added ADC calibration code

ESP32/vehicle-monitor.cpp

@@ -9,8 +9,44 @@
 
 AsyncWebServer server(80);
 
+float averageBatteryVoltage = 0.0f;
 int16_t batteryVoltage = -1; //in mV
 
+struct ADC_CalibrationValue
+{
+	float Measure;
+	int16_t ADC_Value;
+};
+
+const ADC_CalibrationValue calibration[] = {
+	{ 0.118f,	1 },
+	{ 0.343f, 	253 },
+	{ 0.791f, 	801 },
+	{ 1.512f, 	1705 },
+	{ 2.013f,	2306 },
+	{ 2.406f,	2796 },
+	{ 2.606f,	3058 },
+	{ 2.839f,	3423 },
+	{ 2.996f,	3726 },
+	{ 3.16f,	4094 }
+};
+const int8_t calibrationNumValues = sizeof(calibration)/sizeof(calibration[0]);
+
+float getCalibratedVoltage(int16_t adcOutput)
+{
+	for(int8_t i = 1; i < calibrationNumValues; ++i)
+	{
+		if(i == calibrationNumValues - 1 || calibration[i].ADC_Value >= adcOutput)
+		{
+			const auto& p = calibration[i - 1];
+			const auto& n = calibration[i];
+			return (float)(adcOutput - p.ADC_Value) / (float)(n.ADC_Value - p.ADC_Value) * (n.Measure - p.Measure) + p.Measure;
+		}
+	}
+
+	return -1.0f;
+}
+
 void setup()
 {
 	Serial.begin(115200);
@@ -50,13 +86,22 @@ void setup()
 	Serial.println("HTTP server started");
 }
 
+float avgAnalogV = 0.0f;
+
 void loop()
 {
 	const int potPin = 34;
 
-	delay(1000);
+	const float minV = 0.14f; // 1
+	const float maxV = 3.16f; // 4094
+
+	delay(10);
 	int16_t analogV = analogRead(potPin);
-	float v = (float)analogV / 4096.0f * 3.3f;
+	float v = getCalibratedVoltage(analogV);
-	batteryVoltage = (int16_t)(v * 1000.0f + 0.5f);
+
-	//Serial.println(potValue);
+	averageBatteryVoltage = averageBatteryVoltage * 0.95f + v * 0.05f;
+	batteryVoltage = (int16_t)(averageBatteryVoltage * 1000.0f + 0.5f);
+
+	//avgAnalogV = avgAnalogV * 0.9f + (float)analogV * 0.1f;
+	//batteryVoltage = (int16_t)(avgAnalogV + 0.5f);
 }

WebApp/src/main-page.tsx

@@ -23,8 +23,8 @@ export default class MainPage {
 	view() {
 		return this.status
 			? <div>
-				<p>Tension batterie : {this.status.batteryVoltage.toFixed(1)}V</p>
+				<p>Tension batterie : {this.status.batteryVoltage.toFixed(3)}V</p>
-				<p>Courant : {this.status.motorCurrent.toFixed(1)}A</p>
+				<p>Courant : {this.status.motorCurrent.toFixed(3)}A</p>
 				<p>Puissance : {(this.status.batteryVoltage * this.status.motorCurrent).toFixed(1)}W</p>
 			</div>
 			: <p>Chargement...</p>;