computing trip statistics on ESP32 (distance, time, elevation, etc.)

ESP32/src/utils.cpp

@@ -18,4 +18,19 @@ namespace utils
 			return (biggestValue - from) + to + 1;
 		}
 	}
+
+	uint32_t elapsed(uint32_t from, uint32_t to)
+	{
+		if(to >= from)
+		{
+			return to - from;
+		}
+		else
+		{
+			// if the counter overflowed, this computes the real duration
+			// of course it won't work if the counter made a "full turn" or more
+			const uint32_t biggestValue = (uint32_t)-1;
+			return (biggestValue - from) + to + 1;
+		}
+	}
 }

ESP32/src/vehicle-monitor.cpp

@@ -33,12 +33,20 @@ const int8_t I2C_SCL = 4;
 const float wheelDiameterInches = 20;
 const int numImpulsesPerTurn = 2;
 const float wheelCircumferenceMeters = wheelDiameterInches * 0.0254f * 3.1415f / (float)numImpulsesPerTurn;
+const uint32_t wheelCircumferenceMillimeters = (uint32_t)(wheelCircumferenceMeters * 1000.0f + 0.5f);
 
 uint16_t batteryVoltage = 0; // in mV
 uint16_t batteryOutputCurrent = 0; // in mV
 int16_t temperature = 0; // in tenth of °C
 int32_t altitude = 0; // in mm above sea level (can be negative if below sea level, or depending on atmospheric conditions)
 
+// current trip
+uint32_t tripDistance = 0; // in meters
+uint16_t tripMovingTime = 0; // cumulated seconds, only when moving at non-zero speed
+uint16_t tripTotalTime = 0; // total trip time in seconds
+uint32_t tripAscendingElevation = 0; // cumulated ascending elevation, in millimeters
+uint32_t tripMotorEnergy = 0; // in Joules
+
 WiFiMulti wifiMulti;
 wl_status_t wifi_STA_status = WL_NO_SHIELD;
 unsigned long wifiConnexionBegin = 0;
@@ -52,6 +60,7 @@ volatile bool speedSensorState = false;
 volatile unsigned long speedSensorRiseTime = 0;
 volatile unsigned long speedSensorLastImpulseTime = 0;
 volatile unsigned long speedSensorLastImpulseInterval = (unsigned long)-1; // in milliseconds
+volatile uint32_t speedSensorDistance = 0; // Cumulated measured distance, in millimeters. This value will overflow after about 4000km.
 void IRAM_ATTR onSpeedSensorChange(bool newState)
 {
 	if(speedSensorState == newState) return;
@@ -78,16 +87,21 @@ void IRAM_ATTR onSpeedSensorChange(bool newState)
 		{
 			// too little time between impulses, probably some bouncing, ignore it
 		}
-		else if(timeSinceLastImpulse < 4000)
-		{
-			speedSensorLastImpulseTime = now;
-			speedSensorLastImpulseInterval = timeSinceLastImpulse;
-		}
 		else
 		{
-			// too much time between impulses, can't compute speed from that
-			speedSensorLastImpulseTime = now;
-			speedSensorLastImpulseInterval = (unsigned long)-1;
+			speedSensorDistance += wheelCircumferenceMillimeters;
+
+			if(timeSinceLastImpulse < 4000)
+			{
+				speedSensorLastImpulseTime = now;
+				speedSensorLastImpulseInterval = timeSinceLastImpulse;
+			}
+			else
+			{
+				// too much time between impulses, can't compute speed from that
+				speedSensorLastImpulseTime = now;
+				speedSensorLastImpulseInterval = (unsigned long)-1;
+			}
 		}
 	}
 }
@@ -200,17 +214,23 @@ void setup()
 		int v = batteryVoltage;
 		int c = batteryOutputCurrent;
 		int s = (int)(getSpeed() * 1000.0f + 0.5f);
-		int t = temperature;
+		int temp = temperature;
 		int alt = altitude;
 
+		int td = tripDistance;
+		int ttt = tripTotalTime;
+		int tmt = tripMovingTime;
+		int tae = tripAscendingElevation / 100; // convert mm to dm
+		int tme = tripMotorEnergy / 360; // convert Joules to dWh (tenth of Wh)
+
 		const char* logFileName = DataLogger::get().currentLogFileName();
 		if(String(logFileName).startsWith("/log/")) logFileName += 5;
 
 		int totalSize = (int)(SPIFFS.totalBytes() / 1000);
 		int usedSize = (int)(SPIFFS.usedBytes() / 1000);
 
