diff --git a/am2302.c b/am2302.c
index 57b248d..d1b4d6c 100644
--- a/am2302.c
+++ b/am2302.c
@@ -58,6 +58,15 @@
 #define SENSOR_is_low		!(PIN_SENSOR & (1 << SENSOR))
 
 
+/**
+ * @brief init avr for am2302 sda
+ */
+inline void am2302_init(void);
+{
+	DDR_SENSOR &= ~(1 << SENSOR); // define as input
+	PORT_SENSOR &= ~(1 << SENSOR);  // disable pullup
+}
+
 uint8_t am2302(uint16_t *humidity, uint16_t *temp)
 {
 	if (SENSOR_is_low)
@@ -73,13 +82,35 @@
 
 	// Bus master has released time min: 20us, typ: 30us, max: 200us
 	uint8_t timeout = 200;
-	while(SENSOR_is_hi) {_delay_us(1); if (!timeout--) {return 2;}}
+	while(SENSOR_is_hi)
+	{
+		_delay_us(1);
+		if (!timeout--)
+		{
+			return 2;
+		}
+	}
 
 	// AM2302 response signal min: 75us typ:80us max:85us
 	timeout = 85;
-	while(SENSOR_is_low) {_delay_us(1); if (!timeout--) {return 3;}}  // response to low time
+	while(SENSOR_is_low)
+	{
+		_delay_us(1);
+		if (!timeout--)
+		{
+			return 3;
+		}
+	}  // response to low time
+
 	timeout = 85;
-	while(SENSOR_is_hi) {_delay_us(1); if (!timeout--) {return 4;}}  // response to high time
+	while(SENSOR_is_hi)
+	{
+		_delay_us(1);
+		if (!timeout--)
+		{
+			return 4;
+		}
+	}  // response to high time
 
 
 	/*
@@ -90,35 +121,63 @@
 	 */
 
 	uint8_t sensor_data[5]={0};
+
 	for(uint8_t i = 0; i < 5; i++)
 	{
 		uint8_t sensor_byte = 0;
-		for(uint8_t j = 1; j <= 8; j++) // get 8 bits from sensor
+	
+		// get 8 bits from sensor
+		for(uint8_t j = 1; j <= 8; j++)
 		{
+			// wait for sensor response
 			timeout = 55;
-			while(SENSOR_is_low) {_delay_us(1); if (!timeout--) {return 5;}} // signal "0", "1" low time
-			_delay_us(30);
-			sensor_byte <<= 1; // add new lower byte
-			if (SENSOR_is_hi) // if sda high after 30us => bit=1 else bit=0
+			while(SENSOR_is_low)
 			{
-				sensor_byte |= 1;
+				_delay_us(1);
+
+				// if timeout == 0 => sensor do not response
+				if (!timeout--)
+				{
+					return 5;
+				}
+			}
+
+			// wait 30 us to check if bit is logical "1" or "0"
+			_delay_us(30);
+			sensor_byte <<= 1; // add new lower bit
+
+			// If sda ist high after 30 us then bit is logical "1" else it was a logical "0"
+			// For a logical "1" sda have to be low after 75 us.
+			if (SENSOR_is_hi)
+			{
+				sensor_byte |= 1; // add logical "1"
 				timeout = 45;  // 30us - 75us = 45us
-				while(SENSOR_is_hi) {_delay_us(1); if (!timeout--) {return 6;}}
+
+				while(SENSOR_is_hi)
+				{
+					_delay_us(1);
+				
+					if (!timeout--)
+					{
+						return 6;
+					}
+				}
 			}
 		}
+
 		sensor_data[i] = sensor_byte;
 	}
 
 	// checksum
-	if ( ((sensor_data[0]+sensor_data[1]+sensor_data[2]+sensor_data[3]) & 0xff ) != sensor_data[4])
+	if ( ((sensor_data[0] + sensor_data[1] + sensor_data[2] + sensor_data[3]) & 0xff ) != sensor_data[4])
 	{
 		// debug output
 		//printf("%b %b %b %b %b %b" CR, sensor_data[0], sensor_data[1], sensor_data[2], sensor_data[3], sensor_data[4], ((sensor_data[0]+sensor_data[1]+sensor_data[2]+sensor_data[3]) & 0xff ));
 		return 7;
 	}
 
-	*humidity = (sensor_data[0]<<8) + sensor_data[1];
-	*temp = (sensor_data[2]<<8) + sensor_data[3];
+	*humidity = (sensor_data[0] << 8) + sensor_data[1];
+	*temp = (sensor_data[2] << 8) + sensor_data[3];
 
 	return 0;
 }
diff --git a/am2302.h b/am2302.h
index 59c731b..03c1b18 100644
--- a/am2302.h
+++ b/am2302.h
@@ -26,7 +26,7 @@
 
 
 uint8_t am2302(uint16_t *humidity, uint16_t *temp);
-
+inline void am2302_init(void);
 
 
 #endif /* AM2302_H_ */
diff --git a/main.c b/main.c
index 84ead68..a018805 100644
--- a/main.c
+++ b/main.c
@@ -34,11 +34,9 @@
 
 int main(void)
 {
-	DDR_SENSOR &= ~(1 << SENSOR); // define as input
+	am2302_init();
 	DDR_LED |= (1 << LED); // define as output
 
-	PORT_SENSOR &= ~(1 << SENSOR);  // disable pullup
-
 	led_off;
 
 	uart_init(BAUDRATE);
@@ -51,9 +49,10 @@
 		uint16_t humidity = 0;
 		uint16_t temp = 0;
 
+		// turn led on at measurement
 		led_on;
 
-		uint8_t error = am2302(&humidity, &temp);
+		uint8_t error = am2302(&humidity, &temp); // get data from am2302
 		if (!error)
 		{
 			printf("%i,%i%% %i,%iC" CR, humidity/10, humidity%10, temp/10, temp%10);
@@ -63,8 +62,10 @@
 			printf("Error %i" CR, error);
 		}
 
+		// turn led off;
 		led_off;
 		
+		// wait one second
 		_delay_ms(1000);
 	}