如何读取电流传感器与arduino？

以HSTS016L型号为例，它能够测量10A到200A的电流值。使用分芯电流传感器类型，我们可以在不改变现有系统的情况下打开和关闭CT，只需使用夹子将测量电缆放入CT内部。该传感器的输出电压为2.5V +/- 0.625V，具有良好的精度。虽然该传感器的电压输出范围在1.875V到3.125V之间，但它也适用于3.3V的模拟传感器，特别是Arduino Nano和NodeMCU微控制器。

传感器有4个输出引脚：红色（5V输入），黑色（0V Gnd），黄色（模拟输出）和白色（校准模拟）。有时电源电压可能不是精确的5V，因此我们需要额外的模拟引脚来测量白引脚的确切中点。对于Arduino UNO，有6个模拟输入引脚（A0-A5），我们可以使用其中一个引脚来测量交流电流，另外一个引脚用于校准目的。模拟输入引脚将0到5V之间的输入电压映射为0到1023之间的整数值，分辨率为4.9mV /单位（5.00V / 1023单位）。

我们将红色连接到5V输入，黑色连接到地，黄色连接到模拟引脚A1，白色连接到模拟引脚A2。强烈建议使用12V电源适配器为Arduino Uno和传感器供电。通过USB使用5V电源会有一个初始偏移值，您可能需要在上传代码时手动添加偏移值。

// Which pin to measure Current Value (A0 is reserved for LCD Display Shield Button function)

int currentAnalogInputPin = A1;  

// Which pin to calibrate offset middle value

int calibrationPin = A2; 

// Key in value to manually offset the initial value

float manualOffset = 0.00;

// If using “Hall-Effect” Current Transformer, key in value using this formula: mVperAmp = maximum voltage range (in milli volt) / current rating of CT

float mVperAmpValue = 12.5;        

// Analog input pin maximum supply voltage, Arduino Uno or Mega is 5000mV while Arduino Nano or Node MCU is 3300mV

float supplyVoltage = 5000;

/* to read the value of a sample for offset purpose later */

float offsetSampleRead = 0;        

 /* to read the value of a sample including currentOffset1 value*/

float currentSampleRead  = 0;     

  /* to count time for each sample. Technically 1 milli second 1 sample is taken */

float currentLastSample  = 0;     

  /* accumulation of sample readings */

float currentSampleSum   = 0;     

  /* to count number of sample. */

float currentSampleCount = 0;     

    /* to calculate the average value from all samples, in analog values*/

float currentMean ;            

  /* square roof of currentMean, in analog values */

float RMSCurrentMean ;             

   /* the final RMS current reading*/

float FinalRMSCurrent ;           

void setup()                                 /*codes to run once */

{

        Serial.begin(9600);                 /* to display readings in Serial Monitor at 9600 baud rates */

}

void loop()

{

        /* 1- AC & DC Current Measurement */

        if(micros() >= currentLastSample + 200)                     /* every 0.2 milli second taking 1 reading */

          {

           /* read the sample value including offset value*/

           currentSampleRead = analogRead(currentAnalogInputPin)-analogRead(calibrationPin); 

          /* accumulate total analog values for each sample readings*/

           currentSampleSum = currentSampleSum + sq(currentSampleRead) ;

           /* to count and move on to the next following count */

           currentSampleCount = currentSampleCount + 1; 

           /* to reset the time again so that next cycle can start again*/

           currentLastSample = micros(); 

          }

        /* after 4000 count or 800 milli seconds (0.8 second), do this following codes*/

        if(currentSampleCount == 4000) 

          {

            /* average accumulated analog values*/

            currentMean = currentSampleSum/currentSampleCount;

             /* square root of the average value*/

            RMSCurrentMean = sqrt(currentMean);

             /* calculate the final RMS current*/

            FinalRMSCurrent = (((RMSCurrentMean /1023) *supplyVoltage) /mVperAmpValue)- manualOffset;

              /* if the current detected is less than or up to 1%, set current value to 0A*/

            if(FinalRMSCurrent <= (625/mVperAmpValue/100))

            { FinalRMSCurrent =0; }

            Serial.print(” The Current RMS value is: “);

            Serial.print(FinalRMSCurrent,decimalPrecision);

            Serial.println(” A “);

            currentSampleSum =0;                                 /* to reset accumulate sample values for the next cycle */

            currentSampleCount=0;                                 /* to reset number of sample for the next cycle */

          }

}