add comments

Lab_1/MotorEncoderAAR.ino

@@ -286,6 +286,7 @@ enum states get_current_state()
 // also speed impact probably doesn't matter much since setup() runs once per boot
 void initialiseEncoderStateMachine()
 {
+	// gets current state (initial) state and sets it
 	state = get_current_state();
 }
 
@@ -294,11 +295,12 @@ void updateEncoderStateMachine()
 {
 	enum states new_state = get_current_state(); // get new state, don't update state var yet so states can be compared
 
+	// check new state is valid, coming from state1, increment error count if not
+	// adjust count as appropriate if new state is valid
+	// repeat for all other state cases
 	switch (state)
 	{
 	case state1:
-		// check new state is valid, coming from state1, increment error count if not
-		// adjust count as appropriate if new state is valid
 		switch (new_state) {
 			case state1: break;
 			case state2: count++; break;

Lab_1/TestEncoderAAR.c

@@ -70,8 +70,12 @@ enum states get_current_state()
 }
 
 
+// doesn't have to be a fn anymore, but will be to maintain readability, expandability,
+// compatibility with setup() fn
+// also speed impact probably doesn't matter much since setup() runs once per boot
 void initialiseEncoderStateMachine()
 {
+	// gets current state (initial) state and sets it
 	state = get_current_state();
 }
 
@@ -80,11 +84,12 @@ void updateEncoderStateMachine()
 {
 	enum states new_state = get_current_state(); // get new state, don't update state yet so states can be compared
 
+	// check new state is valid, coming from state1, increment error count if not
+	// adjust count as appropriate if new state is valid
+	// repeat for all other state cases
 	switch (state)
 	{
 	case state1:
-		// check new state is valid, coming from state1, increment error count if not
-		// adjust count as appropriate if new state is valid
 		switch (new_state) {
 			case state1: break;
 			case state2: count++; break;

Lab_1/TwoSensorsAAR.c

@@ -9,8 +9,8 @@ float NISTmilliVoltsToDegCKtype(float tcEMFmV);  // returns temp in degC assumin
 
 float adc_to_voltage(float v_ref, int n_adc);
 float kelvin_to_c(float k);
-float resistance_to_temperature(float r);
-float voltage_to_resistance(float v);
+float resistance_to_thermistor_temperature(float r);
+float voltage_to_thermistor_resistance(float v);
 float voltage_to_erc(float v);
 
 int main()
@@ -23,12 +23,12 @@ int main()
 	scanf("%d %d", &thermistor_val, &thermocouple_val);
 
 	// Calculate thermistor temperature in degrees C ( Part b, i,ii,iii & v)
-	thermistor_temp = kelvin_to_c(resistance_to_temperature(voltage_to_resistance(adc_to_voltage(v_ref, thermistor_val))));
+	thermistor_temp = kelvin_to_c(resistance_to_thermistor_temperature(voltage_to_thermistor_resistance(adc_to_voltage(v_ref, thermistor_val))));
 
 	// Calculate thermocouple temperature in degrees C ( Part c, i - iv)
 	e_rc = 1000*voltage_to_erc(adc_to_voltage(v_ref, thermocouple_val)); // convert to millivolts
-	e_comp = NISTdegCtoMilliVoltsKtype(thermistor_temp);
-	thermocouple_temp = NISTmilliVoltsToDegCKtype(e_rc + e_comp);
+	e_comp = NISTdegCtoMilliVoltsKtype(thermistor_temp); // eqn (6) lab prep sheet
+	thermocouple_temp = NISTmilliVoltsToDegCKtype(e_rc + e_comp); // eqn (7) lab prep sheet
 
 
 	// Output results
@@ -42,7 +42,7 @@ int main()
 /* Write a function here to convert ADC value to voltages. (Part a, equation 1)
 Call it from the main() function above */
 float adc_to_voltage(float v_ref, int n_adc) {
-	return (float)n_adc*v_ref/1024.0;
+	return (float)n_adc*v_ref/1024.0; // eqn (1) lab prep sheet
 }
 
 
@@ -54,23 +54,29 @@ float kelvin_to_c(float k) {
 }
 
 
-float resistance_to_temperature(float r) {
+// Convert Resistance (Ohms) to Temperature (Kelvin) (for thermistor)
+float resistance_to_thermistor_temperature(float r) {
 	// Define Thermistor constants
-	float t_0 = 298.15;
-	float r_0 = 10000;
-	float b = 3975;
+	float t_0 = 298.15; // Kelvin
+	float r_0 = 10000; // Ohms
+	float b = 3975; // Kelvin
 
