How can I set parameter if there are multible instances of the sensor class?

  • Hi (once again),

    I just try to create my own sensor class within NodeManager. I have Chirp sensors ( at home for monitoring the mositure of the soil of my plants.
    My current (minimal) implementation of the class works fine, but now. I have 3 problems:

    1.) The sensor produces 3 sensor readings (Capacitance,Light and Temperature). This creates 3 instances of my new Chirp class. If I try to set the class specific parameter (I would like to set an individual capacitance measurement offset because of the scattering of each individual sensor hardware) like in your description:

    SensorCHIRP* myCHIRP = (SensorCHIRP*)nodeManager.getSensor(nodeManager.registerSensor(SENSOR_CHIRP));

    It sets the parameter only in the last instance of the class, but this is not the instance for moisture (ok, I can rearrange the initialization, but maybe there is a better way).
    The only way I found, is to substract 2 from the sensorID:


    because it is the first created instance of the class.

    Maybe my last c++ project was tooooooo long ago ....

    2.) that means: if I want to set (as an example) the setTrackLastValue parameter, I have to do this for all 3 instances?

    3.) every instance of the Chirp class does its own sensor initialization. It there a way to do this only once?

    If my Chirp class have no further errors (and a way to deal with the above), you can include this class into your package, if you wish ...

    Best regards and THANKS for this really helpfull NodeManager library

    Frank (Betonmowew)

  • ok ok ... I found a way: the word static is the key !

    I have declared all my needed variables as static and do a global initialization in NodeManager.cpp just in front of the code for my Chirp methods. The -2 is not necessary any more and with a helper variable, (address of the sensor) there is only one sensor initialization/reset.

    Now, only question 2 is open ...

  • Contest Winner

    Hi, the workaround of using a static variable is ok but of course would not necessarily work well in any situation but I'm glad you got it working somehow :).
    However you're right, this is a known issue in NodeManager. should tell you why and answer your question #2. The solution unfortunately is not that easy since would require re-thinking the way sensors are mapped to child IDs. Work is in progress though 🙂 (

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