HR202 sensor module

HR202

Hi I got a HR202 sensor module with a LM393 comparator board, I am planning to use it for humidity data log in my room. I got a code that was meant for hr202 sensor but when I program it it seem the humidity is stuck at 66% for most of the time. Is that suppose to happen? If not is there a way to solve this problem?

Bellow is the code

// HR202 Humidity Sensor Arduino Code

const int sensorPin = A0;  // Analog pin connected to HR202 sensor

void setup() {
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(sensorPin);  // Read analog value from the sensor
  float humidity = calculateHumidity(sensorValue);  // Convert sensor value to humidity percentage
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.println("%");

  delay(2000);  // Delay between readings (adjust as needed)
}

// Function to calculate humidity based on sensor value
float calculateHumidity(int sensorValue) {
  // Conversion formula specific to HR202 sensor
  float humidity = (float)sensorValue * 100 / 1024;
  return humidity;
}

Please give a link to the board you have.

What is the purpose of the comparator on that board?
Commonly, it would be used to give you a binary (yes/no) indication of whether the humidity is above a certain value or not...

The LM393 is integrated into the sensor module and there was only a digital output no analog output so i assume that means the sensor module is like a switch?

That's correct. The little pot set the humifity trip point.

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I still don't know what you need to get, but as @awneil said, it seems to me that this comparator will give you just on/off based on a threshold defined by the trimmer, not the humidity percentage value.

Said that, I have just three words: throw it away.

IMHO that HR202 is a horrible sensor, almost useless and unreliable. Please remember you don't read humidity value, but RH, Relative Humidity, as it's "relative" to temperature. So I suggest you to get a DHT11 instead: it costs a few cents more than HR202 but it is a more commonly used and reliable "Digital Temperature and Humidity Sensor", and it has a specific library to manage the read values.

PS: If you need wider range and precision there are the DHT22/AM2302, not as cheap as DHT11 but we aren't talking about many bucks...

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Exactly: so your analogRead() is only ever going to return one of two values - you are never going to get a continuous humidity reading from this board.

You either need to "hack" the board to get access to the analogue value, or get a different board which does give a continuous humidity reading.

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I see, thanks for the info. Js asking is there other humidity sensor other than DHT11 and DHT12?

yes, there's a huge variety of sensors out there!

eg, here's a couple more - which also include pressure & temperature:

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I see tq for the info :heart:

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