This shows the log of the Arduino's counting script. Refresh manually to see it change since JS isn't running
I first have a simple Arduino script to read millis(), an internal timer that ticks every millisecond and output it to serial (USB). I then use a bash script on the server to stream the output to the HDD, where this PHP code tails the file. JS, if enabled, will request an update every second and blink the virtual LED here.