SHT3x driver

SHT3x driver, clean code
changes leading to merge TFHT with CUAV hygrometer
Delete humidity_temperature.msg
Update CMakeLists.txt
rename 'atmosphefir_quantities' to 'hygrometers'
fix logging
removed cmake files
fix PR issues

ROMFS/px4fmu_common/init.d/rc.sensors

@@ -130,6 +130,15 @@ then
 	fi
 fi
 
+# SHT3x temperature and hygrometer sensor, external I2C
+if param compare -s SENS_EN_SHT3X 1
+then
+	if ! sht3x start -X
+	then
+		sht3x start -X -a 0x45
+	fi
+fi
+
 # TE MS4525 differential pressure sensor external I2C
 if param compare -s SENS_EN_MS4525 1
 then

boards/px4/fmu-v5/default.px4board

@@ -15,6 +15,7 @@ CONFIG_COMMON_DISTANCE_SENSOR=y
 CONFIG_DRIVERS_DSHOT=y
 CONFIG_DRIVERS_GPS=y
 CONFIG_DRIVERS_HEATER=y
+CONFIG_HYGROMETERS=y
 CONFIG_DRIVERS_IMU_ANALOG_DEVICES_ADIS16448=y
 CONFIG_DRIVERS_IMU_BOSCH_BMI055=y
 CONFIG_DRIVERS_IMU_INVENSENSE_ICM20602=y
@@ -81,8 +82,8 @@ CONFIG_MODULES_UUV_ATT_CONTROL=y
 CONFIG_MODULES_UUV_POS_CONTROL=y
 CONFIG_MODULES_VMOUNT=y
 CONFIG_MODULES_VTOL_ATT_CONTROL=y
-CONFIG_SYSTEMCMDS_BL_UPDATE=y
 CONFIG_SYSTEMCMDS_ACTUATOR_TEST=y
+CONFIG_SYSTEMCMDS_BL_UPDATE=y
 CONFIG_SYSTEMCMDS_DMESG=y
 CONFIG_SYSTEMCMDS_DUMPFILE=y
 CONFIG_SYSTEMCMDS_GPIO=y

src/drivers/drv_sensor.h

@@ -198,6 +198,7 @@
 
 #define DRV_GPS_DEVTYPE_SIM 0xAF
 
+#define DRV_HYGRO_DEVTYPE_SHT3X 0xB1
 
 #define DRV_DEVTYPE_UNUSED		0xff
 

src/drivers/hygrometer/Kconfig

@@ -0,0 +1,9 @@
+menu "Hygrometers"
+    menuconfig HYGROMETERS
+        bool "Hygrometer sensors"
+        default n
+        select DRIVERS_HYGROMETER_SHT3x
+        ---help---
+            Enable default set of hygrometer sensors
+    rsource "*/Kconfig"
+endmenu #Hygrometers

src/drivers/hygrometer/sht3x/CMakeLists.txt

@@ -0,0 +1,43 @@
+############################################################################
+#
+#   Copyright (c) 2021 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.
+#
+############################################################################
+
+px4_add_module(
+	MODULE drivers__hygrometer__sht3x
+	MAIN sht3x
+	COMPILE_FLAGS
+	SRCS
+		sht3x.cpp
+		sht3x.h
+	DEPENDS
+		px4_work_queue
+	)

src/drivers/hygrometer/sht3x/Kconfig

@@ -0,0 +1,5 @@
+menuconfig DRIVERS_HYGROMETER_SHT3x
+	bool "SHT3x temperature and humidity sensor"
+	default n
+	---help---
+		Enable support SHT35 temperature/humidity sensor