-	return 1.0 / ( (1.0/t_0) + (1.0/b)*log(r/r_0));
+	return 1.0 / ( (1.0/t_0) + (1.0/b)*log(r/r_0)); // eqn (3) lab prep sheet
 }
 
 
-float voltage_to_resistance(float v) {
-	return 1000*((10.0*3.3/v)-10.0);
+// Convert Voltage (Volts) to Resistance (Ohms)
+float voltage_to_thermistor_resistance(float v) {
+	float pull_down_resistance = 10; // kOhms
+	float v_hi = 3.3; // Volts
+
+	return 1000*((pull_down_resistance*v_hi/v)-10.0); // eqn (4) lab prep sheet
 }
 
 
+// Convert Voltage to E_RC
 float voltage_to_erc(float v) {
-	return (v-0.35)/54.4;
+	return (v-0.35)/54.4; // eqn (5) lab prep sheet
 }
 
 

Lab_1/TwoSensorsAAR.ino

@@ -17,7 +17,7 @@
 float adc_to_voltage(int n_adc);
 float kelvin_to_c(float k);
 float resistance_to_temperature(float r);
-float voltage_to_resistance(float v);
+float voltage_to_thermistor_resistance(float v);
 float voltage_to_erc(float v);
 
 void setup() 
@@ -34,12 +34,12 @@ void loop()
 	thermistor_val = analogRead(ThermistorPin);
 	thermocouple_val = analogRead(TCpin)
 	// Calculate thermistor temperature in degrees C ( Part b, i,ii,iii & v)
-	thermistor_temp = kelvin_to_c(resistance_to_temperature(voltage_to_resistance(adc_to_voltage(thermistor_val))));
+	thermistor_temp = kelvin_to_c(resistance_to_temperature(voltage_to_thermistor_resistance(adc_to_voltage(thermistor_val))));
 
 	// Calculate thermocouple temperature in degrees C ( Part c, i - iv)
 	e_rc = 1000*voltage_to_erc(adc_to_voltage(thermocouple_val)); // convert to millivolts
-	e_comp = NISTdegCtoMilliVoltsKtype(thermistor_temp);
-	thermocouple_temp = NISTmilliVoltsToDegCKtype(e_rc + e_comp);
+	e_comp = NISTdegCtoMilliVoltsKtype(thermistor_temp); // eqn (6) lab prep sheet
+	thermocouple_temp = NISTmilliVoltsToDegCKtype(e_rc + e_comp); // eqn (7) lab prep sheet
 
 	/* Display results.  Don't use printf or formatting etc., they don't work on the Arduino. Just use 
 	   the serial print statements given here, inserting your own code as needed */
@@ -55,7 +55,7 @@ void loop()
 /* Write a function to convert ADC value to 
    voltage: put it here and use it in your code above*/
 float adc_to_voltage(int n_adc) {
-	return (float)n_adc*V_REF/1024.0;
+	return (float)n_adc*V_REF/1024.0; // eqn (1) lab prep sheet
 }
 
 
@@ -66,23 +66,29 @@ float kelvin_to_c(float k) {
 }
 
 
-float resistance_to_temperature(float r) {
+// Convert Resistance (Ohms) to Temperature (Kelvin) (for thermistor)
+float resistance_to_thermistor_temperature(float r) {
 	// Define Thermistor constants
-	float t_0 = 298.15;
-	float r_0 = 10000;
-	float b = 3975;
+	float t_0 = 298.15; // Kelvin
+	float r_0 = 10000; // Ohms
+	float b = 3975; // Kelvin
 
-	return 1.0 / ( (1.0/t_0) + (1.0/b)*log(r/r_0));
+	return 1.0 / ( (1.0/t_0) + (1.0/b)*log(r/r_0)); // eqn (3) lab prep sheet
 }
 
 
-float voltage_to_resistance(float v) {
-	return 1000*((10.0*3.3/v)-10.0);
+// Convert Voltage (Volts) to Resistance (Ohms)
+float voltage_to_thermistor_resistance(float v) {
+	float pull_down_resistance = 10; // kOhms
+	float v_hi = 3.3; // Volts
+
+	return 1000*((pull_down_resistance*v_hi/v)-10.0); // eqn (4) lab prep sheet
 }
 
 
+// Convert Voltage to E_RC
 float voltage_to_erc(float v) {
-	return (v-0.35)/54.4;
+	return (v-0.35)/54.4; // eqn (5) lab prep sheet
 }