How to Use ky-035: Examples, Pinouts, and Specs

The KY-035 is a temperature sensor module manufactured by Sensor, with the part ID "Analog Hall." It is based on the LM35 temperature sensor, which provides an analog output directly proportional to the temperature in degrees Celsius. This module is widely used in temperature monitoring and control applications due to its high accuracy, linear output, and ease of interfacing with microcontrollers and other electronic systems.

• Environmental temperature monitoring
• Industrial temperature control systems
• Home automation and HVAC systems
• Weather stations
• Educational projects and prototyping

The KY-035 module is designed for simplicity and reliability. Below are its key technical details:

• Sensor Type: LM35 temperature sensor
• Output Type: Analog voltage
• Temperature Range: -55°C to +150°C
• Accuracy: ±0.5°C (at 25°C)
• Output Voltage: 10 mV/°C
• Operating Voltage: 4V to 30V DC
• Current Consumption: <60 µA
• Dimensions: 25mm x 15mm x 10mm (approx.)

The KY-035 module has three pins for easy interfacing. The table below describes each pin:

The KY-035 module is straightforward to use in a circuit. Follow the steps below to integrate it into your project:

1. Power the Module: Connect the VCC pin to a 5V power supply (or any voltage between 4V and 30V). Connect the GND pin to the ground of your circuit.
2. Read the Output: Connect the OUT pin to an analog input pin of your microcontroller or an analog-to-digital converter (ADC). The output voltage is proportional to the temperature, with a scale factor of 10 mV/°C.
3. Calculate the Temperature: Use the formula below to calculate the temperature in degrees Celsius: [ T(\text{°C}) = \frac{V_{\text{OUT}}}{10 , \text{mV}} ] For example, if the output voltage is 250 mV, the temperature is 25°C.

• Ensure the power supply voltage is within the specified range (4V to 30V) to avoid damaging the module.
• Use a stable and noise-free power source for accurate temperature readings.
• Avoid exposing the sensor to extreme temperatures beyond its operating range (-55°C to +150°C).
• Place the sensor in a location where it can accurately measure the ambient temperature without interference from heat sources or airflow.

Below is an example of how to connect and read data from the KY-035 module using an Arduino UNO:

• Connect the KY-035's VCC pin to the Arduino's 5V pin.
• Connect the KY-035's GND pin to the Arduino's GND pin.
• Connect the KY-035's OUT pin to the Arduino's A0 analog input pin.

// KY-035 Temperature Sensor Example with Arduino UNO
// Reads the analog output from the KY-035 and calculates the temperature in °C.

const int sensorPin = A0; // KY-035 OUT pin connected to Arduino A0
float temperature;        // Variable to store the calculated temperature

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

void loop() {
  int sensorValue = analogRead(sensorPin); // Read the analog value (0-1023)
  
  // Convert the analog value to voltage (assuming 5V reference voltage)
  float voltage = sensorValue * (5.0 / 1023.0);
  
  // Calculate the temperature in °C (10 mV/°C scale factor)
  temperature = voltage * 100.0;
  
  // Print the temperature to the Serial Monitor
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");
  
  delay(1000); // Wait for 1 second before the next reading
}

1. No Output or Incorrect Readings

   • Cause: Incorrect wiring or loose connections.
   • Solution: Double-check the connections, ensuring VCC, GND, and OUT are properly connected.

2. Fluctuating or Noisy Readings

   • Cause: Electrical noise or unstable power supply.
   • Solution: Use a decoupling capacitor (e.g., 0.1 µF) between VCC and GND to stabilize the power supply.

3. Output Voltage Does Not Match Expected Temperature

   • Cause: Incorrect reference voltage in calculations.
   • Solution: Verify the reference voltage used in the formula matches the actual voltage supplied to the sensor.

4. Sensor Overheating

   • Cause: Exposure to temperatures beyond the operating range.
   • Solution: Ensure the sensor is used within its specified temperature range (-55°C to +150°C).

Q1: Can the KY-035 be used with a 3.3V microcontroller?
A1: Yes, the KY-035 can operate with a power supply as low as 4V. However, for accurate readings, ensure the output voltage is within the ADC range of your microcontroller.

Q2: How do I measure negative temperatures with the KY-035?
A2: The LM35 sensor outputs a positive voltage even for negative temperatures. To measure negative temperatures, use a dual-supply configuration or a microcontroller capable of interpreting the offset.

Q3: Can I use the KY-035 for high-precision applications?
A3: The KY-035 is suitable for general-purpose applications. For high-precision requirements, consider additional calibration or using a more advanced temperature sensor.

Q4: Is the KY-035 waterproof?
A4: No, the KY-035 is not waterproof. For outdoor or wet environments, use a waterproof enclosure or a sensor designed for such conditions.