How to detect ice with sensor in outdoor unit for airconditioning


Im seeking to detect when there is ice in my outdoor unit and then turn up the heaters to melt it. But I came to a problem. How to detect ice? There is no sensor specifically for that. My first thought was why not with soil moisture sensor.

I ran some tests and the result came that it gave around 300-400 in water, 1024 when dry and 1024 when in ice. I dont see how is that so...

So do any one have any ideas how to detect ice and if soil sensor is ok what have I done wrong?


The best way to detect ice is to measure the air flow thru the cooling coil. When ice is present , it restricts the air flow relative to when there is no ice

If airflow is too hard to measure then maybe you can use a light-beam that gets interrupted when ice forms.

The thing is I have to detect ice that is minnimum 5 mm thick.. and beam would be stopped with water too, which aint fine.

Do any of you know how accurate are those IR avoidance modules for cars and robots? do they sense 5 mm change? and would it work on ice?

This link will tell you how a heat pump detects frost. Perhaps you can glean some ideas from it.



How did you end up detecting your ice?