Help for sensor map EMAX - EM3551H

I finally managed to decode my station. I searched the docs and certain pages and I created a file that works with this type of station. (see picture) Mine is a Raddy MN6 lite.

This model exists on different brands. if you using rtl_433 and your driver is Emax - EM3551H it will work. it's easy to modify.

Here is the step to decode it with weewx

1) sdr.py doesn’t provide a function that converts degrees Fahrenheit to Celsius so paste this code to sdr.py after # utilities for inline unit conversions. respect the None! (utility functions start from line 169)

def to_C(v):
    if v is not None:
        v  = 5 / 9 * (v - 32)
    return v

2) Always in sdr.py after the class packets: towards the line 393-394 paste this code.

class EmaxEM3551HPacket(Packet):
    # {"time" : "2024-10-25 17:51:33", "model" : "Emax-EM3551H", "id" : 1001, "channel" : 4, "battery_ok" : 1, "temperature_F" : 55.700,"humidity" : 95, "wind_avg_km_h" : 0.000, "wind_max_km_h" : 0.000, "wind_dir_deg" : 169, "rain_mm" : 0.000, "mic" : "CHECKSUM"}

    IDENTIFIER = "Emax-EM3551H"

    @staticmethod
    def parse_json(obj):
        pkt = dict()
        pkt['dateTime'] = Packet.parse_time(obj.get('time'))
        pkt['usUnits'] = weewx.METRIC
        sensor_id = obj.get('id') # changes every time you reset the outdoor sensor
        pkt['battery'] = 0 if obj.get('battery') == 'OK' else 1
        pkt['temperature'] = to_C(Packet.get_float(obj, 'temperature_F'))
        pkt['humidity'] = Packet.get_float(obj, 'humidity')
        pkt['wind_gust'] = Packet.get_float(obj, 'wind_max_km_h')
        pkt['wind_speed'] = Packet.get_float(obj, 'wind_avg_km_h')
        pkt['wind_dir'] = Packet.get_float(obj, 'wind_dir_deg')
        pkt['total_rain'] = Packet.get_float(obj, 'rain_mm')
        pkt = Packet.add_identifiers(pkt, sensor_id, EmaxEM3551HPacket.__name__)
        return pkt

3) close and save sdr.py

4) The sensor map must be put in weewx.conf

##############################################################################

[SDR]
    # This section is for the software-defined radio driver.

    # The driver to use
    driver = user.sdr
    cmd = rtl_433 -M utc  -F json

    # collect data from Emax-EM3551H
    [[sensor_map]]
        windDir = wind_dir.1001.EmaxEM3551HPacket
        windSpeed = wind_speed.1001.EmaxEM3551HPacket
        windGust = wind_gust.1001.EmaxEM3551HPacket
        outTemp = temperature.1001.EmaxEM3551HPacket
        outHumidity = humidity.1001.EmaxEM3551HPacket
        rain_total = total_rain.1001.EmaxEM3551HPacket

##############################################################################

5) close and save weewx.conf 6) reboot or restart service. That's all !!! Enjoy

support which helped me understand. thanks to the author ivan https://sh.com.hr/author/ivan/

matthewwall / weewx-sdr

Help for sensor map EMAX - EM3551H #192