So daisy chaining, like ADB(ish)? What would the power-draw limitations be? Like, would 5 daisy chained boards cause issues, would the quality of the cable become a major factor at that point etc..
The documentation of the chip was a bit confusing. 200mA was the max breakdown current not the draw. I estimate each module to draw around 60mA. 420mA if you solder in 30 white 60mW LEDs.
So, for USB 2.0 with a max output of 500mA that would mean: 8 daisy chained modules or at least 1 with backlight blasting at full brightness.
For USB 3.0 with a max output of 900mA that would mean: 15 daisy chained modules or at least 2 with backlight at full brightness.
You can also double the current with a Y-adapter-cable or if you use a powered USB hub you can raise the current to whatever the power supply says. However, the internal passthrough limit is 2A. Meaning, 33 daisy chained modules or at least 4 with backlight at full brightness.
Now the backlight numbers are assuming you want to burn away your retinas each time you look at your keyboard. Since I have no influence over your choice of LEDs I am only giving an “at least” estimate. If you use less potent or coloured LEDs or reduce the brightness setting, the power draw can reduce significantly. Also, there are going to be jumpers if you only want a caps lock or num light or want to drive these separately from the other LEDs.
All USB-C cables must be able to carry a minimum of 3 A current. So, if the cables are up to spec this shouldn’t be a problem.
And if we're daisy chaining, would future modules (trackpad, roller ball, thumb cluster keys) be options down the line? Cause that would be pretty ****in sick...
I agree, that would be ****in sick! But first I am going to test the waters with the module that everybody has a use for.