Diff: abstandsmesser.cpp

Revision:

0:0b5ee9c1af82

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/abstandsmesser.cpp	Mon Feb 07 15:47:47 2011 +0000
@@ -0,0 +1,121 @@
+/***************************************************************************************/
+/*****************        Facharbeit Jannick Pötzel 23.12.2011    **********************/
+/*****************         SRF08 Ultrasonic Range Finder          **********************/
+/***************************************************************************************/
+
+#include "mbed.h"
+#include "TextLCD.h"
+
+
+// allocation of variables
+TextLCD lcd(p24, p25, p26, p27, p28, p29, p30);
+
+DigitalOut mled0(LED1);
+DigitalOut mled1(LED2);
+DigitalOut mled2(LED3);
+DigitalOut mled3(LED4);
+
+I2C sonar(p9, p10);                         // Define SDA, SCL pins
+Serial pc(USBTX, USBRX);                    // Define Tx, Rx for PC
+const int addr = 0xE0;                      // I2C device address for SRF08
+char cmd[2];
+char echo[2];
+
+// start amin programm
+int main() {
+
+// Set up SRF08 max range and receiver sensitivity over I2C bus
+    cmd[0] = 0x02;                          // Range register
+    cmd[1] = 0x1C;                          // Set max range about 100cm
+    sonar.write(addr, cmd, 2);
+    cmd[0] = 0x01;                          // Receiver gain register
+    cmd[1] = 0x1B;                          // Set receiver gain
+    sonar.write(addr, cmd, 2);
+
+while(1)
+{
+
+// Get range data from SRF08
+// Send Tx burst command over I2C bus
+        cmd[0] = 0x00;                      // Command register
+        cmd[1] = 0x51;                      // Ranging results in cm
+        sonar.write(addr, cmd, 2);          // Send ranging burst
+
+        wait(0.07);                         // Wait for return echo
+
+// Read back range over I2C bus
+        cmd[0] = 0x02;                      // Address of first echo
+        sonar.write(addr, cmd, 1, 1);       // Send address of first echo       
+        sonar.read(addr, echo, 2);          // read two-byte echo result
+       
+// calculate distance            
+      int x = (echo[0]<<8)+echo[1];
+
+// clear LCD       
+      lcd.cls();
+// if distance bigger than 99 cm write out of R to LCD
+      if (x > 99)
+      {
+      lcd.writeData(' ');
+      lcd.writeData('o');
+      lcd.writeData('u');
+      lcd.writeData('t');
+      lcd.writeData(' ');
+      lcd.writeData('o');
+      lcd.writeData('f');
+      lcd.writeData(' ');
+      lcd.writeData('R');
+      }
+// write distance to LCD
+      else
+      {
+      int x1=0x30+x%10;
+      int x2=x/10;
+      x2=0x30+x2%10;
+      lcd.writeData(' ');
+      lcd.writeData(x2);
+      lcd.writeData(x1);
+      lcd.writeData(' ');
+      lcd.writeData('c');
+      lcd.writeData('m');
+      }
+
+// Power in LEDs in dependence of measured distance
+      
+        if (x <= 40)
+        {
+            mled0 = 1;
+            mled1 = 0;
+            mled2 = 0;
+            mled3 = 0; 
+        }
+       if (x <= 30)
+        {
+           mled0 = 1;
+           mled1 = 1;
+           mled2 = 0;
+           mled3 = 0;
+        }
+       if (x <= 20)
+        {
+          mled0 = 1;
+          mled1 = 1;
+          mled2 = 1;
+          mled3 = 0;
+        }
+       if (x <= 10)
+        {
+          mled0 = 1;
+          mled1 = 1;
+          mled2 = 1;
+          mled3 = 1;
+        }
+       else if (x > 40)
+        {
+          mled0 = 0;
+          mled1 = 0;
+          mled2 = 0;
+          mled3 = 0;
+        }
+  }       
+}