Need help with % probe

hi all

I’m after a bit of help. I’ve made a combined edge probe and touch plate for my cnc. Connected the positive to the plate and negative to my spindle. The positive is connected to port a5 on my Arduino Uno and ground to the ground pin. But no matter what I do, I can’t seam to get the probe to work, is there something I’ve missed as apart from how to use the probe, I can’t seam to find any tutorials on how to set it up.

I’ve checked the continuity on the wiring and all if fine, but just won’t work then the tool touches the plate

Hope someone can help with this

Hi and welcome to the forum. You need to add some more data to get an answer like what software you are using etc. A schematic of what you have done and a pic would help.

Given an Arduino Uno is being used, I'd guess it's most likely GRBL that's being used.

First step would be to use a multimeter and check if the Arduino pin is seeing a change in voltage. Given the description, I'd guess the internal pull-up resistor for the pin should be enabled i.e. getting a bit under 5V, or 3.3V if it's a low voltage board, with nothing connected, then when the touch probe wire is connected to ground, it should drop to 0V (it's got to be as near zero as possible).

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Originally Posted by m_c

Given an Arduino Uno is being used, I'd guess it's most likely GRBL that's being used.

First step would be to use a multimeter and check if the Arduino pin is seeing a change in voltage. Given the description, I'd guess the internal pull-up resistor for the pin should be enabled i.e. getting a bit under 5V, or 3.3V if it's a low voltage board, with nothing connected, then when the touch probe wire is connected to ground, it should drop to 0V (it's got to be as near zero as possible).

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Thanks for the advice. Still wouldn’t work but just tried connecting the neg. to my limit switches that have pill up resistors and all ni now working