Merged ETS airspeed driver

13 files changed, 1126 insertions, 62 deletions

diff --git a/src/drivers/drv_airspeed.h b/src/drivers/drv_airspeed.h
new file mode 100644
index 000000000..bffc35c62
--- /dev/null
+++ b/src/drivers/drv_airspeed.h
@@ -0,0 +1,61 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file Airspeed driver interface.
+ * @author Simon Wilks
+ */
+
+#ifndef _DRV_AIRSPEED_H
+#define _DRV_AIRSPEED_H
+
+#include <stdint.h>
+#include <sys/ioctl.h>
+
+#include "drv_sensor.h"
+#include "drv_orb_dev.h"
+
+#define AIRSPEED_DEVICE_PATH	"/dev/airspeed"
+
+/*
+ * ioctl() definitions
+ *
+ * Airspeed drivers also implement the generic sensor driver
+ * interfaces from drv_sensor.h
+ */
+
+#define _AIRSPEEDIOCBASE		(0x7700)
+#define __AIRSPEEDIOC(_n)		(_IOC(_AIRSPEEDIOCBASE, _n))
+
+
+#endif /* _DRV_AIRSPEED_H */
diff --git a/src/drivers/ets_airspeed/ets_airspeed.cpp b/src/drivers/ets_airspeed/ets_airspeed.cpp
new file mode 100644
index 000000000..e50395e47
--- /dev/null
+++ b/src/drivers/ets_airspeed/ets_airspeed.cpp
@@ -0,0 +1,832 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file ets_airspeed.cpp
+ * @author Simon Wilks
+ *
+ * Driver for the Eagle Tree Airspeed V3 connected via I2C.
+ */
+	 
+#include <nuttx/config.h>
+
+#include <drivers/device/i2c.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <semaphore.h>
+#include <string.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <errno.h>
+#include <stdio.h>
+#include <math.h>
+#include <unistd.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/clock.h>
+
+#include <arch/board/board.h>
+
+#include <systemlib/airspeed.h>
+#include <systemlib/err.h>
+#include <systemlib/param/param.h>
+#include <systemlib/perf_counter.h>
+
+#include <drivers/drv_airspeed.h>
+#include <drivers/drv_hrt.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/differential_pressure.h>
+#include <uORB/topics/subsystem_info.h>
+
+/* Default I2C bus */
+#define PX4_I2C_BUS_DEFAULT		PX4_I2C_BUS_EXPANSION
+
+/* I2C bus address */
+#define I2C_ADDRESS		0x75	/* 7-bit address. 8-bit address is 0xEA */
+
+/* Register address */
+#define READ_CMD		0x07		/* Read the data */
+	 
+/**
+ * The Eagle Tree Airspeed V3 cannot provide accurate reading below speeds of 15km/h. 
+ */
+#define MIN_ACCURATE_DIFF_PRES_PA 12
+
+/* Measurement rate is 100Hz */
+#define CONVERSION_INTERVAL	(1000000 / 100)	/* microseconds */
+
+/* Oddly, ERROR is not defined for C++ */
+#ifdef ERROR
+# undef ERROR
+#endif
+static const int ERROR = -1;
+
+#ifndef CONFIG_SCHED_WORKQUEUE
+# error This requires CONFIG_SCHED_WORKQUEUE.
+#endif
+
+class ETSAirspeed : public device::I2C
+{
+public:
+	ETSAirspeed(int bus, int address = I2C_ADDRESS);
+	virtual ~ETSAirspeed();
+	
+	virtual int 		init();
+	
+	virtual ssize_t		read(struct file *filp, char *buffer, size_t buflen);
+	virtual int			ioctl(struct file *filp, int cmd, unsigned long arg);
+	
+	/**
+	 * Diagnostics - print some basic information about the driver.
+	 */
+	void				print_info();
+	
+protected:
+	virtual int			probe();
+
+private:
+	work_s						_work;
+	unsigned					_num_reports;
+	volatile unsigned			_next_report;
+	volatile unsigned			_oldest_report;
+	differential_pressure_s		*_reports;
+	bool						_sensor_ok;
+	int							_measure_ticks;
+	bool						_collect_phase;
+	int 						_diff_pres_offset;
+	
+	orb_advert_t				_airspeed_pub;
+
+	perf_counter_t				_sample_perf;
+	perf_counter_t				_comms_errors;
+	perf_counter_t				_buffer_overflows;
+
+	
+	/**
+	* Test whether the device supported by the driver is present at a
+	* specific address.
+	*
+	* @param address	The I2C bus address to probe.
+	* @return		True if the device is present.
+	*/
+	int					probe_address(uint8_t address);
+	
+	/**
+	* Initialise the automatic measurement state machine and start it.
+	*
+	* @note This function is called at open and error time.  It might make sense
+	*       to make it more aggressive about resetting the bus in case of errors.
+	*/
+	void				start();
+	
+	/**
+	* Stop the automatic measurement state machine.
+	*/
+	void				stop();
+	
+	/**
+	* Perform a poll cycle; collect from the previous measurement
+	* and start a new one.
+	*/
+	void				cycle();
+	int					measure();
+	int					collect();
+
+	/**
+	* Static trampoline from the workq context; because we don't have a
+	* generic workq wrapper yet.
+	*
+	* @param arg		Instance pointer for the driver that is polling.
+	*/
+	static void		cycle_trampoline(void *arg);
+	
+	
+};
+
+/* helper macro for handling report buffer indices */
+#define INCREMENT(_x, _lim)	do { _x++; if (_x >= _lim) _x = 0; } while(0)
+
+/*
+ * Driver 'main' command.
+ */
+extern "C" __EXPORT int ets_airspeed_main(int argc, char *argv[]);
+
+ETSAirspeed::ETSAirspeed(int bus, int address) :
+	I2C("ETSAirspeed", AIRSPEED_DEVICE_PATH, bus, address, 100000),
