Simple library for interfacing with SRF02 ultrasonic rage finder (written by C. Evans @eencae). Additions include a function for obtaining readings in inches
Fork of SRF02 by
Diff: SRF02.cpp
- Revision:
- 2:98253d9cbccd
- Parent:
- 0:b729d2ce03bd
diff -r 8e6587d88773 -r 98253d9cbccd SRF02.cpp --- a/SRF02.cpp Sun Mar 08 14:21:40 2015 +0000 +++ b/SRF02.cpp Mon May 11 16:35:20 2015 +0000 @@ -44,8 +44,37 @@ return (data[0] << 8) | data[1]; } -void SRF02::error() +int SRF02::getDistanceInch() { + char data[2]; + + // need to send CM command to command register + data[0] = CMD_REG; + data[1] = INCH_CMD; + int ack = i2c->write(SRF02_W_ADD,data,2); + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + // this will start the sensor ranging, the datasheet suggests a delay of at least 65 ms before reading the result + wait_ms(70); + + // we can now read the result - tell the sensor we want the high byte + char reg = RANGE_H_REG; + ack = i2c->write(SRF02_W_ADD,®,1); + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + // if we read two bytes, the register is automatically incremented (H and L) + ack = i2c->read(SRF02_R_ADD,data,2); + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + // high byte is first, then low byte, so combine into 16-bit value + return (data[0] << 8) | data[1]; +} + +void SRF02::error() { + while(1) { leds->write(15); wait(0.1);