diff --git a/conf/modules/airspeed_ets.xml b/conf/modules/airspeed_ets.xml
index 5e35f2c7cb..9bde519b64 100644
--- a/conf/modules/airspeed_ets.xml
+++ b/conf/modules/airspeed_ets.xml
@@ -5,6 +5,8 @@
      @param AIRSPEED_ETS_SCALE scale factor (default 1.8)
      @param AIRSPEED_ETS_OFFSET offset (default 0)
      @param AIRSPEED_ETS_I2C_DEV i2c device (default i2c0)
+     @flag USE_AIRSPEED to use the data for airspeed control loop
+     @flag SENSOR_SYNC_SEND to transmit the data as it is acquired
      -->
 
 <module name="airspeed_ets" dir="sensors">
@@ -18,7 +20,6 @@
 
   <makefile>
     <file name="airspeed_ets.c"/>
-    <flag name="USE_AIRSPEED"/>
   </makefile>
 
 </module>
diff --git a/conf/modules/baro_bmp.xml b/conf/modules/baro_bmp.xml
index 1e01d1c1cc..288036c05c 100644
--- a/conf/modules/baro_bmp.xml
+++ b/conf/modules/baro_bmp.xml
@@ -1,5 +1,11 @@
 <!DOCTYPE module SYSTEM "module.dtd">
 
+<!--
+     Bosch BMP085 pressure sensor
+     @param BMP_I2C_DEV i2c device (default i2c0)
+     @flag SENSOR_SYNC_SEND to transmit the data as it is acquired
+     -->
+
 <module name="baro_bmp" dir="sensors">
   <header>
     <file name="baro_bmp.h"/>
diff --git a/conf/modules/baro_scp.xml b/conf/modules/baro_scp.xml
index 31337accfa..f76579e90f 100644
--- a/conf/modules/baro_scp.xml
+++ b/conf/modules/baro_scp.xml
@@ -1,5 +1,10 @@
 <!DOCTYPE module SYSTEM "module.dtd">
 
+<!--
+     VTI SCP1000 pressure sensor (SPI)
+     @flag SENSOR_SYNC_SEND to transmit the data as it is acquired
+     -->
+
 <module name="baro_scp" dir="sensors">
   <header>
     <file name="baro_scp.h"/>
diff --git a/conf/modules/baro_scp_i2c.xml b/conf/modules/baro_scp_i2c.xml
index c6e7006882..972be683b7 100644
--- a/conf/modules/baro_scp_i2c.xml
+++ b/conf/modules/baro_scp_i2c.xml
@@ -1,8 +1,9 @@
 <!DOCTYPE module SYSTEM "module.dtd">
 
 <!--
-     Baro SCP module (I2C)
+     VTI SCP1000 pressure sensor (I2C)
      @param SCP_I2C_DEV i2c device (default i2c0)
+     @flag SENSOR_SYNC_SEND to transmit the data as it is acquired
      -->
 
 <module name="baro_scp_i2c" dir="sensors">
diff --git a/sw/airborne/modules/sensors/airspeed_ets.c b/sw/airborne/modules/sensors/airspeed_ets.c
index 59d957de35..7b8ae76096 100644
--- a/sw/airborne/modules/sensors/airspeed_ets.c
+++ b/sw/airborne/modules/sensors/airspeed_ets.c
@@ -36,8 +36,18 @@
  */
 #include "sensors/airspeed_ets.h"
 #include "estimator.h"
+#include "i2c.h"
+#include "uart.h"
+#include "messages.h"
+#include "downlink.h"
 #include <math.h>
 
