[材料]

1. Arduino UNO主板 x 1

2. TSL237S-LF 高敏感度光-頻率轉換器(high-sensitivity light-to-frequency converter)  x 1

3. 電容0.1uF  x 1

/* Example: TSL237-LF

  TSL237     Arduino pins

  GND        GND

  Vcc        +5V

  Out        Digital pin 2

  Wire a 0.1uF capacitator between Vcc and GND close to the sensor

*/

// Pin definitions

# define TSL237 2                      // Out of TSL237 connected to Digital pin 2

// Constants

int period = 1000;                     // Miliseconds of each light frecuency measurement

int ScalingFactor = 0.1;               // Scaling factor of this sensor

float area = 0.0092;                   // Sensing area of TSL237 device (cm2)

float millsec01,millsec02;

// Variables

unsigned long counter = 0;             // Counter of measurements during the test

unsigned long currentTime = millis();  

unsigned long startTime = currentTime; 

volatile long pulses = 0;              // Counter of measurements of the TSL237

unsigned long frequency;               // Read the frequency from the digital pin (pulses/second)

float irradiance;                      // Calculated irradiance (uW/cm2)

void setup() {

 Serial.begin(9600);                           // Start and configure the serial port

 attachInterrupt(0, PulseCount, RISING);

 pinMode(TSL237, INPUT);                       // Declare the pin such as an input of data

 Serial.println("Testing a TSL237 sensor:");   // Splash screen

 Serial.println("-------------------------");

 Serial.println();  

}

void loop(){

 millsec01=millis();

 getfrequency();                      // Request to measure the frequency

 getirradiance();                     // Request to calculate the irradiance (uW/cm2)

 Serial.print("  ");

 Serial.print(irradiance);            // print the frequency (pulses/second)

 Serial.println(" uW/cm2");

 pulses = 0;                          // reset the pulses counter

 millsec02=millis();

 delay (2000);

}

void PulseCount()

{

pulses++;

}

unsigned long getfrequency () {

 noInterrupts();

 frequency = pulses /((millsec01- millsec02)/1000);   // Calculate the frequency (pulses/second)

 interrupts();

 return (frequency);

}

float getirradiance () {

 irradiance = frequency / area;       // Calculate Irradiance (uW/cm2)

 return (irradiance);

}

[實驗步驟]

1.  數值最大可達到多少？

參考資料：

1. 程式碼與應用：https://www.uni-weimar.de/kunst-und-gestaltung/wiki/GMU:Connecting_Max_to_the_World/Frederic_Blais-Belanger/Sensoring_Pyrocystis_light 

2. TSL237S-LF datasheet：https://www.jameco.com/Jameco/Products/ProdDS/2151435.pdf 

/*

  Sky Quality Meter

  Sensor: TSL237S-LF

  Board: Arduino UNO R4 WiFi

*/

// Pin definitions

#define TSL237 2

// Constants

const unsigned long period = 1000;  // Measurement period (ms)

float ScalingFactor = 0.1;  // 保留原始設定

float area = 0.0092;        // Sensing area (cm2)

// Variables

volatile unsigned long pulses = 0;

unsigned long frequency = 0;

float irradiance = 0;

// Interrupt service routine

void PulseCount() {

  pulses++;

}

void setup() {

  Serial.begin(9600);

  pinMode(TSL237, INPUT);

  attachInterrupt(

    digitalPinToInterrupt(TSL237),

    PulseCount,

    RISING

  );

  Serial.println("Testing a TSL237 sensor:");

  Serial.println("-------------------------");

  Serial.println();

}

void loop() {

  // 開始計時

  unsigned long startTime = millis();

  // 等待完整的測量時間

  while (millis() - startTime < period) {

    // 等待脈波累積

  }

  // 計算實際經過時間

  unsigned long endTime = millis();

  unsigned long elapsedTime = endTime - startTime;

  // 安全讀取並清除脈波計數

  noInterrupts();

  unsigned long pulseCount = pulses;

  pulses = 0;

  interrupts();

  // 計算頻率（pulses/second）

  frequency = pulseCount * 1000UL / elapsedTime;

  // 計算輻照度（保留原始公式）

  getirradiance();

  // 輸出結果

  Serial.print(irradiance);

  Serial.println(" uW/cm2");

}

// Calculate irradiance

float getirradiance() {

  irradiance = (float)frequency / area;

  return irradiance;

}