If you are running a PWM at a voltage much higher than +5 volts just use a couple of resistors to drop the output voltage down to ~5 volts. I built one that ran off +9 volts and used a voltage dropping resistor couple to get it down to 5 volts. It worked fine as the TTL current is very low.
Depending on the supply voltage you might get clipping using a zener to hold the voltage constant. A simple voltage divider network would work much better. Look at Kirchhoff's Laws to find which two resistors to use. You can use values in the kohms which will drain very little current.
Yea sure a couple of resistors would do but not using the 2 dollar ground switching motor controllers anyway, I like the digital 3 channel for exact reproduction of colors for my spiro toy and I like the aesthetics of the LCD or I can make my own knob adj. pwm's from 7555 timers or use the other cheap ready made units, the whole point here was recommending a simple plug and play for SuckPit and IF he was going to use the 2 dollar motor controllers anyway at a higher Vin then a zener would allow for battery variations but he's decided to wait now anyway.........however if later using the 2 dollar motor controller units then resistors to remedy their issue as aforementioned would work although it's not the only solution it is simple.
These digital units remember your settings even after battery is removed.
Yes great stuff from China for cheap, I bought these like so much stuff I have a while back, you can see the dust on it LOL, I have more in the anti static wrappers in boxes just waiting to get used in something someday, much of it may never get used but I see a bargain and just have to grab some for later.
Thinking about this for use as a laser spiro engine I would rather junk the Chinese driver and make 3 simple linear drivers with pots so the beam won't have that annoying pulse, would be really bad on the wall making Spiro graphs, would look like those pulsed automobile tail lights. Yep needs to be analog.