Help to create a pass detector for 24v machine

Projects General Guidance
1

Hello from Barcelona.

I have an old CNC machine that we use to produce little metal pieces.

When the pieces haves been conformed they are cutted and they must fall inside a furniture.

The problem comes when any of the pieces doesn't fall into the furniture because is possible that it remains where the next piece is going to be conformed.
That can produce a crash between the upcoming piece and the forming tools.

Time ago the cnc machine was equiped with an antifailure system that basically was a plastic tube where the finished pieces passed trough their way to the furniture and if any of the pieces didn't fall then the machine stopped before starting the new piece.

I want to clone this method using an Arduino board. The goal is to get a 24v signal from the CNC machine, wait for a determinated amount of time for the piece to pass through a ring (or another pass-detector) and if there is not piece then send a 24v signal back to the machine (as the old original system did).

Something like this:

The first issue we have to deal with is the fact that the machine operates natively at 24v so we are going to need a shield to this kind of voltage and to send a similar signal to the machine in the case that we want to stop it.

Any advice on what kind of shield would fit in our needs will be trully apreciatted.

As we want to clone the old system we plug the Arduino directly from the shield to the machine inputs and outputs (we can code the machine to send a signal to the arduino when the piece is produced).

I don't know what would be the best way of detecting the pass or not of the finished pieces. The pieces are as big as a paper clip.

Thanks in advance for any idea.

Greets from barcelona

2

Perhaps using a relay is the easiest way to send a signal the device.

Detecting the particles can be done in the same way a metal detector works.
The ring in your picture could be a coil with a radio frequency.
If the frequency changes, some metal passed.

3

Erdin:
Perhaps using a relay is the easiest way to send a signal the device.

So you recomend to use a relay to send a 24v signal to the CNC machine, but is there any way intead of buying a shield to recieve the signal from the machine?

Erdin:
Detecting the particles can be done in the same way a metal detector works.
The ring in your picture could be a coil with a radio frequency.
If the frequency changes, some metal passed.

Thanks for pointing the idea of the frecuency change. I'm going to look for examples of this in the forum.

Greets from Barcelona