INA219 Shunt Module Erratic Readings PROBLEM SOLVED!

[costalegre]

I recently built an LCD Current Meter with a INA219 Shunt Module with a sketch from GitHub. INA219_WE/examples at master · wollewald/INA219_WE · GitHub

The CONTINUOUS MODE sketch works perfect with resistive loads, but the current reading jumps around when the load is an active circuit like my metal detector.

Can anyone sugest a way to smooth or average this current reading?
current_mA = ina219.getCurrent_mA();
I tried the usual For Loop routine, EG: "for (int i = 0; i < avgSamples; i++)", but could not get that to work!!
Thanks, Mac VE7DEP

Now working with a Pro-Mini in LCD Case:

PROBLEM SOLVED! I did finally get the Averaging code to work.
int avgSamples = 2000; // Added for averaging
void loop() {
ina219.startSingleMeasurement();
for (int i = 0; i < avgSamples; i++) {
current_mA = current_mA + ina219.getCurrent_mA();
}
current_mA = current_mA / avgSamples;
Thanks Everyone. Mac VE7DEP

[paulpaulson]

Hello OM
take a look here to find a filter function.
73

[gilshultz]

It sounds like it is working just right and the load is constantly changing. You can always slow down your sample rate.

[costalegre]

@paulpaulson

filter function

You are correct gilshultz. The current is changing at the pulse rate of the detector's TX circuit even with a 4700uf buffer cap installed.

I did try delaying the readings, but even at 3 seconds if the display jumps up to an invalid reading, it stays displayed for the delay period which is irritating. It does display the correct reading most of the time.

[costalegre]

Thanks for the information Paul.
I think your Exponential Moving Average Algorithm would solve my problem but with my limited coding experience I'm not sure how to add it to the sketch.

void loop() {
  float shuntVoltage_mV = 0.0;
  float loadVoltage_V = 0.0;
  float busVoltage_V = 0.0;
  float current_mA = 0.0;
  float power_mW = 0.0;
  bool ina219_overflow = false;

  ina219.startSingleMeasurement(); // triggers single-shot measurement and waits until completed
  shuntVoltage_mV = ina219.getShuntVoltage_mV();
  busVoltage_V = ina219.getBusVoltage_V();
  current_mA = ina219.getCurrent_mA();
  power_mW = ina219.getBusPower();
  loadVoltage_V  = busVoltage_V + (shuntVoltage_mV / 1000);
  ina219_overflow = ina219.getOverflow();

  lcd.setCursor(1, 0);
  //lcd.print(current_mA);
  lcd.print(round(current_mA));  // Rounds off to whole number
  lcd.setCursor(6, 0);
  lcd.print(" MilliAmps  ");
  lcd.setCursor(0, 1);
  lcd.print(" MAX:1600mA +16V");
  delay(3000);  // New reading every 3 seconds.

Mac VE7DEP

YOUR EMA CODE:

//Global Variables

• int sensorPin = 0; //pin number to use the ADC*
• int sensorValue = 0; //initialization of sensor variable, equivalent to EMA Y*
• float EMA_a = 0.6; //initialization of EMA alpha*
• int EMA_S = 0; //initialization of EMA S*

void setup(){

• Serial.begin(115200); //setup of Serial module, 115200 bits/second*
• EMA_S = analogRead(sensorPin); //set EMA S for t=1*
  }

void loop(){

• sensorValue = analogRead(sensorPin); //read the sensor value using ADC*
• EMA_S = (EMA_a*sensorValue) + ((1-EMA_a)EMA_S); //run the EMA
• Serial.println(EMA_S); //print digital value to serial*
• delay(50); //50ms delay*
  }

[gilshultz]

Thanks for letting us know. Have a great fun filled year!