Dev Joshi
Library for the SRF02 ultrasonic rangefinder
Revision 0:862f11d627f9, committed 2011-07-10
- Comitter:
- go2dev
- Date:
- Sun Jul 10 16:40:35 2011 +0000
- Commit message:
- v2 of this library, condenses the code base as discussed in this thread: http://mbed.org/forum/helloworld/topic/2234/
Changed in this revision
diff -r 000000000000 -r 862f11d627f9 SRF02.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SRF02.cpp Sun Jul 10 16:40:35 2011 +0000
@@ -0,0 +1,52 @@
+
+
+/*Library for SRF02 ultrasonic range finder*/
+#include "SRF02.h"
+
+
+
+SRF02::SRF02(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr){
+ //no initialisation code required here
+ }
+
+SRF02::~SRF02(){
+
+}
+
+float SRF02::measurecm() {
+ float result = dosonar(0x51);
+ return result;
+}
+
+float SRF02::measureus() {
+ float result = dosonar(0x52);
+ return result;
+}
+
+float SRF02::measurein() {
+ float result = dosonar(0x50);
+ return result;
+}
+
+
+float SRF02::dosonar(char rangetype){
+ //local variables
+ const char m_addr = 0xE0; //srf02 default slave address
+ char commandsequence[2];
+
+ // Get range data from SRF02 in cm
+ // Send Tx burst command over I2C bus
+ commandsequence[0] = 0x00; // Command register
+ commandsequence[1] = rangetype; // Ranging results type
+ m_i2c.write(m_addr, commandsequence, 2); // Request ranging from sensor
+ wait(0.07); // Average wait time for sonar pulse and processing
+ // Read back range over I2C bus
+ commandsequence[0] = 0x02; //
+ m_i2c.write(m_addr, commandsequence, 1, 1); //
+ m_i2c.read(m_addr, commandsequence, 2); // Read two-byte echo result
+ //combine upper and lower bytes in to a single value
+ float range = ((commandsequence[0] << 8) + commandsequence[1]);
+ return range;
+
+}
+
diff -r 000000000000 -r 862f11d627f9 SRF02.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SRF02.h Sun Jul 10 16:40:35 2011 +0000
@@ -0,0 +1,95 @@
+/* mbed SRF02 Ultra Sonic Range Finder Library
+ * Copyright (c) 2011 by djoshi [go2dev]
+ * 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.
+ */
+
+
+/*Header file for the SRF02 sonar range finder class*/
+#ifndef SRF02_H
+#define SRF02_H
+
+#include "mbed.h"
+
+//!Library for the SRF02 Ultrasonic Ranger
+/*
+ * The SRF02 is an I2C Ultrasonic rangefinder which can return values for measured
+ * distance as either time of flight (uS) or directly in cm or in.
+
+ * Example Usage:
+ * @code
+ * //Take a measurement of the current distance (in cm), print the result to the terminal via the debug port
+ * #include "mbed.h"
+ * #include "SRF02.h"
+ *
+ * Serial debugport(USBTX,USBRX);
+ * SRF02 mySensor(p9,p10,0xE0);
+ * main() {
+ * while (1) {
+ * debugport.printf("current distance: %.2f cm. \r\n", mySensor.measurecm());
+ * }
+ * }
+ * @endcode
+*/
+
+*/
+
+class SRF02 {
+public:
+ /** Create a SRF02 object connected to the specified I2C pins
+ *
+ * @param sda I2C Data pin to connect to
+ * @param scl I2C Clock pin to connect to
+ */
+ SRF02(PinName sda, PinName scl, int addr);
+
+ /** Destroys an instance of SRD02
+ */
+ ~SRF02();
+
+ /** Get the current distance in centimetres
+ *
+ * @param returns the measured distance in centimetres as a float
+ */
+ float measurecm();
+
+ /** Get the current distance in centimetres
+ *
+ * @param returns the measured distance in inches as a float
+ */
+ float measurein();
+
+ /** Get the current distance in centimetres
+ *
+ * @param returns the time of flight from the pulse sent from the sensor in microseconds (uS) as a float
+ */
+ float measureus();
+
+
+private:
+ I2C m_i2c;
+ int m_addr;
+
+ /** dosonar is an internal function for this library which actually manages the I2C transaction with the sensor to get a reading.
+ * It is not directly accessible by the user via the libaray
+ */
+ float dosonar(char rangetype);
+
+
+};
+#endif
\ No newline at end of file
diff -r 000000000000 -r 862f11d627f9 main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sun Jul 10 16:40:35 2011 +0000
@@ -0,0 +1,30 @@
+//Useage example for the SRF02 Library
+
+#include "mbed.h"
+#include "SRF02.h"
+
+
+Serial debugport(USBTX,USBRX);
+SRF02 mySensor(p9,p10,0xE0);
+
+
+
+
+main() {
+
+ time_t seconds = time(NULL); //Internal RTC
+ debugport.baud(115200); //set the buadrate (default is 9600 if this command is not used)
+ debugport.format(8,Serial::None,1); //config the serial port (default is 8N1)
+ debugport.printf("Hello World! %d \r\n", seconds); //send a message out of the serial port to check all is well
+ //include a time stamp for reference (seconds since power up)
+
+
+ while (1) {
+
+
+ debugport.printf("current distance: %.2f cm. (v2) \r\n", mySensor.measurecm());
+ debugport.printf("current distance: %.2f inches.\r\n", mySensor.measurein());
+ debugport.printf("current flightime: %.2f microseconds.\r\n", mySensor.measureus());
+
+ }
+}
diff -r 000000000000 -r 862f11d627f9 mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Sun Jul 10 16:40:35 2011 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/63bcd7ba4912