Make a $25 Full 3D Probe

[john-100]

OK , I will have to study your video again !!

taking your point the probe has to be inserted all the way in and the LED will not be visible

this will be closer to what it should be



John

[narrobb]

Buzzer then LED, they both come together and all probes of this type will have both. The buzzer limits the current to the LED. So it was your first layout but replace the 330 resistor with the buzzer.

And this is only if one would want to hear the buzzer (pretty hard with the machine moving) but can be useful for manual testing. Also, the same layout without adding +5V to probe works as well, those who are not going to add the +5V, they can also use it manually by looking at the probe LED in the PP page or MACH3 LED contact pages.

I wouldn't worry about the 100 ohm you connected on the open drain output, its opto-isolated input to their board (see attached)

And to clarify your bottom note on the image for everyone, "output-low until edge detected" just means Normally Closed.

OK , I will have to study your video again !!

taking your point the probe has to be inserted all the way in and the LED will not be visible

this will be closer to what it should be



John

[john-100]

Hi narrobb

I have added the input circuit from the PCNC manual to the modified probe circuit



John

[narrobb]

Looks good, thanks for your input.

Hi narrobb

I have added the input circuit from the PCNC manual to the modified probe circuit



John

[mountaindew]

Hi narrobb

I have added the input circuit from the PCNC manual to the modified probe circuit



John

You guys lost me on this!
What does a battery operated edge finder have to do with the tormach din connector for probes?


Sorry it does help to watch the videos. Setting here with watching boring cam simulations and checking dimensions on cad system. takes up most my system so I'm reading not watching much

[narrobb]

You guys lost me on this!
What does a battery operated edge finder have to do with the tormach din connector for probes?

Check my video at the beginning of this thread.

[john-100]

Hi mountaindew

unless you have a spark erosion machine to "drill" a blind hole in a 10mm ball bearing
to add the attachment point for the spring
the Chinese probe just provides some inexpensive parts for narrobb's project





John

[crjohnson]

Hi guys,
Digging this thread up as I was wondering what resistor values would be required to make this work with a 24vdc power supply?

I have a UCCNC + AXBB-e setup on my mill, the probe input terminals run on 24vdc.

[jwatte]

The main question is what voltage the input on your probe port wants to see, and whether it's current operated like the Tormach one.

If it can tolerate 24V, then you can bump up the LED resistor to maybe 2.2 kOhm or so, although details depend on the input impedance of your probe port.

However, if it can't tolerate 24V, you will need to also add a voltage divider of some sort, so the circuit would need to be different. And if it's not current operated, then you'd ALSO need a different circuit.

[crjohnson]

Thanks for the reply jwatte.
These AXBB-e boards want to see 24vdc on the isolated inputs port. I have wired up my limit/homing switches (and the rest of the machine really), exactly as shown in the manual below and it works great.

My knowledge of electronics is a bit limited when you start talking of impendance and voltage divider circuits unfortunately. I can build/solder circuits no worries, but not really design!

[jwatte]

If the input is 24V tolerant, then the same circuit as below, but perhaps with 2.2 kOhm resistor, should work fine!
Fine-ish, actually -- the diode will have some voltage drop, and the resistor will also have some voltage drop.
Depending on the input impedance of the "24V" input, you may need to change the resistor; there's no way to know for sure without knowing the specification of the input.
Unfortunately, the diagram doesn't specify, so it's impossible to know for sure.