ML8511 UV Sensor Arduino Library

This is an Arduino library for interfacing with the ML8511 UV sensor, a compact ultraviolet (UV) sensor that measures UV intensity and calculates the UV Index. The library provides a simple and flexible API to monitor UV exposure with support for multiple units and calibration options.

Features

• Measure UV intensity in various units (e.g., mW/cm², W/m², μW/cm², MED, etc.).
• Calculate the UV Index based on sensor readings.
• Configurable over-sampling for improved measurement consistency.
• Custom calibration with user-defined voltage values.
• Support for multiple microcontroller platforms (e.g., ESP32, RP2040, STM32, SAM3X8E).
• Optional serial logging for debugging.

Supported Platforms

• Arduino (AVR-based boards)
• ESP32
• Raspberry Pi Pico (RP2040)
• STM32F1 and STM32F4
• Arduino Due (SAM3X8E)

Installation

Using Arduino IDE

1. Download the latest release as a .zip file from the Releases page.
2. Open the Arduino IDE.
3. Go to Sketch > Include Library > Add .ZIP Library.
4. Select the downloaded .zip file and click Open.
5. The library will now be available under Sketch > Include Library > ML8511.

Manual Installation

1. Clone or download this repository.
2. Copy the folder containing ML8511.h and ML8511DEFS.h to your Arduino libraries folder:
   • Windows: Documents\Arduino\libraries\
   • macOS/Linux: ~/Documents/Arduino/libraries/
3. Restart the Arduino IDE.

Hardware Connections

• OUT Pin: Connect to an analog input pin on your microcontroller (e.g., A0).
• EN Pin: Connect to a digital output pin for enabling/disabling the sensor (e.g., D2).
• VCC: Connect to 3.3V (or as per your microcontroller's logic level).
• GND: Connect to ground.

Usage

Basic Example

#include <ML8511.h>

// Define pins
const uint8_t ANALOG_PIN = A0;
const uint8_t ENABLE_PIN = 2;

// Create sensor object
ML8511 uvSensor(ANALOG_PIN, ENABLE_PIN);

void setup() {
  Serial.begin(9600);
  uvSensor.setActiveUnit(mW_Per_Sq_cm); // Set unit to mW/cm²
}

void loop() {
  float uvIntensity = uvSensor.getUVIntensity();
  uint8_t uvIndex = uvSensor.getUVIndex();
  
  Serial.print("UV Intensity: ");
  Serial.print(uvIntensity);
  Serial.println(" mW/cm²");
  Serial.print("UV Index: ");
  Serial.println(uvIndex);
  
  delay(1000);
}

Calibration Example

#include <ML8511.h>

ML8511 uvSensor(A0, 2);

void setup() {
  Serial.begin(9600);
  
  // Calibrate with custom voltage values
  if (uvSensor.calibrateSensor(0.9, 2.1, 2.8)) {
    Serial.println("Calibration successful!");
  } else {
    Serial.println("Calibration failed!");
  }
  
  uvSensor.setActiveUnit(W_Per_Sq_m); // Set unit to W/m²
}

void loop() {
  float uvIntensity = uvSensor.getUVIntensity();
  Serial.print("UV Intensity: ");
  Serial.print(uvIntensity);
  Serial.println(" W/m²");
  delay(1000);
}

Enable Logging

#include <ML8511.h>

ML8511 uvSensor(A0, 2);

void setup() {
  Serial.begin(9600);
  uvSensor.showLogs(true); // Enable serial logging
  uvSensor.setActiveUnit(MED); // Set unit to MED
}

void loop() {
  float uvIntensity = uvSensor.getUVIntensity();
  Serial.print("UV Intensity: ");
  Serial.print(uvIntensity);
  Serial.println(" MED");
  delay(1000);
}

API Reference

Constructor

• ML8511(uint8_t analog, uint8_t enable): Initializes the sensor with the analog and enable pins.

Methods

• float getUVIntensity(): Returns the UV intensity in the currently set unit.
• uint8_t getUVIndex(): Returns the calculated UV Index (0-11+).
• void set_V0(float v0): Sets the zero-UV voltage (default: 0.87V).
• void setOverSampling(uint8_t oss): Sets the over-sampling factor (options: ML8511_OSS_0, ML8511_OSS_1, ML8511_OSS_2, ML8511_OSS_3).
• bool calibrateSensor(float UV0_voltage, float UV10_voltage, float UV15_voltage): Calibrates the sensor with custom voltage values.
• void setActiveUnit(uint8_t unit): Sets the unit for UV intensity (e.g., mW_Per_Sq_cm, W_Per_Sq_m, MED).
• void showLogs(bool show): Enables or disables serial logging.

Supported Units

Constant	Description	String Representation
mW_Per_Sq_cm	Milliwatts per cm²	mW/cm2
W_Per_Sq_m	Watts per m²	W/m2
microW_Per_Sq_cm	Microwatts per cm²	μW/cm2
Joules_s_Per_Sq_m	Joules/s per m²	Js/m2
mJoules_s_Per_Sq_cm	Millijoules/s per cm²	mJs/cm2
Joules_s_Per_Sq_cm	Joules/s per cm²	Js/cm2
MED	Minimal Erythemal Dose	MED

Notes

• The default ADC resolution is 10-bit (0-1023), but it switches to 12-bit (0-4095) for ESP32, RP2040, STM32, and SAM3X8E platforms.
• Ensure the sensor is powered with a stable 3.3V supply for accurate readings.
• Calibration voltages should align with the sensor's characteristics for reliable results.

License

This library is released under the MIT License. See the LICENSE file for details.

Author

• Saurav Sajeev

Contributing

Contributions are welcome! Please submit a pull request or open an issue on the GitHub repository.