LED Always ON

[hreality]

Verified my logic and the probe is functioning... Voron 2.4 r1 Octopus 1.1 never needed a diode and ran klicky standard without issue. Thing is, the LED is always on dims briefly while probing..

[probe]

Inductive Probe - DIAG7 Replaced with Klicky PCB

This probe is not used for Z height, only Quad Gantry Leveling

pin: ~PB7 x_offset: 0 y_offset: 19.75 z_offset: 6.42 speed: 4 samples: 3 samples_result: median sample_retract_dist: 3.0 samples_tolerance: 0.3 samples_tolerance_retries: 4

[karlfife]

Same issue. LED is on even when probe is NOT attached. Triggers appropriately, but same observation--slight dimming when triggering. Not sure how the circuit is built, but tried configuring signal to pull up, and pull down to no avail. Same result

[tanaes]

I recently got a batch of PCBs from JLCPCB in which half the boards were assembled with the wrong LED part number, causing the same behavior. I wouldn't be surprised if other vendors received boards with the same problem.

[karlfife]

I must misunderstand something about the theory of operation of the PCB Klicky. Since the magnetic probe itself has both NO and NC contacts, I assumed the only electrical path to illuminate the LED was via Normally Closed contact on the probe. i.e. No probe, no path to ground for the diagnostic LED. After the probe is attached, current can flow via the NC terminal through the LED to ground, causing it to illuminate. Once the attached probe is triggered, the NC circuit opens, interrupting connection to the LED, instead pulling down 'signal' to ground. I must have this wrong, otherwise, the LED could not stay lit, even if the wrong type/part.

What is the design if not as above? Must be that the circuit is totally different, e.g. with an LED zener diode with the wrong breakdown voltage (causing it to remain lit). Care to shed light if you can? If it's got the wrong LED, it seems the solutions are to not use the light, or to reach out to the vendor and ask for a replacement. Do you happen to know if it would work in a 5v configuration

[tanaes]

Ahh sorry i thought you were talking about OptoTap! Please ignore my comment then. 😅

On December 23, 2023, Github Notifications @.***> wrote:

I must misunderstand something about the theory of operation of the PCB Klicky. Since the magnetic probe itself has both NO and NC contacts, I assumed the only electrical path to illuminate the status LED was via Normally Closed contact on the probe. i.e. No probe, no path to ground for the LED. When the probe is attached, current flows via the NC terminal through the diagnostic LED to ground, causing the LED to illuminate.  When the attached probe is triggered, the NC circuit opens, interrupting connection to the LED, instead pulling down 'signal' to ground.  I must have this wrong, otherwise, even the wrong type of LED could not stay lit. What is the design if not as above? Maybe the circuit is totally different, with an LED zener diode with the wrong breakdown voltage, and that's what causing it to remain lit? Care to shed light?

— Reply to this email directly, view it on GitHub https://github.com/tanaes/whopping_Voron_mods/issues/33#issuecomment- 1868362939, or unsubscribe https://github.com/notifications/unsubscribe- auth/AB7ISAGC4XDGY6TMUP3FU4TYK43KBAVCNFSM6AAAAAA6IARXWWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQNRYGM3DEOJTHE. You are receiving this because you commented.Message ID: @.***>

[karlfife]

For what it's worth, I moved the KlickyPCB from the 24v induction probe header to a "normal" 5v endstop header. The klickyPCB now works as documented/expected.
This would suggest either 1: 24v induction probe headers behave differently than standard GPIO headers and this is expected behavior (i.e. that the documentation is wrong or incomplete), or 2: The 24v induction probe header on my CANBUS toolhead board is broken, or works differently than the ubiquitous (BTT Octopus), or 3: My KlickyPCB is defective and only expresses the defect when using 24v circuits. I'm guessing #1. If @tanaes knows the answer, a slight tweak of the doc may save some future headaches for someone.