Philip Thompson / SRF02

Simple library for reading distance from SRF02 Ultrasonic Sensor in I2C mode. With the use of imperial readings too

Fork of SRF02 by Craig Evans

Files at this revision

API Documentation at this revision

Revision 3:78c8202f8929, committed 2016-04-15

Comitter:
el15pjt
Date:
Fri Apr 15 13:24:10 2016 +0000
Parent:
2:ad1613b4145c
Commit message:
Menus added. Bug in buzzer still!

Changed in this revision

SRF02.cpp Show annotated file Show diff for this revision Revisions of this file
SRF02.h Show annotated file Show diff for this revision Revisions of this file 
diff -r ad1613b4145c -r 78c8202f8929 SRF02.cpp
--- a/SRF02.cpp	Fri Mar 18 15:03:50 2016 +0000
+++ b/SRF02.cpp	Fri Apr 15 13:24:10 2016 +0000
@@ -15,6 +15,34 @@
 
 }
 
+int SRF02::getDistannceInch()
+{
+    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,&reg,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];
+}
 int SRF02::getDistanceCm()
 {
     char data[2];

diff -r ad1613b4145c -r 78c8202f8929 SRF02.h
--- a/SRF02.h	Fri Mar 18 15:03:50 2016 +0000
+++ b/SRF02.h	Fri Apr 15 13:24:10 2016 +0000
@@ -73,7 +73,7 @@
     * 
     */
     int getDistanceCm();
-
+int getDistannceInch();
 private:
     /** Hangs in infinite loop flashing 'blue lights of death'
     *