-		char json[128];
-		sprintf(json, "{\"v\":%d,\"c\":%d,\"s\":%d,\"t\":%d,\"alt\":%d,\"log\":\"%s\",\"tot\":%d,\"used\":%d}", v, c, s, t, alt, logFileName, totalSize, usedSize);
+		char json[256];
+		sprintf(json, "{\"v\":%d,\"c\":%d,\"s\":%d,\"td\":%d,\"ttt\":%d,\"tmt\":%d,\"tae\":%d,\"tme\":%d,\"temp\":%d,\"alt\":%d,\"log\":\"%s\",\"tot\":%d,\"used\":%d}", v, c, s, td, ttt, tmt, tae, tme, temp, alt, logFileName, totalSize, usedSize);
 		request->send(200, "text/json", json);
 	});
 
@@ -399,6 +419,10 @@ void loop()
 	handle_pressure_measure(); // also measures temperature
 
 	unsigned long now = millis();
+	static unsigned long lastLoopMillis = now;
+	unsigned long dt = utils::elapsed(lastLoopMillis, now);
+	lastLoopMillis = now;
+
 	static DataLogger::Entry entry;
 	entry.batteryVoltage = (float)batteryVoltage / 1000.0f;
 	entry.batteryOutputCurrent = (float)batteryOutputCurrent / 1000.0f;
@@ -413,6 +437,11 @@ void loop()
 		{
 			DebugLog.println("Starting DataLogger");
 			DataLogger::get().open();
+			tripDistance = 0;
+			tripMovingTime = 0;
+			tripTotalTime = 0;
+			tripAscendingElevation = 0;
+			tripMotorEnergy = 0;
 		}
 	}
 	else
@@ -432,5 +461,41 @@ void loop()
 	}
 	DataLogger::get().log(now, entry);
 
-	delay(DataLogger::get().isOpen() ? 10 : 1000);
+	bool isOnTrip = DataLogger::get().isOpen();
+	bool isMoving = entry.speed > 0.0f;
+
+	static unsigned long cumulatedMillis = 0;
+	cumulatedMillis += dt;
+	unsigned long newSeconds = cumulatedMillis / 1000;
+	cumulatedMillis -= newSeconds * 1000;
+
+	uint32_t currentMillimeters = speedSensorDistance;
+	static uint32_t lastLoopMillimeters = currentMillimeters;
+	uint32_t newMillimeters = utils::elapsed(lastLoopMillimeters, currentMillimeters);
+	lastLoopMillimeters = currentMillimeters;
+
+	static uint32_t cumulatedMillimeters = 0;
+	cumulatedMillimeters += newMillimeters;
+	uint32_t newMeters = cumulatedMillimeters / 1000;
+	cumulatedMillimeters -= newMeters * 1000;
+
+	uint32_t altitudeMillimeters = (uint32_t)(entry.altitude * 1000.0f + 0.5f);
+	static uint32_t lastLoopAltitude = altitudeMillimeters;
+	uint32_t altitudeChange = altitudeMillimeters - lastLoopAltitude;
+	lastLoopAltitude = altitudeMillimeters;
+
+	if(isOnTrip)
+	{
+		tripTotalTime += newSeconds;
+		if(isMoving) tripMovingTime += newSeconds;
+		tripDistance += newMeters;
+
+		if(altitudeChange > 0)
+			tripAscendingElevation += altitudeChange;
+
+		uint32_t newEnergy = entry.batteryVoltage * entry.batteryOutputCurrent * ((float)dt / 1000.0f);
+		tripMotorEnergy += newEnergy;
+	}
+
+	delay(isOnTrip ? 10 : 1000);
 }

WebApp/src/monitor-api.ts

@@ -4,16 +4,26 @@ export interface Status {
 	batteryVoltage: number; // in Volts
 	motorCurrent: number; // in Amperes
 	speed: number; // in meters per second
+	tripDistance: number; // in meters
+	tripTotalTime: number; // in seconds
+	tripMovingTime: number; // in seconds
+	tripAscendingElevation: number; // in meters
+	tripMotorEnergy: number; // in Watt-hour
 	temperature: number; // in Celcius degrees
 	altitude: number; // in meters above sea level
 };
 
 interface ApiStatus {
-	v: number;
-	c: number;
-	s: number;
-	t: number;
-	alt: number;
+	v: number; // voltage (mV)
+	c: number; // current (mA)
+	s: number; // speed (mm/s)
+	td: number; // trip distance (m)
+	ttt: number; // trip total time (s)
+	tmt: number; // trip moving time (s)
+	tae: number; // trip ascending elevation (m)
+	tme: number; // trip motor energy (Wh)
+	temp: number; // temperature (tenth of °C)
+	alt: number; // altitude (mm)
 }
 
 export class MonitorApi {
@@ -21,6 +31,15 @@ export class MonitorApi {
 	private lastStatus: Status = null;
 	private static api: MonitorApi = null;
 	
