<p>➀ A rev counter prototype for a CNC lathe using Arduino Pro Micro faces jitter (±3 counts) due to mechanical imperfections but functions accurately on signal generators;</p><p>➁ Limitations in Arduino's 8-bit PWM resolution (via analogWrite()) prompt plans for custom 10-bit code, while a safety feature prevents unintended motor activation;</p><p>➂ 3D-printed housings and open-source code highlight iterative hardware/software integration for workshop deployment.</p>