Arduino-Controlled BLDC Fan Interface

I already have a universal BLDC ceiling-fan driver PCB running perfectly from mains power; what it lacks is an Arduino brain. My goal is to plug an Arduino (Uno, Nano, or whichever you prefer) into the existing driver so I can:

• adjust fan speed across its full range,
• reverse the direction on command, and
• set on/off timers,

all through a small set of physical push-buttons mounted near the fan.

What I need from you is a clean, well-commented sketch plus a minimal wiring diagram that shows exactly where every button, resistor, and logic-level signal ties into the driver board. If any level-shifting, opto-isolation, or triac/FET gating is required, please spell that out and include the component values. Debounced button handling and non-blocking timer logic (e.g., using millis()) are a must so the three features work smoothly together.

Acceptance will be based on:
• uploading the compiled sketch to my Arduino and seeing reliable speed steps, direction toggling, and timer shutoff,
• clear pinout mapping that matches my BLDC driver’s control inputs, and
• brief notes on safely powering the Arduino from the fan’s existing supply or an external 5 V source.

If you’ve integrated Arduinos with ceiling-fan or BLDC drivers before, let me know—otherwise a quick explanation of your approach is fine.

universal BLDC ceiling-fan driver PCB