How to Use ky018: Examples, Pinouts, and Specs

The KY-018 is a temperature sensor module manufactured by ESP32 with the part ID 18. It is based on the LM35 temperature sensor, which provides a linear analog output proportional to the temperature in degrees Celsius. This module is widely used in temperature monitoring and control applications due to its simplicity, accuracy, and ease of interfacing with microcontrollers.

• Environmental temperature monitoring
• HVAC (Heating, Ventilation, and Air Conditioning) systems
• Industrial temperature control systems
• Weather stations
• Home automation projects
• Educational and prototyping purposes

The KY-018 module is designed for accurate and reliable temperature sensing. Below are its key technical details:

The KY-018 module has three pins for easy interfacing:

The KY-018 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 3.3V if supported by your microcontroller) and the GND pin to the ground.
2. Read the Output: Connect the OUT pin to an analog input pin on your microcontroller to read the temperature as an analog voltage.
3. Convert Voltage to Temperature: Use the formula below to calculate the temperature in degrees Celsius: [ \text{Temperature (°C)} = \frac{\text{Analog Voltage (mV)}}{10} ]

Below is an example code snippet to read temperature data from the KY-018 module using an Arduino UNO:

// KY-018 Temperature Sensor Example with Arduino UNO
// Reads the analog output from the KY-018 and converts it to temperature in °C

const int sensorPin = A0; // KY-018 OUT pin connected to Arduino analog pin 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 from the sensor
  float voltage = sensorValue * (5.0 / 1023.0); // Convert ADC value to voltage
  temperature = voltage * 100.0; // Convert voltage to temperature (10mV/°C)

  // 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
}

• Power Supply: Ensure the module is powered within its operating voltage range (4V to 30V). Exceeding this range may damage the sensor.
• Analog Pin Resolution: For accurate readings, use a microcontroller with a high-resolution ADC (e.g., 10-bit or higher).
• Noise Reduction: Use decoupling capacitors near the power pins to reduce noise and improve stability.
• Temperature Range: Avoid exposing the sensor to temperatures beyond its specified range (-55°C to +150°C) to prevent damage or inaccurate readings.

1. No Output or Incorrect Readings

   • Cause: Incorrect wiring or loose connections.
   • Solution: Double-check the wiring and ensure all connections are secure.

2. Fluctuating or Noisy Readings

   • Cause: Electrical noise or insufficient power supply filtering.
   • Solution: Add a 0.1µF decoupling capacitor between VCC and GND pins.

3. Output Voltage Does Not Change with Temperature

   • Cause: Faulty sensor or incorrect analog pin configuration.
   • Solution: Test the sensor with a multimeter and verify the microcontroller's analog pin setup.

4. Temperature Readings Are Inaccurate

   • Cause: Calibration error or incorrect voltage-to-temperature conversion.
   • Solution: Verify the conversion formula and ensure the power supply voltage is stable.

Q1: Can the KY-018 module be used with a 3.3V microcontroller like ESP32?
A1: Yes, the KY-018 can operate at 3.3V. However, ensure the output voltage range is compatible with the ADC input range of your microcontroller.

Q2: How do I measure negative temperatures with the KY-018?
A2: The LM35 sensor outputs a negative voltage for temperatures below 0°C. Use a microcontroller or circuit capable of reading negative voltages, or add a level-shifting circuit.

Q3: Can I use the KY-018 for long-term temperature monitoring?
A3: Yes, the KY-018 is suitable for long-term use. Ensure proper environmental protection if used in harsh conditions.

Q4: What is the maximum cable length for connecting the KY-018 to a microcontroller?
A4: The maximum cable length depends on the quality of the cable and the environment. For best results, keep the cable length under 1 meter and use shielded cables in noisy environments.