Moteino/RFM Internal Temperature Sensor

[lilpint97]

Does anyone have any specs on the ambient temperature adjustments for the internal temperature sensor? What are we adjusting in the call?

    // Want to see what our moteino's tempature is running at as well
    Serial.print( "NODE INT: Radio Temp: ");
    float tempC =  radio.readTemperature(4); // -1 = user cal factor, adjust for correct ambient
    float fTemp = 1.8 * tempC + 32; // 9/5=1.8
    Serial.print(tempC);
    Serial.print("C, ");
    Serial.print(fTemp);
    Serial.println('F');

[john k2ox]

It allows you to correct the temp reading.  Say you compare the reading to a known temp and it's 2c degrees low.  The cal coef is +2.  So a call to readTemp(2) returns the correct temp.

Unfortunately, the temp you get is the temp of the radio chip.  The chip uses the internal temp to make adjustments to maintain rf performance vs temp.  When the radio is powered it's temp goes up. When it transmits it goes way up.

To measure the ambient temp, the chip should be powered off for a while.  Then right after applying power, read the temp.

I gave up and use a ds18b20.

john

[lilpint97]

Yeah I saw that late last night as I enclosed it, the temp got over 240C, oh well I will continue use the DS18, I have 3 of them coming off my moteino but wanted one close, may just try to add a 4th. I know seems odd, but I will be putting a write up of what I am doing. Thanks for the advice.