Hi Chris, thanks for your support.
I finally made one using the Dew Heater v.6.2.3. Most hardware is connected and working as intended. I tested it on PC and Button mode; both of these modes working great.
The sensors that I have used are AM2320 and DS18B20 with 16x2 LCD and 4ch Mosfet board. I haven't connected any heater output jacks yet, but just tested the whole thing completely using ice packs (to cool down DS18b20) at room temperature.
PC app is truly great. I love it. It displays lot of useful information. Thank you very much for making this app
How I made it finally work after 3 days of disappointment?
By adding 2 sec. delay. I figured it out by random testing only:
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sensorAmbient.ino file
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// get ambient temp & humidity data from AM2320 or BME280 sensor
#ifdef AM2320_ON
void resetAmbientSensor() {
am2320.begin();
}
void getAmbientData() {
// read ambient temp and humidity - takes 100s of msec?.
humidityAmbient = am2320.readHumidity();
delay(2000);//EXTREMELY IMPORTANT DELAY
temperatureAmbient = am2320.readTemperature();
calcDewPoint();
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This one line changed everything - from disappointment to joy

I hope this will help someone having similar issues of getting readings from AM2320 sensor.