Radds 1.6 and inductive probe

[carlom180]

Basic Information:

Printer Model: CUSTOM CoreXY
MCU / Printerboard: RADDS 1.6
`klippy.log

I have a dubt about connecting an inductive probe to my Radds 1.6.
Usually I connect this kind of probe to “Z-min” connector, but RADDS gives only 3.3v, while probe needs 6-36v.
So… if I connect ground and V+ to the power supply (24v) and signal cable to z-min signal pin, I’ll burn all ?
Thanks

[EddyMI3D]

@carlom180

while probe needs 6-36v.

What probe do you have?

[carlom180]

It’s this:

I could use a bltouch, but I’ll have to solder pins on my Radds board so I have decided to do some experiments with this…

[Sineos]

Without any warranty whatsoever:

• These probes are typically NPN-NO
• Connect + and - to a suitable voltage source, e.g. 24V
• Connect signal to the Z-min endstop

Before doing this, I’d recommend using a voltmeter and measure resistance between GND and signal. When nothing is detected it should have unlimited resistance and upon detection the resistance should drop to 0.

…and there should be no voltage measurable between GND and signal.

[mykepredko]

You can use the probe with a diode inline as shown here:

The silicon diode (literally any type) will prevent any dangerous voltages from passing from the probe to the controller board.

[Sineos]

Good advice, although I’d prefer a fast and low drop Schottky diode, e.g. BAT85 over some general 1N4 something.

[carlom180]

Thanks for all!