I’m helping beta test a self calibrating piezo



  • I can set the trigger duration in milliseconds, where the z output from board can be set to LOGIC 0 (Vcc goes to 0v) or LOGIC 1 (0v goes to Vcc). Vcc is based on the input, so either 3.3v or 5v depending on how I wire it. I currently have the trigger duration set to 200ms and logic 0.

    The issue I’m having is, the initial attempt resulted in the z noming. It stopping upon manually triggering the piezo. I know the piezo is triggering because I can see the status via a UART serial monitor. There’s also an LED to indicate the trigger.

    The config.g file snippet is as follows :

    ; Z-Probe - PIEZO
    M574 Z1 S2 ; set endstops controlled by probe
    M558 P8 C"io4.in" H5 F1000 T20000 ; set Z probe type to PIEZO and the dive height + speeds
    G31 P10 X0 Y0 Z-0.1 ; set Z probe trigger value, offset and trigger height
    G30 ; Probe Z

    I’m needing feedback if in fact this would be appropriate for the conditions I described. I can also modify the behavior of the piezo board by programming it, for instance changing the trigger state duration and logic (active high vs active low).



  • Given the piezo is changing the output pin to VIN or GND, it is behaving like a switch. Me personally, I'd configure it as such.



  • @Danal I’m wondering if I need the pull up resistor set with the “^”. If configured as a switch would the duration matter at all?



  • @Nuramori said in I’m helping beta test a self calibrating piezo:

    @Danal I’m wondering if I need the pull up resistor set with the “^”. If configured as a switch would the duration matter at all?

    Duration will matter only a little, within a very broad range. Mostly, it means that there is no 'bounce' to be filtered out like a regular mechanical switch.

    Pullup? More dependent on the input, I'd think. Easy enough to try it both ways.



  • @Danal thanks for the input. Got it to work extremely well so far, and the testing is coming along nicely. It was interesting to see how each type responded to the piezo. In the end a P8 was the best option.


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