+	_num_reports(0),
+	_next_report(0),
+	_oldest_report(0),
+	_reports(nullptr),
+	_sensor_ok(false),
+	_measure_ticks(0),
+	_collect_phase(false),
+	_diff_pres_offset(0),
+	_airspeed_pub(-1),
+	_sample_perf(perf_alloc(PC_ELAPSED, "ets_airspeed_read")),
+	_comms_errors(perf_alloc(PC_COUNT, "ets_airspeed_comms_errors")),
+	_buffer_overflows(perf_alloc(PC_COUNT, "ets_airspeed_buffer_overflows"))
+{
+	// enable debug() calls
+	_debug_enabled = true;
+	
+	// work_cancel in the dtor will explode if we don't do this...
+	memset(&_work, 0, sizeof(_work));
+}
+
+ETSAirspeed::~ETSAirspeed()
+{
+	/* make sure we are truly inactive */
+	stop();
+
+	/* free any existing reports */
+	if (_reports != nullptr)
+		delete[] _reports;
+}
+
+int
+ETSAirspeed::init()
+{
+	int ret = ERROR;
+
+	/* do I2C init (and probe) first */
+	if (I2C::init() != OK)
+		goto out;
+
+	/* allocate basic report buffers */
+	_num_reports = 2;
+	_reports = new struct differential_pressure_s[_num_reports];
+	for (unsigned i = 0; i < _num_reports; i++)
+		_reports[i].max_differential_pressure_pa = 0;
+
+	if (_reports == nullptr)
+		goto out;
+
+	_oldest_report = _next_report = 0;
+
+	/* get a publish handle on the airspeed topic */
+	memset(&_reports[0], 0, sizeof(_reports[0]));
+	_airspeed_pub = orb_advertise(ORB_ID(differential_pressure), &_reports[0]);
+
+	if (_airspeed_pub < 0)
+		debug("failed to create airspeed sensor object. Did you start uOrb?");
+
+	ret = OK;
+	/* sensor is ok, but we don't really know if it is within range */
+	_sensor_ok = true;
+out:
+	return ret;
+}
+
+int
+ETSAirspeed::probe()
+{
+	return measure();
+}
+
+int
+ETSAirspeed::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+
+	case SENSORIOCSPOLLRATE: {
+			switch (arg) {
+
+				/* switching to manual polling */
+			case SENSOR_POLLRATE_MANUAL:
+				stop();
+				_measure_ticks = 0;
+				return OK;
+
+				/* external signalling (DRDY) not supported */
+			case SENSOR_POLLRATE_EXTERNAL:
+
+				/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+				/* set default/max polling rate */
+			case SENSOR_POLLRATE_MAX:
+			case SENSOR_POLLRATE_DEFAULT: {
+					/* do we need to start internal polling? */
+					bool want_start = (_measure_ticks == 0);
+
+					/* set interval for next measurement to minimum legal value */
+					_measure_ticks = USEC2TICK(CONVERSION_INTERVAL);
+
+					/* if we need to start the poll state machine, do it */
+					if (want_start)
+						start();
+
+					return OK;
+				}
+
+				/* adjust to a legal polling interval in Hz */
+			default: {
+					/* do we need to start internal polling? */
+					bool want_start = (_measure_ticks == 0);
+
+					/* convert hz to tick interval via microseconds */
+					unsigned ticks = USEC2TICK(1000000 / arg);
+
+					/* check against maximum rate */
+					if (ticks < USEC2TICK(CONVERSION_INTERVAL))
+						return -EINVAL;
+
+					/* update interval for next measurement */
+					_measure_ticks = ticks;
+
+					/* if we need to start the poll state machine, do it */
+					if (want_start)
+						start();
+
+					return OK;
+				}
+			}
+		}
+
+	case SENSORIOCGPOLLRATE:
+		if (_measure_ticks == 0)
+			return SENSOR_POLLRATE_MANUAL;
+
+		return (1000 / _measure_ticks);
+
+	case SENSORIOCSQUEUEDEPTH: {
+			/* add one to account for the sentinel in the ring */
+			arg++;
+
+			/* lower bound is mandatory, upper bound is a sanity check */
+			if ((arg < 2) || (arg > 100))
+				return -EINVAL;
+
+			/* allocate new buffer */
+			struct differential_pressure_s *buf = new struct differential_pressure_s[arg];
+
+			if (nullptr == buf)
+				return -ENOMEM;
+
+			/* reset the measurement state machine with the new buffer, free the old */
+			stop();
+			delete[] _reports;
+			_num_reports = arg;
+			_reports = buf;
+			start();
+
+			return OK;
+		}
+
+	case SENSORIOCGQUEUEDEPTH:
+		return _num_reports - 1;
+		
+	case SENSORIOCRESET:
+		/* XXX implement this */
+		return -EINVAL;
+	
+	default:
+		/* give it to the superclass */
+		return I2C::ioctl(filp, cmd, arg);
+	}
+}
+
+ssize_t
+ETSAirspeed::read(struct file *filp, char *buffer, size_t buflen)
+{
+	unsigned count = buflen / sizeof(struct differential_pressure_s);
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (count < 1)
+		return -ENOSPC;
+
+	/* if automatic measurement is enabled */
+	if (_measure_ticks > 0) {
+
+		/*
+		 * While there is space in the caller's buffer, and reports, copy them.
+		 * Note that we may be pre-empted by the workq thread while we are doing this;
+		 * we are careful to avoid racing with them.
+		 */
+		while (count--) {
+			if (_oldest_report != _next_report) {
+				memcpy(buffer, _reports + _oldest_report, sizeof(*_reports));
+				ret += sizeof(_reports[0]);
+				INCREMENT(_oldest_report, _num_reports);
+			}
+		}
+
+		/* if there was no data, warn the caller */
