Dev Joshi
/
SRF02_libv2
Library for the SRF02 ultrasonic rangefinder
SRF02.cpp@0:862f11d627f9, 2011-07-10 (annotated)
- Committer:
- go2dev
- Date:
- Sun Jul 10 16:40:35 2011 +0000
- Revision:
- 0:862f11d627f9
v2 of this library, condenses the code base as discussed in this thread: http://mbed.org/forum/helloworld/topic/2234/
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
go2dev | 0:862f11d627f9 | 1 | |
go2dev | 0:862f11d627f9 | 2 | |
go2dev | 0:862f11d627f9 | 3 | /*Library for SRF02 ultrasonic range finder*/ |
go2dev | 0:862f11d627f9 | 4 | #include "SRF02.h" |
go2dev | 0:862f11d627f9 | 5 | |
go2dev | 0:862f11d627f9 | 6 | |
go2dev | 0:862f11d627f9 | 7 | |
go2dev | 0:862f11d627f9 | 8 | SRF02::SRF02(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr){ |
go2dev | 0:862f11d627f9 | 9 | //no initialisation code required here |
go2dev | 0:862f11d627f9 | 10 | } |
go2dev | 0:862f11d627f9 | 11 | |
go2dev | 0:862f11d627f9 | 12 | SRF02::~SRF02(){ |
go2dev | 0:862f11d627f9 | 13 | |
go2dev | 0:862f11d627f9 | 14 | } |
go2dev | 0:862f11d627f9 | 15 | |
go2dev | 0:862f11d627f9 | 16 | float SRF02::measurecm() { |
go2dev | 0:862f11d627f9 | 17 | float result = dosonar(0x51); |
go2dev | 0:862f11d627f9 | 18 | return result; |
go2dev | 0:862f11d627f9 | 19 | } |
go2dev | 0:862f11d627f9 | 20 | |
go2dev | 0:862f11d627f9 | 21 | float SRF02::measureus() { |
go2dev | 0:862f11d627f9 | 22 | float result = dosonar(0x52); |
go2dev | 0:862f11d627f9 | 23 | return result; |
go2dev | 0:862f11d627f9 | 24 | } |
go2dev | 0:862f11d627f9 | 25 | |
go2dev | 0:862f11d627f9 | 26 | float SRF02::measurein() { |
go2dev | 0:862f11d627f9 | 27 | float result = dosonar(0x50); |
go2dev | 0:862f11d627f9 | 28 | return result; |
go2dev | 0:862f11d627f9 | 29 | } |
go2dev | 0:862f11d627f9 | 30 | |
go2dev | 0:862f11d627f9 | 31 | |
go2dev | 0:862f11d627f9 | 32 | float SRF02::dosonar(char rangetype){ |
go2dev | 0:862f11d627f9 | 33 | //local variables |
go2dev | 0:862f11d627f9 | 34 | const char m_addr = 0xE0; //srf02 default slave address |
go2dev | 0:862f11d627f9 | 35 | char commandsequence[2]; |
go2dev | 0:862f11d627f9 | 36 | |
go2dev | 0:862f11d627f9 | 37 | // Get range data from SRF02 in cm |
go2dev | 0:862f11d627f9 | 38 | // Send Tx burst command over I2C bus |
go2dev | 0:862f11d627f9 | 39 | commandsequence[0] = 0x00; // Command register |
go2dev | 0:862f11d627f9 | 40 | commandsequence[1] = rangetype; // Ranging results type |
go2dev | 0:862f11d627f9 | 41 | m_i2c.write(m_addr, commandsequence, 2); // Request ranging from sensor |
go2dev | 0:862f11d627f9 | 42 | wait(0.07); // Average wait time for sonar pulse and processing |
go2dev | 0:862f11d627f9 | 43 | // Read back range over I2C bus |
go2dev | 0:862f11d627f9 | 44 | commandsequence[0] = 0x02; // |
go2dev | 0:862f11d627f9 | 45 | m_i2c.write(m_addr, commandsequence, 1, 1); // |
go2dev | 0:862f11d627f9 | 46 | m_i2c.read(m_addr, commandsequence, 2); // Read two-byte echo result |
go2dev | 0:862f11d627f9 | 47 | //combine upper and lower bytes in to a single value |
go2dev | 0:862f11d627f9 | 48 | float range = ((commandsequence[0] << 8) + commandsequence[1]); |
go2dev | 0:862f11d627f9 | 49 | return range; |
go2dev | 0:862f11d627f9 | 50 | |
go2dev | 0:862f11d627f9 | 51 | } |
go2dev | 0:862f11d627f9 | 52 |