I'm a bit out of my league on this one. I need to take realtime data from a serial source and display it in a "retail display" type of fashion. My PLC sends data out via RS232 (I also have RF485 ...

They used the webaudio API to send serial data to a remote Arduino. The hack uses a FET, a capacitor, and a few resistors. They didn’t quite build a real modem with the audio.

Before you can send data you must lower (ground) the Storage clock or Latch pin. Once you are done sending data you then raise it (+5v) to set the storage register and show output. Serial Data: ...

My model uses the car's OBD-II port to connect to an Arduino microcontroller, which is programmed to display the car's speed on a 7-segment display. A fresnel lens is used to optically collimate ...