+		return ret ? ret : -EAGAIN;
+	}
+
+	/* manual measurement - run one conversion */
+	/* XXX really it'd be nice to lock against other readers here */
+	do {
+		_oldest_report = _next_report = 0;
+
+		/* trigger a measurement */
+		if (OK != measure()) {
+			ret = -EIO;
+			break;
+		}
+
+		/* wait for it to complete */
+		usleep(CONVERSION_INTERVAL);
+
+		/* run the collection phase */
+		if (OK != collect()) {
+			ret = -EIO;
+			break;
+		}
+
+		/* state machine will have generated a report, copy it out */
+		memcpy(buffer, _reports, sizeof(*_reports));
+		ret = sizeof(*_reports);
+
+	} while (0);
+
+	return ret;
+}
+
+int
+ETSAirspeed::measure()
+{
+	int ret;
+
+	/*
+	 * Send the command to begin a measurement.
+	 */
+	uint8_t cmd = READ_CMD;
+	ret = transfer(&cmd, 1, nullptr, 0);
+
+	if (OK != ret)
+	{
+		perf_count(_comms_errors);
+		log("i2c::transfer returned %d", ret);
+		return ret;
+	}
+	ret = OK;
+	
+	return ret;
+}
+
+int
+ETSAirspeed::collect()
+{
+	int	ret = -EIO;
+	
+	/* read from the sensor */
+	uint8_t val[2] = {0, 0};
+	
+	perf_begin(_sample_perf);
+	
+	ret = transfer(nullptr, 0, &val[0], 2);
+	
+	if (ret < 0) {
+		log("error reading from sensor: %d", ret);
+		return ret;
+	}
+	
+	uint16_t diff_pres_pa = val[1] << 8 | val[0];
+
+	param_get(param_find("SENS_DPRES_OFF"), &_diff_pres_offset);
+	
+	if (diff_pres_pa < _diff_pres_offset + MIN_ACCURATE_DIFF_PRES_PA) { 
+		diff_pres_pa = 0;
+	} else {
+		diff_pres_pa -= _diff_pres_offset;	
+	}
+
+    // XXX we may want to smooth out the readings to remove noise.
+
+	_reports[_next_report].timestamp = hrt_absolute_time();
+	_reports[_next_report].differential_pressure_pa = diff_pres_pa;
+
+	// Track maximum differential pressure measured (so we can work out top speed).
+	if (diff_pres_pa > _reports[_next_report].max_differential_pressure_pa) {
+		_reports[_next_report].max_differential_pressure_pa = diff_pres_pa;
+	}
+
+	/* announce the airspeed if needed, just publish else */
+	orb_publish(ORB_ID(differential_pressure), _airspeed_pub, &_reports[_next_report]);
+
+	/* post a report to the ring - note, not locked */
+	INCREMENT(_next_report, _num_reports);
+
+	/* if we are running up against the oldest report, toss it */
+	if (_next_report == _oldest_report) {
+		perf_count(_buffer_overflows);
+		INCREMENT(_oldest_report, _num_reports);
+	}
+
+	/* notify anyone waiting for data */
+	poll_notify(POLLIN);
+
+	ret = OK;
+
+	perf_end(_sample_perf);
+	
+	return ret;
+}
+
+void
+ETSAirspeed::start()
+{
+	/* reset the report ring and state machine */
+	_collect_phase = false;
+	_oldest_report = _next_report = 0;
+
+	/* schedule a cycle to start things */
+	work_queue(HPWORK, &_work, (worker_t)&ETSAirspeed::cycle_trampoline, this, 1);
+	
+	/* notify about state change */
+	struct subsystem_info_s info = {
+		true,
+		true,
+		true,
+		SUBSYSTEM_TYPE_DIFFPRESSURE};
+	static orb_advert_t pub = -1;
+
+	if (pub > 0) {
+		orb_publish(ORB_ID(subsystem_info), pub, &info);
+	} else {
+		pub = orb_advertise(ORB_ID(subsystem_info), &info);
+	}
+}
+
+void
+ETSAirspeed::stop()
+{
+	work_cancel(HPWORK, &_work);
+}
+
+void
+ETSAirspeed::cycle_trampoline(void *arg)
+{
+	ETSAirspeed *dev = (ETSAirspeed *)arg;
+
+	dev->cycle();
+}
+
+void
+ETSAirspeed::cycle()
+{
+	/* collection phase? */
+	if (_collect_phase) {
+
+		/* perform collection */
+		if (OK != collect()) {
+			log("collection error");
+			/* restart the measurement state machine */
+			start();
+			return;
+		}
+
+		/* next phase is measurement */
+		_collect_phase = false;
+
+		/*
+		 * Is there a collect->measure gap?
+		 */
+		if (_measure_ticks > USEC2TICK(CONVERSION_INTERVAL)) {
+
+			/* schedule a fresh cycle call when we are ready to measure again */
+			work_queue(HPWORK,
+				   &_work,
+				   (worker_t)&ETSAirspeed::cycle_trampoline,
+				   this,
+				   _measure_ticks - USEC2TICK(CONVERSION_INTERVAL));
+
+			return;
+		}
+	}
+
+	/* measurement phase */
+	if (OK != measure())
+		log("measure error");
+
+	/* next phase is collection */
+	_collect_phase = true;
+
+	/* schedule a fresh cycle call when the measurement is done */
+	work_queue(HPWORK,
+		   &_work,
+		   (worker_t)&ETSAirspeed::cycle_trampoline,
+		   this,
+		   USEC2TICK(CONVERSION_INTERVAL));
+}
+
+void
+ETSAirspeed::print_info()
+{
+	perf_print_counter(_sample_perf);
+	perf_print_counter(_comms_errors);
+	perf_print_counter(_buffer_overflows);
+	printf("poll interval:  %u ticks\n", _measure_ticks);
+	printf("report queue:   %u (%u/%u @ %p)\n",
+	       _num_reports, _oldest_report, _next_report, _reports);
+}
+
+/**
+ * Local functions in support of the shell command.
+ */
+namespace ets_airspeed
+{
+
+/* oddly, ERROR is not defined for c++ */
+#ifdef ERROR
+# undef ERROR
+#endif
+const int ERROR = -1;
+
+ETSAirspeed	*g_dev;
+
