Used command byte to return distance in inches.
Dependents: 2ndYearProject-DistanceSensor
Fork of SRF02 by
Diff: SRF02.cpp
- Revision:
- 2:45d62ec49ee9
- Parent:
- 0:b729d2ce03bd
--- a/SRF02.cpp Sun Mar 08 14:21:40 2015 +0000 +++ b/SRF02.cpp Sun Mar 27 22:48:51 2016 +0000 @@ -44,7 +44,36 @@ 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; // setting the new command byte to inches + 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() // error message ( flashing LED ) { while(1) { leds->write(15);