Thought the same, its unneccessary complex design bringing unneccesary drawbacks. Just shift reisters for the colums and you can live with using 8 pins for a 5x5x5 matrix

@@flipschwipp6572 It is just a proverbial "thought experiment", the world gets pretty boring when everyone always converges on what, at the time, is optimal. No different than the guy who calculates pi with relays.

So, it was easy for you at the first time? Or for anyone who is starting out with this? I see your comment more as loathing than kind and helpful.

It may sound more complicated, but if you do something like that, you’re probably going to use libraries for the software, right? This in theory can be done without all of that. Also, using ws2812b only requires one wire going through all leds, so the wiring is a lot more simple

@@fritzlb that is the complex part, not using existing Libaries some one already did. You have to read the datasheets, set the registers right. Especially if you have to read the reference datasheet, the device datasheet and multiple application notes to get all informations you need.

Only setting the registers isn't that hard or complex, also there are enough tutorials online for common architectures Completely bitbanging the ptotocol in asm might be a challenge tho