I built a single touch probe that shorts one of atmega pins to ground. When I test it with a piece of wire things work fine, but when I attach everything to my repstrap triggering of the probe kills the sanguino. I've tried adding a 100k ohm resistor to the path, but so far with no success. What am I doing wrong? How should one design such a probe? https://reprap.org/forum/read.php?13,23512,23512#msg-23512 Fri, 11 Sep 2026 12:48:51 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?13,23512,23535#msg-23535 https://reprap.org/forum/read.php?13,23512,23535#msg-23535 KaiBackman Controllers Fri, 15 May 2009 21:31:39 -0400 https://reprap.org/forum/read.php?13,23512,23520#msg-23520 https://reprap.org/forum/read.php?13,23512,23520#msg-23520
Try something with shorter wires and/or twisted pairs and parallel capacitive or serial inductive filters ...

Viktor]]> VDX Controllers Thu, 14 May 2009 14:58:41 -0400 https://reprap.org/forum/read.php?13,23512,23519#msg-23519 https://reprap.org/forum/read.php?13,23512,23519#msg-23519 -------------------------------------------------------
> When moving or rubbing/pushing plastic components,
> you can easily accumulate some kilovolts, so you
> should apply some safety against this too ...

This happens with just metal components, I'm running the probe against some PCB substrate. I think it has something to do with the spikes generated by the sudden close of the circuit. Maybe a few caps and current limiting resistors will help?]]> KaiBackman Controllers Thu, 14 May 2009 12:13:36 -0400 https://reprap.org/forum/read.php?13,23512,23513#msg-23513 https://reprap.org/forum/read.php?13,23512,23513#msg-23513
When moving or rubbing/pushing plastic components, you can easily accumulate some kilovolts, so you should apply some safety against this too ...

Viktor]]> VDX Controllers Thu, 14 May 2009 03:13:01 -0400 https://reprap.org/forum/read.php?13,23512,23512#msg-23512 https://reprap.org/forum/read.php?13,23512,23512#msg-23512
What am I doing wrong? How should one design such a probe?]]> KaiBackman Controllers Thu, 14 May 2009 02:31:46 -0400