diff --git a/os/various/devices_lib/sensors/tsl2561.c b/os/various/devices_lib/sensors/tsl2561.c
index 3d7b9107..a4ac8ec5 100644
--- a/os/various/devices_lib/sensors/tsl2561.c
+++ b/os/various/devices_lib/sensors/tsl2561.c
@@ -15,7 +15,7 @@
 */
 
 /**
- *
+ * Illuminance calculation code provided by www.taosinc.com
  * DOC: http://ams.com/eng/content/download/250096/975518/143687
  */
 #define I2C_HELPERS_AUTOMATIC_DRV TRUE
@@ -131,10 +131,6 @@
 #define TSL2561_LUX_M8C           (0x0000)  // 0.000   * 2^LUX_SCALE
 
 
-
-
-#define CEILING(x,y) (((x) + (y) - 1) / (y))
-
 /*===========================================================================*/
 /* Driver exported variables.                                                */
 /*===========================================================================*/
@@ -147,6 +143,8 @@
 /* Driver local functions.                                                   */
 /*===========================================================================*/
 
+#define CEILING(x,y) (((x) + (y) - 1) / (y))
+
 static inline unsigned int
 calculateIlluminance(TSL2561_integration_time_t integration_time,
 		     TSL2561_gain_t gain,
@@ -276,7 +274,7 @@ void
 TSL2561_init(TSL2561_drv *drv, TSL2561_config *config) {
     drv->config           = config;
     drv->gain             = TSL2561_GAIN_1X;
-    drv->integration_time = TSL2561_INTEGRATIONTIME_SHORT;
+    drv->integration_time = TSL2561_INTEGRATIONTIME_LONG;
     drv->state            = SENSOR_INIT;
 
     i2c_reg_recv8(TSL2561_COMMAND_BIT | TSL2561_REG_ID,
@@ -297,7 +295,7 @@ TSL2561_check(TSL2561_drv *drv) {
   
 msg_t
 TSL2561_stop(TSL2561_drv *drv) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2561_COMMAND_BIT | TSL2561_REG_CONTROL,
@@ -308,7 +306,7 @@ TSL2561_stop(TSL2561_drv *drv) {
 
 msg_t
 TSL2561_start(TSL2561_drv *drv) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2561_COMMAND_BIT | TSL2561_REG_CONTROL,
@@ -320,7 +318,7 @@ TSL2561_start(TSL2561_drv *drv) {
 msg_t
 TSL2561_setIntegrationTime(TSL2561_drv *drv,
 	TSL2561_integration_time_t time) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2561_COMMAND_BIT | TSL2561_REG_TIMING,
@@ -338,7 +336,7 @@ TSL2561_setIntegrationTime(TSL2561_drv *drv,
 msg_t
 TSL2561_setGain(TSL2561_drv *drv,
 	TSL2561_gain_t gain) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2561_COMMAND_BIT | TSL2561_REG_TIMING,
diff --git a/os/various/devices_lib/sensors/tsl2561.h b/os/various/devices_lib/sensors/tsl2561.h
index 94e1ede9..75e7c78e 100644
--- a/os/various/devices_lib/sensors/tsl2561.h
+++ b/os/various/devices_lib/sensors/tsl2561.h
@@ -87,16 +87,26 @@ typedef struct {
     I2CHelper i2c; /* keep it first */
 } TSL2561_config;
 
-
+/**
+ * @brief   Available integration time
+ *
+ * @details Available integration time are:
+ *          13.7ms, 101ms, 402ms
+ */
 typedef enum {
-    TSL2561_INTEGRATIONTIME_SHORT      = 0x00,    // 13.7ms
-    TSL2561_INTEGRATIONTIME_MEDIUM     = 0x01,    // 101ms
-    TSL2561_INTEGRATIONTIME_LONG       = 0x02,    // 402ms
+    TSL2561_INTEGRATIONTIME_SHORT      = 0x00,    /**< @brief  13.7ms */
+    TSL2561_INTEGRATIONTIME_MEDIUM     = 0x01,    /**< @brief 101.0ms */
+    TSL2561_INTEGRATIONTIME_LONG       = 0x02,    /**< @brief 402.0ms */
 } TSL2561_integration_time_t;
 