+void	start(int i2c_bus);
+void	stop();
+void	test();
+void	reset();
+void	info();
+
+/**
+ * Start the driver.
+ */
+void
+start(int i2c_bus)
+{
+	int fd;
+
+	if (g_dev != nullptr)
+		errx(1, "already started");
+
+	/* create the driver */
+	g_dev = new ETSAirspeed(i2c_bus);
+
+	if (g_dev == nullptr)
+		goto fail;
+
+	if (OK != g_dev->init())
+		goto fail;
+
+	/* set the poll rate to default, starts automatic data collection */
+	fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0)
+		goto fail;
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0)
+		goto fail;
+
+	exit(0);
+
+fail:
+
+	if (g_dev != nullptr) 
+	{
+		delete g_dev;
+		g_dev = nullptr;
+	}
+
+	errx(1, "driver start failed");
+}
+
+/**
+ * Stop the driver
+ */
+void
+stop()
+{
+	if (g_dev != nullptr)
+	{
+		delete g_dev;
+		g_dev = nullptr;
+	}
+	else
+	{
+		errx(1, "driver not running");
+	}
+	exit(0);
+}
+
+/**
+ * Perform some basic functional tests on the driver;
+ * make sure we can collect data from the sensor in polled
+ * and automatic modes.
+ */
+void
+test()
+{
+	struct differential_pressure_s report;
+	ssize_t sz;
+	int ret;
+
+	int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0)
+		err(1, "%s open failed (try 'ets_airspeed start' if the driver is not running", AIRSPEED_DEVICE_PATH);
+
+	/* do a simple demand read */
+	sz = read(fd, &report, sizeof(report));
+
+	if (sz != sizeof(report))
+		err(1, "immediate read failed");
+
+	warnx("single read");
+	warnx("diff pressure: %d pa", report.differential_pressure_pa);
+
+	/* start the sensor polling at 2Hz */
+	if (OK != ioctl(fd, SENSORIOCSPOLLRATE, 2))
+		errx(1, "failed to set 2Hz poll rate");
+
+	/* read the sensor 5x and report each value */
+	for (unsigned i = 0; i < 5; i++) {
+		struct pollfd fds;
+
+		/* wait for data to be ready */
+		fds.fd = fd;
+		fds.events = POLLIN;
+		ret = poll(&fds, 1, 2000);
+
+		if (ret != 1)
+			errx(1, "timed out waiting for sensor data");
+
+		/* now go get it */
+		sz = read(fd, &report, sizeof(report));
+
+		if (sz != sizeof(report))
+			err(1, "periodic read failed");
+
+		warnx("periodic read %u", i);
+		warnx("diff pressure: %d pa", report.differential_pressure_pa);
+	}
+
+	errx(0, "PASS");
+}
+
+/**
+ * Reset the driver.
+ */
+void
+reset()
+{
+	int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0)
+		err(1, "failed ");
+
+	if (ioctl(fd, SENSORIOCRESET, 0) < 0)
+		err(1, "driver reset failed");
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0)
+		err(1, "driver poll restart failed");
+
+	exit(0);
+}
+
+/**
+ * Print a little info about the driver.
+ */
+void
+info()
+{
+	if (g_dev == nullptr)
+		errx(1, "driver not running");
+
+	printf("state @ %p\n", g_dev);
+	g_dev->print_info();
+
+	exit(0);
+}
+
+} // namespace
+
+
+static void 
+ets_airspeed_usage() 
+{
+	fprintf(stderr, "usage: ets_airspeed [options] command\n");
+	fprintf(stderr, "options:\n");
+	fprintf(stderr, "\t-b --bus i2cbus (%d)\n", PX4_I2C_BUS_DEFAULT);
+	fprintf(stderr, "command:\n");
+	fprintf(stderr, "\tstart|stop|reset|test|info\n");
+}
+
+int
+ets_airspeed_main(int argc, char *argv[])
+{
+	int i2c_bus = PX4_I2C_BUS_DEFAULT;
+
+	int i;
+	for (i = 1; i < argc; i++) {
+		if (strcmp(argv[i], "-b") == 0 || strcmp(argv[i], "--bus") == 0) {
+			if (argc > i + 1) {
+				i2c_bus = atoi(argv[i + 1]);
+			}
+		}
+	}
+
+	/*
+	 * Start/load the driver.
+	 */
+	if (!strcmp(argv[1], "start"))
+		ets_airspeed::start(i2c_bus);
+	
+	 /*
+	  * Stop the driver
+	  */
+	 if (!strcmp(argv[1], "stop"))
+		 ets_airspeed::stop();
+
+	/*
+	 * Test the driver/device.
+	 */
+	if (!strcmp(argv[1], "test"))
+		ets_airspeed::test();
+
+	/*
+	 * Reset the driver.
+	 */
+	if (!strcmp(argv[1], "reset"))
+		ets_airspeed::reset();
+
+	/*
+	 * Print driver information.
+	 */
+	if (!strcmp(argv[1], "info") || !strcmp(argv[1], "status"))
+		ets_airspeed::info();
+
+	ets_airspeed_usage();
+	exit(0);
+}
diff --git a/src/drivers/ets_airspeed/module.mk b/src/drivers/ets_airspeed/module.mk
new file mode 100644
index 000000000..cb5d3b1ed
--- /dev/null
+++ b/src/drivers/ets_airspeed/module.mk
@@ -0,0 +1,41 @@
+############################################################################
+#
+#   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+#
+# Makefile to build the Eagle Tree Airspeed V3 driver.
+#
+
+MODULE_COMMAND		= ets_airspeed
+MODULE_STACKSIZE	= 1024
+
+SRCS			= ets_airspeed.cpp
diff --git a/src/drivers/hott_telemetry/messages.c b/src/drivers/hott_telemetry/messages.c
index 5fbee16ce..f0f32d244 100644
--- a/src/drivers/hott_telemetry/messages.c
+++ b/src/drivers/hott_telemetry/messages.c
@@ -42,9 +42,11 @@
 #include <string.h>
 #include <systemlib/systemlib.h>
 #include <unistd.h>
+#include <uORB/topics/airspeed.h>
 #include <uORB/topics/battery_status.h>
 #include <uORB/topics/sensor_combined.h>
 
+static int airspeed_sub = -1;
 static int battery_sub = -1;
 static int sensor_sub = -1;
 
@@ -52,6 +54,7 @@ void messages_init(void)
 {
 	battery_sub = orb_subscribe(ORB_ID(battery_status));
 	sensor_sub = orb_subscribe(ORB_ID(sensor_combined));
+	airspeed_sub = orb_subscribe(ORB_ID(airspeed));
 }
 
 void build_eam_response(uint8_t *buffer, int *size)
@@ -81,6 +84,15 @@ void build_eam_response(uint8_t *buffer, int *size)
 	msg.altitude_L = (uint8_t)alt & 0xff;
 	msg.altitude_H = (uint8_t)(alt >> 8) & 0xff;
 
+	/* get a local copy of the current sensor values */
+	struct airspeed_s airspeed;
+	memset(&airspeed, 0, sizeof(airspeed));
+	orb_copy(ORB_ID(airspeed), airspeed_sub, &airspeed);
+
+	uint16_t speed = (uint16_t)(airspeed.indicated_airspeed_m_s * 3.6);
+	msg.speed_L = (uint8_t)speed & 0xff;
+	msg.speed_H = (uint8_t)(speed >> 8) & 0xff;
+
 	msg.stop = STOP_BYTE;
 
 	memcpy(buffer, &msg, *size);
diff --git a/src/modules/commander/commander.c b/src/modules/commander/commander.c
index 0f18d6cef..01ab9e3d9 100644
--- a/src/modules/commander/commander.c
+++ b/src/modules/commander/commander.c
@@ -676,22 +676,22 @@ void do_airspeed_calibration(int status_pub, struct vehicle_status_s *status)
 
 	const int calibration_count = 2500;
 
-	int sub_differential_pressure = orb_subscribe(ORB_ID(differential_pressure));
-	struct differential_pressure_s differential_pressure;
+	int diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
+	struct differential_pressure_s diff_pres;
 
 	int calibration_counter = 0;
-	float airspeed_offset = 0.0f;
+	float diff_pres_offset = 0.0f;
 
 	while (calibration_counter < calibration_count) {
 
 		/* wait blocking for new data */
-		struct pollfd fds[1] = { { .fd = sub_differential_pressure, .events = POLLIN } };
+		struct pollfd fds[1] = { { .fd = diff_pres_sub, .events = POLLIN } };
 
 		int poll_ret = poll(fds, 1, 1000);
 
 		if (poll_ret) {
-			orb_copy(ORB_ID(differential_pressure), sub_differential_pressure, &differential_pressure);
-			airspeed_offset += differential_pressure.voltage;
+			orb_copy(ORB_ID(differential_pressure), diff_pres_sub, &diff_pres);
+			diff_pres_offset += diff_pres.differential_pressure_pa;
 			calibration_counter++;
 
 		} else if (poll_ret == 0) {
@@ -701,11 +701,11 @@ void do_airspeed_calibration(int status_pub, struct vehicle_status_s *status)
 		}
 	}
 
-	airspeed_offset = airspeed_offset / calibration_count;
+	diff_pres_offset = diff_pres_offset / calibration_count;
 
-	if (isfinite(airspeed_offset)) {
+	if (isfinite(diff_pres_offset)) {
 
-		if (param_set(param_find("SENS_VAIR_OFF"), &(airspeed_offset))) {
+		if (param_set(param_find("SENS_DPRES_OFF"), &(diff_pres_offset))) {
 			mavlink_log_critical(mavlink_fd, "Setting offs failed!");
 		}
 
@@ -735,7 +735,7 @@ void do_airspeed_calibration(int status_pub, struct vehicle_status_s *status)
 	status->flag_preflight_airspeed_calibration = false;
 	state_machine_publish(status_pub, status, mavlink_fd);
 
-	close(sub_differential_pressure);
+	close(diff_pres_sub);
 }
 
 
@@ -1356,10 +1356,10 @@ int commander_thread_main(int argc, char *argv[])
 	struct sensor_combined_s sensors;
 	memset(&sensors, 0, sizeof(sensors));
 
-	int differential_pressure_sub = orb_subscribe(ORB_ID(differential_pressure));
-	struct differential_pressure_s differential_pressure;
-	memset(&differential_pressure, 0, sizeof(differential_pressure));
-	uint64_t last_differential_pressure_time = 0;
+	int diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
+	struct differential_pressure_s diff_pres;
+	memset(&diff_pres, 0, sizeof(diff_pres));
+	uint64_t last_diff_pres_time = 0;
 
 	/* Subscribe to command topic */
 	int cmd_sub = orb_subscribe(ORB_ID(vehicle_command));
@@ -1414,11 +1414,11 @@ int commander_thread_main(int argc, char *argv[])
 			orb_copy(ORB_ID(sensor_combined), sensor_sub, &sensors);
 		}
 
-		orb_check(differential_pressure_sub, &new_data);
+		orb_check(diff_pres_sub, &new_data);
 
 		if (new_data) {
-			orb_copy(ORB_ID(differential_pressure), differential_pressure_sub, &differential_pressure);
-			last_differential_pressure_time = differential_pressure.timestamp;
+			orb_copy(ORB_ID(differential_pressure), diff_pres_sub, &diff_pres);
+			last_diff_pres_time = diff_pres.timestamp;
 		}
 
 		orb_check(cmd_sub, &new_data);
@@ -1633,7 +1633,7 @@ int commander_thread_main(int argc, char *argv[])
 		}
 
 		/* Check for valid airspeed/differential pressure measurements */
-		if (hrt_absolute_time() - last_differential_pressure_time < 2000000) {
+		if (hrt_absolute_time() - last_diff_pres_time < 2000000) {
 			current_status.flag_airspeed_valid = true;
 
 		} else {
diff --git a/src/modules/sdlog/sdlog.c b/src/modules/sdlog/sdlog.c
index df8745d9f..84a9eb6ac 100644
--- a/src/modules/sdlog/sdlog.c
+++ b/src/modules/sdlog/sdlog.c
@@ -71,6 +71,7 @@
 #include <uORB/topics/optical_flow.h>
 #include <uORB/topics/battery_status.h>
 #include <uORB/topics/differential_pressure.h>
+#include <uORB/topics/airspeed.h>
 
 #include <systemlib/systemlib.h>
 
@@ -443,7 +444,8 @@ int sdlog_thread_main(int argc, char *argv[])
 		struct vehicle_vicon_position_s vicon_pos;
 		struct optical_flow_s flow;
 		struct battery_status_s batt;
-		struct differential_pressure_s diff_pressure;
+		struct differential_pressure_s diff_pres;
+		struct airspeed_s airspeed;
 	} buf;
 	memset(&buf, 0, sizeof(buf));
 
@@ -461,7 +463,8 @@ int sdlog_thread_main(int argc, char *argv[])
 		int vicon_pos_sub;
 		int flow_sub;
 		int batt_sub;
-		int diff_pressure_sub;
+		int diff_pres_sub;
+		int airspeed_sub;
 	} subs;
 
 	/* --- MANAGEMENT - LOGGING COMMAND --- */
@@ -558,11 +561,18 @@ int sdlog_thread_main(int argc, char *argv[])
 
 	/* --- DIFFERENTIAL PRESSURE --- */
 	/* subscribe to ORB for flow measurements */
-	subs.diff_pressure_sub = orb_subscribe(ORB_ID(differential_pressure));
-	fds[fdsc_count].fd = subs.diff_pressure_sub;
+	subs.diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
+	fds[fdsc_count].fd = subs.diff_pres_sub;
 	fds[fdsc_count].events = POLLIN;
 	fdsc_count++;
 
