Distance_HC_SR04 Class Reference

Applied rules: 0, 1,.

Create Distance_HC_SR04 instance. Set FSM to IDLE state.

Definition at line 10 of file Distance_HC_SR04.cpp.

Return actual value of coefficient used to calculate distance from "echo" pulse duration.

Returns:

float Value of the coefficient used to multiply time in microseconds to get distance in mm.

Definition at line 155 of file Distance_HC_SR04.cpp.

Return distance of the obstacle.

Use in asynchronous non-blocking mode.

New measurement is not started. Uses result from last measurement.

Returns:

float Distance in milimiters calculated from measured duration of "echo" pulse.

Definition at line 145 of file Distance_HC_SR04.cpp.

Returns a state of measurement FSM in asynchronous non-blocking mode.

This function is used in asynchronous non-blocking mode.

Returns:

Distance_HC_SR04_state FSM state value.

Definition at line 121 of file Distance_HC_SR04.cpp.

Return measured duration of "echo" pulse in "COMPLETED" state.

Use in asynchronous non-blocking mode.

New measurement is not started. Uses result from last measurement.

Returns:

uint32_t Measured duration of "echo" pulse in microseconds.

Definition at line 133 of file Distance_HC_SR04.cpp.

Measure (synchronous) distance of the object by reflected ultrasonic signal.

Measure and return the distance in synchronous blocking mode.

Measure the distance from the object by reflected ultrasonic signal in synchronous (blocking) mode. In case of any error, returns 0. Error information can be retrieved via getState() method.

Example of usage:

 Distance_HC_SR04 dist(PIN_TRIG, PIN_ECHO);
 float distance;

 while (true) {
     distance = dist.getDistance();
     lcd.cls();

     switch (dist.getState()) {
         case COMPLETED:
             lcd.printf("Dist.: %.3f", dist);
             lcd.locate(0, 1);
             lcd.printf("COMPLETED");

             break;

         case TIMEOUT:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("TIMEOUR");

             break;
         case ERROR_SIG:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("ERROR_SIG");

             break;

         case OUT_OF_RANGE_MIN:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OUT_OF_RANGE_MIN");

             break;

         case OUT_OF_RANGE_MAX:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OUT_OF_RANGE_MAX");

             break;

         default:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OTHER");

             break;
     }
     wait_ms(100);
 }

Parameters:

-

Returns:

Object distance in milimeters. 0 in case of error.

See also:

-

Note:

- Calculation can be influenced by changing _coeff via setCoeff() or Distance_HC_SR04().

Warning:

-

New measurement is started and the code waits for measurement completion or timeout.

Parameters:

void

-

Returns:

float value of distance > 0.0f in case of a success, 0.0f in case of an error

Definition at line 61 of file Distance_HC_SR04.cpp.

Measure (synchronous) ultrasonic signal travel time.

Measure and return "echo" pulse duration in synchronous blocking mode.

Measure the ultrasonic signal travel time in microseconds in synchronous (blocking) mode. In case of any error, returns 0. Error information can be retrieved via getState() method.

Example of usage:

 Distance_HC_SR04 dist(PIN_TRIG, PIN_ECHO);
 uint32_t ticks_us;

 while (true) {
     ticks_us = dist.measureTicks();
     lcd.cls();

     switch (dist.getState()) {
         case COMPLETED:
             lcd.printf("Dist.: %u", ticks_us);
             lcd.locate(0, 1);
             lcd.printf("COMPLETED");

             break;

         case TIMEOUT:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("TIMEOUR");

             break;
         case ERROR_SIG:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("ERROR_SIG");

             break;

         case OUT_OF_RANGE_MIN:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OUT_OF_RANGE_MIN");

             break;

         case OUT_OF_RANGE_MAX:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OUT_OF_RANGE_MAX");

             break;

         default:
             lcd.printf("Dist.: ---");
             lcd.locate(0, 1);
             lcd.printf("OTHER");

             break;
     }
     wait_ms(100);
 }

Parameters:

-

Returns:

Ultrasonic signal total travel time (including reflected signal) in microseconds. 0 in case of error.

See also:

-

Note:

-

Warning:

-

New measurement is started and the code waits for measurement completion or timeout.

Parameters:

void

-

Returns:

uint32_t value of distance > 0 in case of a success, 0 in case of an error

Definition at line 26 of file Distance_HC_SR04.cpp.

Reset whole device and prepare for triggering of the next measurement in asynchronous non-blocking mode.

FSM set to IDLE state.

Definition at line 71 of file Distance_HC_SR04.cpp.

Set the actual value of coefficient used to calculate distance from "echo" pulse duration.

Parameters:

coeff

Coeficient for multiplication with pulse duration in microseconds

Returns:

void -

Definition at line 166 of file Distance_HC_SR04.cpp.

Start the measurement in asynchronous non-blocking mode.

Generates pulse on "trig" output and checks proper value of "echo" signal. Sets FSM STATE and exits.

If "echo" is low right after "trig" pulse is generated, sets FSM state to "STARTED". In other case FSM sate is set to "ERROR_SIG".

Definition at line 89 of file Distance_HC_SR04.cpp.