I was wondering if someone has ideas about the electro magnetic radiation. Someone advised to make a 4 layer print for leds controlled with high frequencies. However most strips and matrixes (rgb-123) have only 2 layers.
I really don’t think High frequency radiation is an issue with these addressable leds. as most of them aren’t really that fast, and most aren’t putting out enough signal during the data transfer process to do any harm. if i misunderstood you i apologize.
You understood well. Do you have an idea which kind of frequencies start to do harm?
I’m still looking for info on RF noise/EMI. I’ve found this document from TI: http://www.ti.com/lit/an/szza009/szza009.pdf
They write that you should take things in account when your signals are above 50kHz. How much a pin is changed when controlling for example an APA102 at high speed?
50,000 hertz is awfully high. Most serial signals don’t reach that high, so i think you are safe. as for signal speed of that led. it mentions a signal speed of 800-1200kbps and it also mentions CKI (FCKI) frequency of 512khz, the bad English made it hard to understand so I’m not to sure what they are talking about there.
But APA102 can be run at 20Mbps. +Daniel Garcia wrote: “APA102 first speed run reports. With a strip length of ~100 leds, I can run them at 20Mhz”.
Is 1000kbps not equal to 1000kHz? In order to send 1024000 bits on a ping you need to change the pin with a frequency of 1024000Hz (= 1024kHz)?
kbps != frequency. Thats at least what I have understood. there may be some kind of exception where 1,000,000 bytes of information a second is transferred on a frequency of 1,000,000 hertz. Kilo bytes per second is a measurement of data transfer size. kilo hertz is a measurement of radio wave frequency. these two are not the same as far as I know.
I was no talking about kilobytes, but kilobits. In the technical domain it’s kind of a frequency (how often a bit changes per second).