+/**
+ * @brief   Available gain
+ *
+ * @details Available gain are 1x, 16x
+ */
 typedef enum {
-    TSL2561_GAIN_1X                    = 0x00,    // No gain
-    TSL2561_GAIN_16X                   = 0x10,    // 16x gain
+    TSL2561_GAIN_1X                    = 0x00,    /**< @brief  1x gain */
+    TSL2561_GAIN_16X                   = 0x10,    /**< @brief 16x gain */
 } TSL2561_gain_t;
 
 /**
@@ -105,8 +115,6 @@ typedef enum {
 typedef struct {
     TSL2561_config  *config;
     sensor_state_t   state;
-    unsigned int     delay;    
-    uint16_t         cfg;
     TSL2561_gain_t   gain;
     TSL2561_integration_time_t integration_time;
     struct PACKED {
diff --git a/os/various/devices_lib/sensors/tsl2591.c b/os/various/devices_lib/sensors/tsl2591.c
index 214b1ce6..c0bbee0c 100644
--- a/os/various/devices_lib/sensors/tsl2591.c
+++ b/os/various/devices_lib/sensors/tsl2591.c
@@ -163,29 +163,48 @@ TSL2591_check(TSL2591_drv *drv) {
 
 msg_t
 TSL2591_start(TSL2591_drv *drv) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
-    } tx = { TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_ENABLE,
-	     TSL2591_ENABLE_POWERON | TSL2591_ENABLE_AEN | TSL2591_ENABLE_AIEN };
-    return i2c_send((uint8_t*)&tx, sizeof(tx));
+    } tx_config = {
+	TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_CONFIG,
+	(uint8_t)(drv->integration_time | drv->gain) };
+
+    struct __attribute__((packed)) {
+	uint8_t reg;
+	uint8_t conf;
+    } tx_start = {
+	TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_ENABLE,
+	TSL2591_ENABLE_POWERON };
+
+    msg_t msg;
+
+    if (((msg = i2c_send((uint8_t*)&tx_config, sizeof(tx_config))) < MSG_OK) ||
+	((msg = i2c_send((uint8_t*)&tx_start,  sizeof(tx_start ))) < MSG_OK)) {
+	drv->state = SENSOR_ERROR;
+	return msg;
+    }
+    
+    drv->state = SENSOR_STARTED;
+    return MSG_OK;
 }
 
 msg_t
 TSL2591_stop(TSL2591_drv *drv) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
-    } tx = { TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_ENABLE,
-	     TSL2591_ENABLE_POWEROFF };
+    } tx_stop = {
+	TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_ENABLE,
+	TSL2591_ENABLE_POWEROFF };
     
-    return i2c_send((uint8_t*)&tx, sizeof(tx));
+    return i2c_send((uint8_t*)&tx_stop, sizeof(tx_stop));
 }
 
 msg_t
 TSL2591_setIntegrationTime(TSL2591_drv *drv,
 	TSL2591_integration_time_t time) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_CONFIG,
@@ -203,7 +222,7 @@ TSL2591_setIntegrationTime(TSL2591_drv *drv,
 msg_t
 TSL2591_setGain(TSL2591_drv *drv,
 	TSL2591_gain_t gain) {
-    struct PACKED {
+    struct __attribute__((packed)) {
 	uint8_t reg;
 	uint8_t conf;
     } tx = { TSL2591_REG_COMMAND | TSL2591_REG_NORMAL | TSL2591_REG_CONFIG,
diff --git a/os/various/devices_lib/sensors/tsl2591.h b/os/various/devices_lib/sensors/tsl2591.h
index e6597bf4..8320eb8a 100644
--- a/os/various/devices_lib/sensors/tsl2591.h
+++ b/os/various/devices_lib/sensors/tsl2591.h
@@ -113,9 +113,7 @@ typedef enum {
 typedef struct {
     TSL2591_config  *config;
     sensor_state_t   state;
-    unsigned int     delay;    
-    uint16_t         cfg;
-    TSL2591_gain_t   gain;
+    TSL2591_gain_t gain;
     TSL2591_integration_time_t integration_time;
 } TSL2591_drv;