56 lines
1.2 KiB
C++
56 lines
1.2 KiB
C++
// FILE: RMS_by_sampling.ino
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// AUTHOR: Rob Tillaart
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// DATE: 2022-08-15
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// PURPOSE: demo RMS by sampling for AC current
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// URL: https://github.com/RobTillaart/ACS712
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//
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// stand alone sketch to be used with a ACS712
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#include "Arduino.h"
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// #include "printHelpers.h"
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void setup()
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{
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Serial.begin(115200);
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while (!Serial);
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Serial.println(__FILE__);
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}
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void loop()
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{
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// 50 Hz, Arduino UNO, 20A ACS
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float current = mA_AC_sampling(50, 5000.0 / 1023, 100, A0);
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Serial.println(current);
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delay(1000);
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}
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float mA_AC_sampling(float frequency, float mVperStep, float mVperAmpere, uint8_t analogPin)
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{
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uint16_t midpoint = 511;
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uint32_t period = round(1000000UL / frequency);
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uint16_t samples = 0;
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float sumSquared = 0;
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uint32_t start = micros();
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while (micros() - start < period)
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{
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samples++;
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float current = analogRead(analogPin) - midpoint;
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sumSquared += (current * current);
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}
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// Serial.print(scieng(sumSquared, 1, 3));
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// Serial.print("\t");
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// Serial.print(samples);
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// Serial.print("\t");
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float AmperePerStep = mVperStep / mVperAmpere;
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float RMS = sqrt(sumSquared / samples) * AmperePerStep;
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return RMS * 1000.0; // mA
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}
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// -- END OF FILE --
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