added lab 3

S3/sensor.c

@@ -3,23 +3,61 @@
 #include "dev/sht11-sensor.h"
 #include <stdio.h> /* For printf() */
 
+typedef unsigned short USHORT;
+
+//print a unsigned short (as returned from rand) picewise char by char
+void
+putShort(USHORT in) 
+{
+	// recursively shift each digit of the int to units from most to least significant
+	if (in >= 10)
+	{
+		putShort(in / 10);
+	}
+	// isolate unit digit from each number by modulo and add '0' char to turn integer into corresponding ascii char
+	putchar((in % 10) + '0');
+}
+
+void
+putFloat(float in) 
+{
+	if(in < 0) 
+	{
+		putchar('-'); // print negative sign if required
+		in = -in;
+	}	
+	
+	USHORT integerComponent = (USHORT) in; // truncate float to integer
+	float fractionComponent =  (in - integerComponent) * 1000; // take fraction only and promote to integer
+	if (fractionComponent - (USHORT)fractionComponent >= 0.5) fractionComponent++; // round
+
+	putShort(integerComponent);
+	putchar('.');
+	putShort((USHORT) fractionComponent);
+}
+
 float getTemperature(void)
 {
   	int tempData;
 
   	// NOTE: You only need to use one of the following
   	// If you run the code in Cooja Simulator, please remove the second one
-  //tempData = sht11_sensor.value(SHT11_SENSOR_TEMP_SKYSIM); // For Cooja Sim
+  	tempData = sht11_sensor.value(SHT11_SENSOR_TEMP_SKYSIM); // For Cooja Sim
-  tempData = sht11_sensor.value(SHT11_SENSOR_TEMP); // For XM1000 mote
+  	//tempData = sht11_sensor.value(SHT11_SENSOR_TEMP); // For XM1000 mote
 
-  float temp = tempData; // you need to implement the transfer function here
+	float d1 = -39.6f;
+	float d2 = 0.01f;
+  	float temp = d1 + (d2 * tempData); // you need to implement the transfer function here
   	return temp;
 }
 
 float getLight(void)
 {
   	int lightData = light_sensor.value(LIGHT_SENSOR_PHOTOSYNTHETIC);
-  float light = lightData; // you need to implement the transfer function here
+
+	float V_sensor = 1.5 * lightData / 4096;
+	float I = V_sensor/1e5;
+  	float light = 0.625 * 1e6 * I * 1000; // you need to implement the transfer function here
   	return light;
 }
 
@@ -32,8 +70,7 @@ PROCESS_THREAD(sensor_reading_process, ev, data)
 {
   static struct etimer timer;
   PROCESS_BEGIN();
-  etimer_set(&timer, CLOCK_CONF_SECOND/4); // you need to put the correct 
+  etimer_set(&timer, CLOCK_SECOND); // you need to put the correct timer setting here
-                                           // timer setting here
   SENSORS_ACTIVATE(light_sensor);
   SENSORS_ACTIVATE(sht11_sensor);
 
@@ -45,8 +82,17 @@ PROCESS_THREAD(sensor_reading_process, ev, data)
     float temp = getTemperature();
     float light_lx = getLight();
 
-    printf("%d\n", ++counter); // you should also print the temperature
+    printf("%d\n", ++counter); // you should also print the temperature and light intensity here
-                               // and light intensity here
+	printf("Temperature: ");
+	putFloat(temp);
+	printf(" C");
+	putchar('\n');
+
+	printf("Light: ");
+	putFloat(light_lx);
+	putchar('\n');
+
+	putchar('\n');
 
     etimer_reset(&timer);
   }

S3/symbols.c

@@ -0,0 +1,4 @@
+#include "symbols.h"
+
+const int symbols_nelts = 0;
+const struct symbols symbols[] = {{0,0}};

S3/symbols.h

@@ -0,0 +1,3 @@
+#include "loader/symbols.h"
+
+extern const struct symbols symbols[1];