Problems calibrating with IR sensor

  • While calibrating, the sensor sometimes doesn't see the surface and keeps going down, till the arms come off (magnetic joints)
    I suspected it was due to the surface, I am using Filaprint on black aluminium. So I put my old Geckoplate on top. It calibrated perfectly every time.

    Is there a way to tune the IR sensor to work properly with Filaprint? It certainly is not consistent. Sometimes it senses, sometimes it doesn't.
    For now I will calibrate the manual way.

  • administrators

    It sounds to me that the surface reflection from Filaprint is a little too weak for the sensor. I don't have a sample of Filaprint so I don't know how reflective and transmissive it is to IR.

    The IR sensors with SMT optical components that I have recently started shipping may work better with it, because they have an extended dynamic range. I can reprogram the older sort to increase the dynamic range too. Alternatively, you can replace resistor R1 on your sensor by a higher value to work better on surfaces with low reflection. Depending on the age of your sensor, the existing value will be either 4k7 or 6k8.

  • Great, thanks David,
    I will have a look and increase the resistor if at all possible. By how much should I increase the resistance?

    The alternative is buy a newer version, correct?

  • administrators

    If you want to change the resistor then I suggest about 10k or 12k. Or you can send your sensor back to me and I can put the new firmware on it, which should give you more than double the sensitivity at the bottom end.

    Of course, if the problem isn't lack of sensitivity then none of this will help. I'll see if I can persuade the makers of Filaprint to send me a sample to test.

  • I still have a tiny piece left from cutting off the corners.
    I can send you the sensor and the piece of Filaprint at the same time?

    If I hold a loose piece of Filaprint under the sensor it triggers even when the sensor is not close to the bed itself. That would indicate it is not transparent?

  • administrators

    Yes, that would be helpful. It may still be transparent even though it triggers with no backing plate.

  • What was the outcome of this? I have the FilaPrint as well and are going through my options of going dc42 IR probe in the future. I'm essentially trying to figure out if there's anything I should do before putting the FilaPrint on my precision plate (i.e. paint it).

  • To be honest, I gave up as I was way too busy with the Nimble.
    So have not looked at getting it sorted out.
    But I think the problem was more on my side than the hardware side.

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