Home JGAurora A5 & A3S Modifications & Upgrades

IR Sensor Sometimes Triggers Too Early

Has anyone else had/solved the issue where the IR sensor sometimes triggers several mm too high when homing. It then tries to bed level and fails because it incorrectly sensed z home as much higher. I'm assuming this is to prevent damage.

This problem usually happens when beginning a new print after I have completed a print with at least 5-10 mm z height. Manually lowering the z height before beginning a print resolves the problem temporarily.

In testing the ir probe, I notice that the indicator light triggers at the proper location and triggers with a dimmer and more sporadic light at a much further distance.

This problem didn't exist for the first several months of using the IR sensor and only cropped up recently.

Sensing at incorrect location:



Sensing at correct location. Note the brighter indicator light.

Comments

  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    You can only try to ajust the IR LEDs like they say in the manual but I cant recommend that.
    That IR probes never work well, I had that probe to.
    Alone the design of it is stupid, who places the ELKO directly on the lowest and hottest place? That Elko doesnt hold up for a long time.
  • cs2000cs2000 Posts: 56🌟 Super Member 🌟

    Not personally had that. The whole point of the circuitry is that it decidedly latches On or Off, not half on (the dim LED state you're seeing).

    As Der_Muck says, the design is a little flawed, the capacitor is 105 degrees c rated and sits a few mm above a 100c + heated bed and a 240c nozzle. Its likely your capacitor has failed/is failing. Grab another module, swap it out and you'll probably be fine.

    Interestingly, the capacitor is put there for a reason. It blocks light from shining directly from the IR emitter to the receivers and saves the designer from having to use something else like a raised PCB section to do the same thing. Great in theory, but bad in practice for the reasons mentioned above.

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