Shown below is the photo of such a compact four-channel optocoupler module — the “SODIAL R HW-399,” built with the good old TLP281-4 photocoupler from Toshiba. Even though it’s easy to use a ...

That’s because brushless DC motors require carefully timed signals used in a process called Electronic Speed Control (ESC). [Fileark] built and ESC using an Arduino and has a couple of posts ...