+	/* --- AIRSPEED --- */
+	/* subscribe to ORB for airspeed */
+	subs.airspeed_sub = orb_subscribe(ORB_ID(airspeed));
+	fds[fdsc_count].fd = subs.airspeed_sub;
+	fds[fdsc_count].events = POLLIN;
+	fdsc_count++;	
+
 	/* WARNING: If you get the error message below,
 	 * then the number of registered messages (fdsc)
 	 * differs from the number of messages in the above list.
@@ -654,7 +664,8 @@ int sdlog_thread_main(int argc, char *argv[])
 				orb_copy(ORB_ID(vehicle_attitude), subs.att_sub, &buf.att);
 				orb_copy(ORB_ID(vehicle_vicon_position), subs.vicon_pos_sub, &buf.vicon_pos);
 				orb_copy(ORB_ID(optical_flow), subs.flow_sub, &buf.flow);
-				orb_copy(ORB_ID(differential_pressure), subs.diff_pressure_sub, &buf.diff_pressure);
+				orb_copy(ORB_ID(differential_pressure), subs.diff_pres_sub, &buf.diff_pres);
+				orb_copy(ORB_ID(airspeed), subs.airspeed_sub, &buf.airspeed);
 				orb_copy(ORB_ID(battery_status), subs.batt_sub, &buf.batt);
 
 				/* if skipping is on or logging is disabled, ignore */
@@ -691,9 +702,9 @@ int sdlog_thread_main(int argc, char *argv[])
 					.vicon = {buf.vicon_pos.x, buf.vicon_pos.y, buf.vicon_pos.z, buf.vicon_pos.roll, buf.vicon_pos.pitch, buf.vicon_pos.yaw},
 					.control_effective = {buf.act_controls_effective.control_effective[0], buf.act_controls_effective.control_effective[1], buf.act_controls_effective.control_effective[2], buf.act_controls_effective.control_effective[3]},
 					.flow = {buf.flow.flow_raw_x, buf.flow.flow_raw_y, buf.flow.flow_comp_x_m, buf.flow.flow_comp_y_m, buf.flow.ground_distance_m, buf.flow.quality},
-					.diff_pressure = buf.diff_pressure.differential_pressure_mbar,
-					.ind_airspeed = buf.diff_pressure.indicated_airspeed_m_s,
-					.true_airspeed = buf.diff_pressure.true_airspeed_m_s
+					.diff_pressure = buf.diff_pres.differential_pressure_pa,
+					.ind_airspeed = buf.airspeed.indicated_airspeed_m_s,
+					.true_airspeed = buf.airspeed.true_airspeed_m_s
 				};
 
 				/* put into buffer for later IO */
diff --git a/src/modules/sensors/sensor_params.c b/src/modules/sensors/sensor_params.c
index c850e3a1e..230060148 100644
--- a/src/modules/sensors/sensor_params.c
+++ b/src/modules/sensors/sensor_params.c
@@ -64,7 +64,7 @@ PARAM_DEFINE_FLOAT(SENS_ACC_XSCALE, 1.0f);
 PARAM_DEFINE_FLOAT(SENS_ACC_YSCALE, 1.0f);
 PARAM_DEFINE_FLOAT(SENS_ACC_ZSCALE, 1.0f);
 
-PARAM_DEFINE_FLOAT(SENS_VAIR_OFF, 2.5f);
+PARAM_DEFINE_INT32(SENS_DPRES_OFF, 1667);
 
 PARAM_DEFINE_FLOAT(RC1_MIN, 1000.0f);
 PARAM_DEFINE_FLOAT(RC1_TRIM, 1500.0f);
diff --git a/src/modules/sensors/sensors.cpp b/src/modules/sensors/sensors.cpp
index 123bbb120..6b6aeedee 100644
--- a/src/modules/sensors/sensors.cpp
+++ b/src/modules/sensors/sensors.cpp
@@ -77,6 +77,7 @@
 #include <uORB/topics/parameter_update.h>
 #include <uORB/topics/battery_status.h>
 #include <uORB/topics/differential_pressure.h>
+#include <uORB/topics/airspeed.h>
 
 #define GYRO_HEALTH_COUNTER_LIMIT_ERROR 20   /* 40 ms downtime at 500 Hz update rate   */
 #define ACC_HEALTH_COUNTER_LIMIT_ERROR  20   /* 40 ms downtime at 500 Hz update rate   */
@@ -98,6 +99,12 @@
 #define BAT_VOL_LOWPASS_2 0.01f
 #define VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS 3.5f
 
+/**
+ * HACK - true temperature is much less than indicated temperature in baro,
+ * subtract 5 degrees in an attempt to account for the electrical upheating of the PCB
+ */
+#define PCB_TEMP_ESTIMATE_DEG 5.0f
+
 #define PPM_INPUT_TIMEOUT_INTERVAL	50000 /**< 50 ms timeout / 20 Hz */
 
 #define limit_minus_one_to_one(arg) (arg < -1.0f) ? -1.0f : ((arg > 1.0f) ? 1.0f : arg)
@@ -156,6 +163,8 @@ private:
 	int		_mag_sub;			/**< raw mag data subscription */
 	int 		_rc_sub;			/**< raw rc channels data subscription */
 	int		_baro_sub;			/**< raw baro data subscription */
+	int     _airspeed_sub;		/**< airspeed subscription */
+	int		_diff_pres_sub;		/**< raw differential pressure subscription */
 	int		_vstatus_sub;			/**< vehicle status subscription */
 	int 		_params_sub;			/**< notification of parameter updates */
 	int 		_manual_control_sub;			/**< notification of manual control updates */
@@ -165,13 +174,15 @@ private:
 	orb_advert_t	_rc_pub;			/**< raw r/c control topic */
 	orb_advert_t	_battery_pub;			/**< battery status */
 	orb_advert_t	_airspeed_pub;			/**< airspeed */
+	orb_advert_t	_diff_pres_pub;			/**< differential_pressure */
 
 	perf_counter_t	_loop_perf;			/**< loop performance counter */
 
 	struct rc_channels_s _rc;			/**< r/c channel data */
 	struct battery_status_s _battery_status;	/**< battery status */
 	struct baro_report _barometer;			/**< barometer data */
-	struct differential_pressure_s _differential_pressure;
+	struct differential_pressure_s _diff_pres;
+	struct airspeed_s _airspeed;
 
 	struct {
 		float min[_rc_max_chan_count];
@@ -187,7 +198,7 @@ private:
 		float mag_scale[3];
 		float accel_offset[3];
 		float accel_scale[3];
-		float airspeed_offset;
+		int diff_pres_offset_pa;
 
 		int rc_type;
 