+#ifndef USE_AIRSPEED
+#ifndef SENSOR_SYNC_SEND
+#warning either set USE_AIRSPEED or SENSOR_SYNC_SEND to use ets_airspeed
+#endif
+#endif
+
 #define AIRSPEED_ETS_ADDR 0xEA
 #ifndef AIRSPEED_ETS_SCALE
 #define AIRSPEED_ETS_SCALE 1.8
@@ -149,7 +159,12 @@ void airspeed_ets_event( void ) {
       for (n = 0; n < AIRSPEED_ETS_NBSAMPLES_AVRG; ++n)
         airspeed_ets += airspeed_ets_buffer[n];
       airspeed_ets = airspeed_ets / (float)AIRSPEED_ETS_NBSAMPLES_AVRG;
+#ifdef USE_AIRSPEED
       EstimatorSetAirspeed(airspeed_ets);
+#endif
+#ifdef SENSOR_SYNC_SEND
+      DOWNLINK_SEND_AIRSPEED_ETS(DefaultChannel, &airspeed_ets_raw, &airspeed_ets_offset, &airspeed_ets);
+#endif
     } else {
       airspeed_ets = 0.0;
     }
diff --git a/sw/airborne/modules/sensors/baro_bmp.c b/sw/airborne/modules/sensors/baro_bmp.c
index 9d12b1e49b..34860b1ca0 100644
--- a/sw/airborne/modules/sensors/baro_bmp.c
+++ b/sw/airborne/modules/sensors/baro_bmp.c
@@ -38,6 +38,10 @@
 #include "messages.h"
 #include "downlink.h"
 
+#ifndef SENSOR_SYNC_SEND
+#warning set SENSOR_SYNC_SEND to use baro_bmp
+#endif
+
 #ifndef BMP_I2C_DEV
 #define BMP_I2C_DEV i2c0
 #endif
@@ -157,7 +161,9 @@ void baro_bmp_event( void ) {
 
       baro_bmp_temperature = bmp_t;
       baro_bmp_pressure = bmp_p;
+#ifdef SENSOR_SYNC_SEND
       DOWNLINK_SEND_BMP_STATUS(DefaultChannel, &bmp_p, &bmp_t);
+#endif
     }
   }
 }
diff --git a/sw/airborne/modules/sensors/baro_scp.c b/sw/airborne/modules/sensors/baro_scp.c
index b24f6aa7ec..45608092e7 100644
--- a/sw/airborne/modules/sensors/baro_scp.c
+++ b/sw/airborne/modules/sensors/baro_scp.c
@@ -12,6 +12,10 @@
 
 #include "baro_scp.h"
 
+#ifndef SENSOR_SYNC_SEND
+#warning set SENSOR_SYNC_SEND to use baro_scp
+#endif
+
 #define STA_UNINIT       0
 #define STA_INITIALISING 1
 #define STA_IDLE         2
@@ -171,7 +175,9 @@ static void baro_scp_read(void) {
 
 void baro_scp_event( void ) {
   if (baro_scp_available == TRUE) {
+#ifdef SENSOR_SYNC_SEND
     DOWNLINK_SEND_SCP_STATUS(DefaultChannel, &baro_scp_pressure, &baro_scp_temperature);
+#endif
     baro_scp_available = FALSE;
   }
 }
diff --git a/sw/airborne/modules/sensors/baro_scp_i2c.c b/sw/airborne/modules/sensors/baro_scp_i2c.c
index aef0cc365e..f45f89abd0 100644
--- a/sw/airborne/modules/sensors/baro_scp_i2c.c
+++ b/sw/airborne/modules/sensors/baro_scp_i2c.c
@@ -14,6 +14,10 @@
 #include "messages.h"
 #include "downlink.h"
 
+#ifndef SENSOR_SYNC_SEND
+#warning set SENSOR_SYNC_SEND to use baro_scp_i2c
+#endif
+
 uint8_t  baro_scp_status;
 uint32_t baro_scp_pressure;
 uint16_t baro_scp_temperature;
@@ -90,7 +94,9 @@ void baro_scp_event( void ) {
       baro_scp_pressure |= scp_trans.buf[1];
       baro_scp_pressure *= 25;
 
+#ifdef SENSOR_SYNC_SEND
       DOWNLINK_SEND_SCP_STATUS(DefaultChannel, &baro_scp_pressure, &baro_scp_temperature);
+#endif
 
       baro_scp_status = BARO_SCP_IDLE;
     }