Suggestion: create a Sparsnas class that handles everything related to the received package

[fredrike]

It's been bugging me the whole day yesterday and I think the sparsnäs decoding should be extracted to a separate class. This will enable easy access to multiple sensors like @Sperra suggested and also much cleaner code base.

My suggestion is that we move most parts of interruptHandler() into a class like this one:

class Sparsnas
{
private:
    uint32_t my_sensor_id;
    uint16_t my_pulses_per_kwh;
    uint8_t my_received_data[21];
    uint8_t my_decrypted_data[21];

 static:
    bool check_crc(unit8_t data[18]);

public:
    Sparsnas(uint32_t sensor_id, uint16_t pulses_per_kwh, uint8_t received_data[21);
    bool isValidPackage();  // This will do the decryption and crc_check.
    uint16_t getPower();
    float getWatt();
    uint16_t getSequence();
    char* getStatusString();
    char* getJsonString();
};

This means that https://github.com/fredrike/EspSparsnasGateway/blob/ce54c56d7d22fca426e0615b3bc3ebdf0c01dba9/src/RFM69functions.cpp#L315-L464 can be replaced with (and that the Sparsnas class can be reused in other projects):

    // Read 20 bytes
    for (uint8_t i = 0; i < 20; i++) {
      TEMPDATA[i] = SPI.transfer(0);
    }
    Sparsnas* sp = new Sparsnas(SENSOR_ID, PULSES_PER_KWH, TEMPDATA);

    if(sp->isValidPackage()) {
        mClient.publish(mqtt_status_topic, sp->getJsonString());
    } else {
        mClient.publish(mqtt_debug_topic, sp->getJsonString());
    }

We might need to add some fancy handling of LEDs and such (in my example above), the class should be native c++ but this is a base :).

[fredrike]

We could use the code from https://github.com/merbanan/rtl_433/blame/master/src/devices/ikea_sparsnas.c (it is quite clean). Perhaps @merbanan can help with that (would be really nice to "borrow" his sensor bruteforce part.

[merbanan]

@slundell is the original author. But you are free to use the code under the gplv2 license, if you need another license you have to ask the original author.

[bphermansson]

Looks like a good idea. Why don't make a test branch that uses @merbanans code?

[fredrike]

Looks like a good idea. Why don't make a test branch that uses @merbanans code?

I'll take a look at this after vacation time (perhaps even in November 😄). I need to solder a dev unit as I've actually moved to production now.