@@ -236,7 +247,7 @@ private:
 		param_t accel_scale[3];
 		param_t mag_offset[3];
 		param_t mag_scale[3];
-		param_t airspeed_offset;
+		param_t diff_pres_offset_pa;
 
 		param_t rc_map_roll;
 		param_t rc_map_pitch;
@@ -331,6 +342,14 @@ private:
 	void		baro_poll(struct sensor_combined_s &raw);
 
 	/**
+	 * Poll the differential pressure sensor for updated data.
+	 *
+	 * @param raw			Combined sensor data structure into which
+	 *				data should be returned.
+	 */
+	void		diff_pres_poll(struct sensor_combined_s &raw);
+
+	/**
 	 * Check for changes in vehicle status.
 	 */
 	void		vehicle_status_poll();
@@ -400,6 +419,7 @@ Sensors::Sensors() :
 	_rc_pub(-1),
 	_battery_pub(-1),
 	_airspeed_pub(-1),
+	_diff_pres_pub(-1),
 
 /* performance counters */
 	_loop_perf(perf_alloc(PC_ELAPSED, "sensor task update"))
@@ -484,8 +504,8 @@ Sensors::Sensors() :
 	_parameter_handles.mag_scale[1] = param_find("SENS_MAG_YSCALE");
 	_parameter_handles.mag_scale[2] = param_find("SENS_MAG_ZSCALE");
 
-	/*Airspeed offset */
-	_parameter_handles.airspeed_offset = param_find("SENS_VAIR_OFF");
+	/* Differential pressure offset */
+	_parameter_handles.diff_pres_offset_pa = param_find("SENS_DPRES_OFF");
 
 	_parameter_handles.battery_voltage_scaling = param_find("BAT_V_SCALING");
 
@@ -695,7 +715,7 @@ Sensors::parameters_update()
 	param_get(_parameter_handles.mag_scale[2], &(_parameters.mag_scale[2]));
 
 	/* Airspeed offset */
-	param_get(_parameter_handles.airspeed_offset, &(_parameters.airspeed_offset));
+	param_get(_parameter_handles.diff_pres_offset_pa, &(_parameters.diff_pres_offset_pa));
 
 	/* scaling of ADC ticks to battery voltage */
 	if (param_get(_parameter_handles.battery_voltage_scaling, &(_parameters.battery_voltage_scaling)) != OK) {
@@ -890,6 +910,32 @@ Sensors::baro_poll(struct sensor_combined_s &raw)
 }
 
 void
+Sensors::diff_pres_poll(struct sensor_combined_s &raw)
+{
+	bool updated;
+	orb_check(_diff_pres_sub, &updated);
+
+	if (updated) {
+		orb_copy(ORB_ID(differential_pressure), _diff_pres_sub, &_diff_pres);
+
+		raw.differential_pressure_pa = _diff_pres.differential_pressure_pa;
+		raw.differential_pressure_counter++;
+
+		_airspeed.indicated_airspeed_m_s = calc_indicated_airspeed(_diff_pres.differential_pressure_pa);
+		_airspeed.true_airspeed_m_s = calc_true_airspeed(_diff_pres.differential_pressure_pa + raw.baro_pres_mbar*1e2f, 
+											 			 raw.baro_pres_mbar*1e2f, raw.baro_temp_celcius - PCB_TEMP_ESTIMATE_DEG);
+
+		/* announce the airspeed if needed, just publish else */
+		if (_airspeed_pub > 0) {
+			orb_publish(ORB_ID(airspeed), _airspeed_pub, &_airspeed);
+
+		} else {
+			_airspeed_pub = orb_advertise(ORB_ID(airspeed), &_airspeed);
+		}
+	}
+}
+
+void
 Sensors::vehicle_status_poll()
 {
 	struct vehicle_status_s vstatus;
@@ -1047,31 +1093,18 @@ Sensors::adc_poll(struct sensor_combined_s &raw)
 					 */
 					if (voltage > 0.4f) {
 
-						float diff_pres_pa = (voltage - _parameters.airspeed_offset) * 1000.0f; //for MPXV7002DP sensor
-
-						float airspeed_true = calc_true_airspeed(diff_pres_pa + _barometer.pressure*1e2f,
-							_barometer.pressure*1e2f, _barometer.temperature - 5.0f); //factor 1e2 for conversion from mBar to Pa
-						// XXX HACK - true temperature is much less than indicated temperature in baro,
-						// subtract 5 degrees in an attempt to account for the electrical upheating of the PCB
+						float diff_pres_pa = voltage * 1000.0f - _parameters.diff_pres_offset_pa; //for MPXV7002DP sensor
 
-						float airspeed_indicated = calc_indicated_airspeed(diff_pres_pa);
-
-						//printf("voltage: %.4f, diff_pres_pa %.4f, baro press %.4f Pa, v_ind %.4f, v_true %.4f\n", (double)voltage, (double)diff_pres_pa, (double)_barometer.pressure*1e2f, (double)airspeed_indicated, (double)airspeed_true);
-
-						_differential_pressure.timestamp = hrt_absolute_time();
-						_differential_pressure.static_pressure_mbar = _barometer.pressure;
-						_differential_pressure.differential_pressure_mbar = diff_pres_pa*1e-2f;
-						_differential_pressure.temperature_celcius = _barometer.temperature;
-						_differential_pressure.indicated_airspeed_m_s = airspeed_indicated;
-						_differential_pressure.true_airspeed_m_s = airspeed_true;
-						_differential_pressure.voltage = voltage;
+						_diff_pres.timestamp = hrt_absolute_time();
+						_diff_pres.differential_pressure_pa = diff_pres_pa;
+						_diff_pres.voltage = voltage;
 
 						/* announce the airspeed if needed, just publish else */
-						if (_airspeed_pub > 0) {
-							orb_publish(ORB_ID(differential_pressure), _airspeed_pub, &_differential_pressure);
+						if (_diff_pres_pub > 0) {
+							orb_publish(ORB_ID(differential_pressure), _diff_pres_pub, &_diff_pres);
 
 						} else {
-							_airspeed_pub = orb_advertise(ORB_ID(differential_pressure), &_differential_pressure);
+							_diff_pres_pub = orb_advertise(ORB_ID(differential_pressure), &_diff_pres);
 						}
 					}
 				}
@@ -1310,6 +1343,7 @@ Sensors::task_main()
 	_mag_sub = orb_subscribe(ORB_ID(sensor_mag));
 	_rc_sub = orb_subscribe(ORB_ID(input_rc));
 	_baro_sub = orb_subscribe(ORB_ID(sensor_baro));
+	_diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
 	_vstatus_sub = orb_subscribe(ORB_ID(vehicle_status));
 	_params_sub = orb_subscribe(ORB_ID(parameter_update));
 	_manual_control_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
@@ -1336,6 +1370,7 @@ Sensors::task_main()
 	gyro_poll(raw);
 	mag_poll(raw);
 	baro_poll(raw);
+	diff_pres_poll(raw);
 
 	parameter_update_poll(true /* forced */);
 
@@ -1384,6 +1419,8 @@ Sensors::task_main()
 		/* check battery voltage */
 		adc_poll(raw);
 
+		diff_pres_poll(raw);
+
 		/* Inform other processes that new data is available to copy */
 		if (_publishing)
 			orb_publish(ORB_ID(sensor_combined), _sensor_pub, &raw);
diff --git a/src/modules/systemlib/airspeed.c b/src/modules/systemlib/airspeed.c
index 264287b10..15bb833a9 100644
--- a/src/modules/systemlib/airspeed.c
+++ b/src/modules/systemlib/airspeed.c
@@ -97,7 +97,7 @@ float calc_true_airspeed(float total_pressure, float static_pressure, float temp
 	float density = get_air_density(static_pressure, temperature_celsius);
 	if (density < 0.0001f || !isfinite(density)) {
 	 density = CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C;
-	 printf("[airspeed] Invalid air density, using density at sea level\n");
+//	 printf("[airspeed] Invalid air density, using density at sea level\n");
 	}
 
 	float pressure_difference = total_pressure - static_pressure;
diff --git a/src/modules/uORB/objects_common.cpp b/src/modules/uORB/objects_common.cpp
index 136375140..4197f6fb2 100644
--- a/src/modules/uORB/objects_common.cpp
+++ b/src/modules/uORB/objects_common.cpp
@@ -122,6 +122,9 @@ ORB_DEFINE(optical_flow, struct optical_flow_s);
 #include "topics/omnidirectional_flow.h"
 ORB_DEFINE(omnidirectional_flow, struct omnidirectional_flow_s);
 
+#include "topics/airspeed.h"
+ORB_DEFINE(airspeed, struct airspeed_s);
+
 #include "topics/differential_pressure.h"
 ORB_DEFINE(differential_pressure, struct differential_pressure_s);
 
diff --git a/src/modules/uORB/topics/airspeed.h b/src/modules/uORB/topics/airspeed.h
new file mode 100644
index 000000000..a3da3758f
--- /dev/null
+++ b/src/modules/uORB/topics/airspeed.h
@@ -0,0 +1,67 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012-2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file airspeed.h
+ *
+ * Definition of airspeed topic
+ */
+
+#ifndef TOPIC_AIRSPEED_H_
+#define TOPIC_AIRSPEED_H_
+
+#include "../uORB.h"
+#include <stdint.h>
+
+/**
+ * @addtogroup topics
+ * @{
+ */
+
+/**
+ * Airspeed
+ */
+struct airspeed_s {
+	uint64_t	timestamp;					/**< microseconds since system boot, needed to integrate */
+	float		indicated_airspeed_m_s;		/**< indicated airspeed in meters per second, -1 if unknown	 */
+	float		true_airspeed_m_s;			/**< true airspeed in meters per second, -1 if unknown */
+};
+
+/**
+ * @}
+ */
+
+/* register this as object request broker structure */
+ORB_DECLARE(airspeed);
+
+#endif
diff --git a/src/modules/uORB/topics/differential_pressure.h b/src/modules/uORB/topics/differential_pressure.h
index d5e4bf37e..8ce85213b 100644
--- a/src/modules/uORB/topics/differential_pressure.h
+++ b/src/modules/uORB/topics/differential_pressure.h
@@ -49,16 +49,14 @@
  */
 
 /**
- * Differential pressure and airspeed
+ * Differential pressure.
  */
 struct differential_pressure_s {
-	uint64_t	timestamp;					/**< microseconds since system boot, needed to integrate */
-	float   	static_pressure_mbar;		/**< Static / environment pressure */
-	float		differential_pressure_mbar;	/**< Differential pressure reading */
-	float		temperature_celcius;		/**< ambient temperature in celcius, -1 if unknown */
-	float		indicated_airspeed_m_s;		/**< indicated airspeed in meters per second, -1 if unknown	 */
-	float		true_airspeed_m_s;			/**< true airspeed in meters per second, -1 if unknown */
-	float		voltage;					/**< Voltage from the airspeed sensor (voltage divider already compensated) */
+	uint64_t	timestamp;						/**< microseconds since system boot, needed to integrate */
+	uint16_t	differential_pressure_pa;		/**< Differential pressure reading */
+	uint16_t	max_differential_pressure_pa;	/**< Maximum differential pressure reading */
+	float		voltage;						/**< Voltage from analog airspeed sensors (voltage divider already compensated) */
+
 };
 
 /**
diff --git a/src/modules/uORB/topics/sensor_combined.h b/src/modules/uORB/topics/sensor_combined.h
index 961ee8b4a..9a76b5182 100644
--- a/src/modules/uORB/topics/sensor_combined.h
+++ b/src/modules/uORB/topics/sensor_combined.h
@@ -103,6 +103,8 @@ struct sensor_combined_s {
 	float mcu_temp_celcius;			/**< Internal temperature measurement of MCU */
 	uint32_t baro_counter;			/**< Number of raw baro measurements taken        */
 
+	float differential_pressure_pa;				/**< Airspeed sensor differential pressure                  */ 
+	uint32_t differential_pressure_counter;		/**< Number of raw differential pressure measurements taken */
 };
 
 /**