PR55-57D Soil Moisture "this is an unknown device" and red led

I have a new PR55-57D soil moisture sensor and have just now gotten to deploying it. I am noticing two things:

  1. When I turn the sensor on, a red LED light turns on. I do not believe I have seen this with my other sensors. What does the red light mean?
  2. Serial output of the NCD MQTT gateway displays This is an unknown device.

I have updated the firmware of the gateway as of July 11, 2021. I have also tried pulling any new changes in the telliottosceola/Flash_Script.git repo, but it seems I am up to date and the last pushed commit was April 20, 2021.

its a status LED.
every time device sends a successful packet it will blink one.
if there is an issue with probe it will blink twice
if there is an issue with radio it will blink 3 times.
@TravisE_NCD_Technica can you add this sensor support when you get a chance.

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Thank you, @Bhaskar . I understand the blinking, but… what about when the status LED is solid red (not blinking) ?

if its always on that indicates the device cant boot.
does it do after power cycle as well ?
are you getting wireless packet ?

This is the product manual linked on the product page:

This type 3 sensor is already supported in the MQTT Gateway.
Is that the wrong guide for the sensor? If so can you provide information to integrate support to the MQTT Gateway?

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@TravisE_NCD_Technica checkout this table in the manual

Soil Moisture Temperature and EC Sensor

@Bhaskar Got it. I will get support added this afternoon. @ybakos I will let you know when it’s added so you can update your MQTT Gateway.

@Bhaskar @ybakos
Support is added. You can update your MQTT Gateway firmware and it should work with the sensor.

Here is the code snippet added to add support for the sensor. @Bhaskar I don’t have one of these to test so if anything looks out of place please let me know.

      if(len < 25){
        Serial.printf("Sensor type 69, Length too short, it was: %i\n", len);
        return false;
        json["Type"] = "Soil Moisture Temperature and EC Sensor";
        json["SKU"] = "";

      dataObject["moisture"] = (float)((data[9]<<24)+(data[10]<<16)+(data[11]<<8)+data[12])/100.00;
      dataObject["temperature_c"] = (float)((data[13]<<24)+(data[14]<<16)+(data[15]<<8)+data[16])/100.00;
      dataObject["ec"] = (float)((data[13]<<17)+(data[18]<<16)+(data[19]<<8)+data[20])/100.00;
      dataObject["salinity"] = (float)((data[21]<<17)+(data[22]<<16)+(data[23]<<8)+data[24])/100.00;

      rDevice = true;
      Serial.println("packet complete");
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@TravisE_NCD_Technica looks good. there is a sensor outside the office. it should be sending data. if you want use that one to test

Ok. I’ll take a look this afternoon.

Thanks @TravisE_NCD_Technica , firmware updated and gateway is able to handle the sensor.

But, @Bhaskar the status LED is still red, even after resetting / power cycling. It is indeed sending data to the gateway, but my concern is the power draw on the LED and the fact that it being on is not “normal” operation.

Should I request a replacement? This one isn’t for something mission-critical, so I can see how long the battery lasts despite the status LED being on, before complaining, haha.

yea i will recommend sending back for an repair. their might be a short which is keeping it alive all the time.
if you are in rush you can just clip the led and kill it all together.

I’ll try it out for a bit and see if the battery life is significantly impacted, and will circle back if there is an issue.