I bought 20W (12V@1.6A
- so probably ~4W optical power) laser module and wanted to control it
using Ender 3 Pro equipped with "silent" 32 bit board - V4.2.7 from Creality.
Usually, laser is controlled by utilizing Ender's fan control output, which utilizes PWM.
Unfortunately, turns out the frequency of PWM signal is ~8 Hz by default, which may be fine for controlling DC motors in the fans, but surely is too low to control a laser.
Github user "cbagwell" proposed a way to modify Marlin firmware to increase PWM frequency to 1 kHz: