PING.h

00001 #ifndef MBED_PING_H
00002 #define MBED_PING_H
00003 #include "mbed.h"
00004 
00005 /* Class: PING
00006  *  Abstraction for the PING Ultrasonic range finder
00007  *
00008  * Example:
00009  * > // Print measured distance
00010  * >
00011  * > #include "mbed.h"
00012  * > #include "PING.h"
00013  * >
00014  * > PING ping(p9);
00015  * >
00016  * > int main() {
00017  * >     while(1) {
00018  * >         printf("Measured : %.1f\n", ping.read());
00019  * >         wait(0.2);
00020  * >     }
00021  * > }
00022  */
00023 class PING
00024 {
00025 // Public functions
00026 public:
00027    /* Constructor: PING
00028     *  Create a PING object, connected to the specified pins
00029     *
00030     * Variables:
00031     *  trigger - Output to trigger the PING
00032     */
00033    PING(PinName trigger);
00034 
00035    /* Function: read
00036     *  A non-blocking function that will return the last measurement
00037     *
00038     * Variables:
00039     *  returns - floating point representation in cm.
00040     */
00041    float read(void);
00042 
00043    /* Function: read_in
00044     *  A non-blocking function that will return the last measurement
00045     *
00046     * Variables:
00047     *  returns - floating point representation in in.
00048     */
00049    float read_in(void);
00050 
00051    /* Function: operator float
00052     *  A short hand way of using the read function
00053     *
00054     * Example:
00055     * > float range = ping.read();
00056     * > float range = ping;
00057     * >
00058     * > if(ping.read() > 0.25) { ... }
00059     * > if(ping > 0.25) { ... }
00060     */
00061    operator float();
00062 
00063 private :
00064    DigitalInOut _trigger;
00065    Timer _timer;
00066    Ticker _ticker;
00067    void _startRange(void);
00068    float _dist;
00069 };
00070 
00071 #endif