Works with the parallax ping sensor. Uses a timer and interrupts to get the time and calculate the distance
Dependents: Wifly_TCPEchoServer_Sensors ROBOT_v01 ROBOT_v02 mbed_blinky ... more
Revision 0:1e4b66122368, committed 2011-03-12
- Comitter:
- rosienej
- Date:
- Sat Mar 12 22:26:10 2011 +0000
- Child:
- 1:6996f66161d7
- Commit message:
- beta
Changed in this revision
Ping.cpp | Show annotated file Show diff for this revision Revisions of this file |
Ping.h | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Ping.cpp Sat Mar 12 22:26:10 2011 +0000 @@ -0,0 +1,54 @@ +#include "Ping.h" + +#include "mbed.h" + +Ping::Ping(PinName PING_PIN) + : _event(PING_PIN) + , _cmd(PING_PIN) + , _timer() + { + _event.rise(this,&Ping::_Starts); + _event.fall(this,&Ping::_Stops); + _SPEED_OF_SOUND_CM = 33; + } + +void Ping::_Starts(void) +{ + _Valid = false; // start the timere, and invalidate the current time. + _Busy = true; + _timer.start(); + _Time = _timer.read_us(); +} + +void Ping::_Stops(void) +{ + _Valid = true; // When it stops, update the time + _Busy = false; + _Time = _timer.read_us()-_Time; +} + +void Ping::Send() +{ + + _cmd.output(); + _cmd.write(0); // see the ping documentation http://www.parallax.com/Portals/0/Downloads/docs/prod/acc/28015-PING-v1.6.pdf + wait_us(3); + _cmd.write(1); + wait_us(3); + _cmd.write(0); + _cmd.input(); + +} +void Ping::Set_Speed_of_Sound(int SoS_ms ) +{ + _SPEED_OF_SOUND_CM = SoS_ms; +} + +int Ping::Read_cm() +// -1 means not valid. +{ + if(_Valid && ~_Busy) + return ((_Time*_SPEED_OF_SOUND_CM)/1000); + else + return -1; +} \ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Ping.h Sat Mar 12 22:26:10 2011 +0000 @@ -0,0 +1,93 @@ +/* mbed Ping Library + * Copyright (c) 2007-2010 rosienej + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + + #ifndef MBED_PING_H + #define MBED_PING_H + +#include "mbed.h" +/** Ping class, based on an InterruptIn pin, and a timer + * works with the parallax Ping))) sensor (www.parallax.com) + * + * Example: + * @code + * // Continuously send pings and read the sensor + * #include "mbed.h" + * #include "Ping.h" + * + * Ping Pinger(p21); + * + * int main() { + * int range; + + * while(1) { + * + * Pinger.Send(); + * wait_ms(30); + * range = Pinger.Read_cm(); + * } + * } + * @endcode + */ + class Ping { + public: + /** Create a Ping object connected to the specified InterruptIn pin + * + * @param PING_PIN InterruptIn pin to connect to + */ + Ping(PinName PING_PIN); + + /** Sends a Ping + * + * @param none + */ + void Send(void); + + /** Set the speed of sound, default 33 cm/ms + * + * @param Speed of sound in centimeters per milliseconds + */ + void Set_Speed_of_Sound(int SoS_ms); + + /** Read the result in centimeters + * + * @param none + */ + int Read_cm(void); + + protected: + + InterruptIn _event; + DigitalInOut _cmd; + Timer _timer; + + bool _Valid; + bool _Busy; + int _Time; + int _SPEED_OF_SOUND_CM; /* in milliseconds */ + + void _Starts(void); + void _Stops(void); + + }; + + #endif + \ No newline at end of file