+	private lastFetchTime = 0;
+	private lastFetchAltitude = -100000;
+	
+	private mockedTripDistance = 0;
+	private mockedTripTotalTime = 0;
+	private mockedTripMovingTime = 0;
+	private mockedTripAscendingElevation = 0;
+	private mockedTripMotorEnergy = 0;
+	
 	constructor() {
 		this.mockServer = window.location.protocol == "file:";
 	}
@@ -39,13 +58,43 @@ export class MonitorApi {
 		if(this.mockServer) {
 			await new Promise(resolve => setTimeout(resolve, 200));
 			
-			let t = new Date().getTime() / 1000.0;
+			let t = Date.now() / 1000.0;
+			if(this.lastFetchTime == 0) this.lastFetchTime = t;
+			let dt = t - this.lastFetchTime;
+			this.lastFetchTime = t;
+			
+			let speed = (Math.cos(t*0.3)+1.0)*0.5 * 14; // in meters per second
+			if(speed < 0.25) speed = 0;
+			
+			this.mockedTripDistance += speed * dt;
+			this.mockedTripTotalTime += dt;
+			if(speed > 0)
+				this.mockedTripMovingTime += dt;
+			
+			let altitude = (Math.cos(t*0.0001)+1.0)*0.5 * 4500 - 200 + (Math.cos(t*0.03))*0.5 * 60; // in meters
+			if(this.lastFetchAltitude == -100000) this.lastFetchAltitude = altitude;
+			let altitudeChange = altitude - this.lastFetchAltitude;
+			this.lastFetchAltitude = altitude;
+			
+			if(altitudeChange > 0)
+				this.mockedTripAscendingElevation += altitudeChange;
+				
+			let voltage = (Math.cos(t*0.4)+1.0)*0.5 * 6 + 36;
+			let current = (Math.cos(t*0.7)+1.0)*0.5 * 30;
+			let newEnergy = voltage * current * dt / 3600;
+			this.mockedTripMotorEnergy += newEnergy;
+			
 			apiStatus = {
-				v: (Math.cos(t*0.4)+1.0)*0.5 * 6000 + 36000,
-				c: (Math.cos(t*0.7)+1.0)*0.5 * 30000,
-				s: (Math.cos(t*0.3)+1.0)*0.5 * 14000,
-				t: (Math.cos(t*0.2)+1.0)*0.5 * 400 - 100,
-				alt: (Math.cos(t*0.0001)+1.0)*0.5 * 4500000 - 200000 + (Math.cos(t*0.03))*0.5 * 60000
+				v: Math.round(voltage * 1000),
+				c: Math.round(current * 1000),
+				s: Math.round(speed * 1000),
+				td: Math.round(this.mockedTripDistance),
+				ttt: Math.round(this.mockedTripTotalTime),
+				tmt: Math.round(this.mockedTripMovingTime),
+				tae: Math.round(this.mockedTripAscendingElevation*10.0),
+				tme: Math.round(this.mockedTripMotorEnergy*10.0),
+				temp: Math.round((Math.cos(t*0.2)+1.0)*0.5 * 400 - 100),
+				alt: Math.round(altitude * 1000)
 			};
 		} else {
 			apiStatus = await new Promise<ApiStatus>((resolve, error) => {
@@ -69,7 +118,12 @@ export class MonitorApi {
 			batteryVoltage: apiStatus.v / 1000,
 			motorCurrent: apiStatus.c / 1000,
 			speed: apiStatus.s / 1000,
-			temperature: apiStatus.t / 10,
+			tripDistance: apiStatus.td,
+			tripTotalTime: apiStatus.ttt,
+			tripMovingTime: apiStatus.tmt,
+			tripAscendingElevation: apiStatus.tae / 10,
+			tripMotorEnergy: apiStatus.tme / 10,
+			temperature: apiStatus.temp / 10,
 			altitude: apiStatus.alt / 1000
 		};
 		

