5V input to trigger PC shortcut

Hi everyone!

We are (Trying) to build a project which will automate machinery in our warehouse.

We have a lot of the back work done, we can get machines to load, start programs etc. However, we've hit a wall when our machines finish a job, we need to trigger the PC to know it can move onto the next sequence.

The machines have a status output, this runs at 24V whilst the machine is running, intended to run a red light, I've converted this to 5V so my Arduino doesn't go bye bye.

What I'm looking for help with, is a way I can alert my PC from the Arduino when the voltage drops from 5V to 0V indicating the machine has finished, the trigger the PC receives can be pretty much anything. However, something like a keyboard input would be more than sufficient as we can have the software we have running listen out for "ALT+CNTRL+F" for example.

Any advice on how we would go about this would be massively helpful!


As for hardware, you can emulate the keypresses with the Arduino Micro, Leonardo, or the SparkFun Pro Micro if space is tight.

As for firmware, you will use the Keyboard library:
The library comes with some tutorials, linked from that page, which will get you started.

You could have an Arduino detecting the voltage on a digital input and then send that information across RS232 to the computer for it to act on.

I did the @pert’s recommendation to implement various sequences for games and also for the MacOS “three finger salute”, I recall stumbling over key combos, so check out

which covers it well. You just need an Arduino that can do it, or you’ll get involved in way too much work. Cheaper end to end to just have a board with the necessary feature(s).