WebApp/src/pages/dashboard/dashboard-page.tsx

@@ -19,14 +19,12 @@ export class DashboardPage extends Page {
 	private battery = new Pipe(0.0);
 	private speed = new Pipe(0.0);
 	
-	private lastRefreshTime = 0.0;
-	private movementTime = 0.0;
-	private distance = new Pipe(0.0);
-	private averageSpeed = new Pipe(0.0);
-	private energy = new Pipe(0.0);
-	private averageConsumption = new Pipe(0.0);
-	private ascendingElevation = new Pipe(0.0);
-	private lastElevation = -100000;
+	private tripDistance = new Pipe(0.0);
+	private tripAverageSpeed = new Pipe(0.0);
+	private tripEnergy = new Pipe(0.0);
+	private tripAverageConsumption = new Pipe(0.0);
+	private tripAscendingElevation = new Pipe(0.0);
+	
 	private altitude = new Pipe(0.0);
 	private temperature = new Pipe(0.0);
 	
@@ -55,30 +53,14 @@ export class DashboardPage extends Page {
 		
 		this.speed.set(this.status.speed * 3.6); // convert m/s to km/h
 		
-		let now = Date.now() / 1000;
-		if(this.lastRefreshTime == 0.0) this.lastRefreshTime = now;
-		let dt = now - this.lastRefreshTime;
-		this.lastRefreshTime = now;
-		
-		if(this.status.speed > 0.0)
-			this.movementTime += dt;
-		this.distance.set(this.distance.get() + this.status.speed * dt / 1000);
-		if(this.movementTime > 0.0)
-			this.averageSpeed.set(this.distance.get() / (this.movementTime / 3600));
+		this.tripDistance.set(this.status.tripDistance/1000);
+		this.tripAverageSpeed.set(this.status.tripDistance/1000 / (Math.max(1.0, this.status.tripMovingTime)/3600));
+		this.tripEnergy.set(this.status.tripMotorEnergy);
+		this.tripAverageConsumption.set(this.status.tripMotorEnergy / Math.max(0.1, this.status.tripDistance/1000));
+		this.tripAscendingElevation.set(this.status.tripAscendingElevation);
 			
-		if(this.lastElevation == -100000)
-			this.lastElevation = this.status.altitude;
-		let elevationChange = this.status.altitude - this.lastElevation;
-		this.lastElevation = this.status.altitude;
-		if(elevationChange > 0.0)
-			this.ascendingElevation.set(this.ascendingElevation.get() + elevationChange);
-		this.altitude.set(this.status.altitude);
-		
 		this.temperature.set(this.status.temperature);
-		
-		this.energy.set(this.energy.get() + power * dt / 3600);
-		if(this.distance.get() > 0.1)
-			this.averageConsumption.set(this.energy.get() / this.distance.get());
+		this.altitude.set(this.status.altitude);
 		
 		if(this.autoRefresh)
 			setTimeout(() => { if(this.autoRefresh) this.refresh(); }, 150);
@@ -98,15 +80,15 @@ export class DashboardPage extends Page {
 				</div>
 				
 				<div class="widgets-row">
-					<NumericValue widgetWidth={0.5} value={this.distance} decimals={1} unit="km" />
+					<NumericValue widgetWidth={0.5} value={this.tripDistance} decimals={1} unit="km" />
 				</div>
 				<div class="widgets-row">
-					<NumericValue widgetWidth={0.5} value={this.averageSpeed} decimals={1} unit="km/h" />
-					<NumericValue widgetWidth={0.5} value={this.ascendingElevation} decimals={1} unit="m" />
+					<NumericValue widgetWidth={0.5} value={this.tripAverageSpeed} decimals={1} unit="km/h" />
+					<NumericValue widgetWidth={0.5} value={this.tripAscendingElevation} decimals={1} unit="m" />
 				</div>
 				<div class="widgets-row">
-					<NumericValue widgetWidth={0.5} value={this.averageConsumption} decimals={1} unit="Wh/km" />
-					<NumericValue widgetWidth={0.5} value={this.energy} decimals={1} unit="Wh" />
+					<NumericValue widgetWidth={0.5} value={this.tripAverageConsumption} decimals={1} unit="Wh/km" />
+					<NumericValue widgetWidth={0.5} value={this.tripEnergy} decimals={1} unit="Wh" />
 				</div>
 				
 				<div class="widgets-row">