src/drivers/hygrometer/sht3x/sht3x.cpp

@@ -0,0 +1,349 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 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 sht3x.c
+ *
+ * I2C driver for temperature/humidity sensor SHT3x by senserion
+ *
+ * @author Roman Dvorak <dvorakroman@thunderfly.cz>
+ *
+ */
+
+#include "sht3x.h"
+
+SHT3X::SHT3X(const I2CSPIDriverConfig &config) :
+	I2C(config),
+	ModuleParams(nullptr),
+	I2CSPIDriver(config)
+{
+}
+
+uint8_t SHT3X::calc_crc(uint8_t data[2])
+{
+	uint8_t crc = 0xFF;
+
+	for (int i = 0; i < 2; i++) {
+		crc ^= data[i];
+
+		for (uint8_t bit = 8; bit > 0; --bit) {
+			if (crc & 0x80) {
+				crc = (crc << 1) ^ 0x31u;
+
+			} else {
+				crc = (crc << 1);
+			}
+		}
+	}
+
+	return crc;
+}
+
+
+int SHT3X::set_pointer(uint16_t command)
+{
+	if (_last_command != command) {
+		uint8_t cmd[2];
+		cmd[0] = static_cast<uint8_t>(command >> 8);
+		cmd[1] = static_cast<uint8_t>(command & 0xff);
+		_last_command = command;
+		return transfer(&cmd[0], 2, nullptr, 0);
+
+	} else {
+		return 0;
+	}
+}
+
+int SHT3X::read_data(uint16_t command, uint8_t *data_ptr, uint8_t length)
+{
+	set_pointer(command);
+
+	uint8_t raw_data[length];
+	transfer(nullptr, 0, &raw_data[0], length);
+
+	uint8_t crc_err = 0;
+
+	for (int i = 0; i < length / 3; ++i) {
+		uint8_t crc_data[2] = {raw_data[i * 3], raw_data[i * 3 + 1]};
+
+		if (raw_data[i * 3 + 2] != calc_crc(crc_data)) {
+			crc_err ++;
+		}
+
+		*(data_ptr + i * 2) = raw_data[i * 3];
+		*(data_ptr + i * 2 + 1) = raw_data[i * 3 + 1];
+	}
+
+	return crc_err;
+}
+
+int SHT3X::write_data(uint16_t command, uint8_t buffer[], uint8_t length)
+{
+	_last_command = command;
+
+	uint8_t cmd[2 + 3 * length / 2];
+	cmd[0] = static_cast<uint8_t>(command >> 8);
+	cmd[1] = static_cast<uint8_t>(command & 0xff);
+
+	for (int i = 0; i < length / 2; ++i) {
+		cmd[2 + 3 * i] = buffer[2 * i];
+		cmd[2 + 3 * i + 1] = buffer[2 * i + 1];
+		uint8_t crc_data[2] = {buffer[2 * i], buffer[2 * i + 1]};
+		cmd[2 + 3 * i + 2] = calc_crc(crc_data);
+	}
+
+	return transfer(&cmd[0], sizeof(cmd), nullptr, 0);
+}
+
+
+void SHT3X::sensor_compouse_msg(bool send)
+{
+	uint8_t data[4];
+	int error = read_data(SHT3x_CMD_FETCH_DATA, &data[0], 6);
+
+	if (error == PX4_OK) {
+		measurement_time = hrt_absolute_time();
+		measurement_index ++;
+
+		measured_temperature = (float) 175 * (data[0] << 8 | data[1]) / 65535 - 45;
+		measured_humidity = (float) 100 * (data[2] << 8 | data[3]) / 65535;
+
+		if (send) {
+			sensor_hygrometer_s msg{};
+			msg.timestamp = hrt_absolute_time();
+			msg.timestamp_sample = measurement_time;
+			msg.temperature = measured_temperature;
+			msg.humidity = measured_humidity;
+			msg.device_id = _sht_info.serial_number;
+			_sensor_hygrometer_pub.publish(msg);
+		}
+	}
+}
+
+
+int
+SHT3X::probe()
+{
+	uint8_t type[2];
+	uint8_t nvalid;
+
+	nvalid = read_data(SHT3X_CMD_READ_STATUS, &type[0], 3);
+	return (!(nvalid == PX4_OK));
+	// 0 means I can see sensor
+}
+
+int SHT3X::init()
+{
+	if (I2C::init() != PX4_OK) {
+		return PX4_ERROR;
+	}
+
+	_sensor_hygrometer_pub.advertise();
+	ScheduleOnInterval(50000);
+	return PX4_OK;
+}
+
+
+
+int SHT3X::init_sensor()
+{
+	set_pointer(SHT3X_CMD_CLEAR_STATUS);
+	px4_usleep(2000);
+
+	// Get sensor serial number
+	uint8_t serial[4];
+	read_data(SHT3x_CMD_READ_SN, &serial[0], 6);
+
+	_sht_info.serial_number = ((uint32_t)serial[0] << 24
+				   | (uint32_t)serial[1] << 16
+				   | (uint32_t)serial[2] << 8
+				   | (uint32_t)serial[3]);
+
+	set_pointer(SHT3x_CMD_PERIODIC_2HZ_MEDIUM);
+	px4_usleep(2000);
+	probe();
+
+	PX4_INFO("Connected to SHT3x sensor, SN: %ld", _sht_info.serial_number);
+
+	return PX4_OK;
+}
+
+void SHT3X::RunImpl()
+{
+	switch (_state) {
+	case sht3x_state::INIT:
+		probe();
+		init_sensor();
+		_state = sht3x_state::MEASUREMENT;
+		break;
+
+	case sht3x_state::MEASUREMENT:
+		if ((hrt_absolute_time() - measurement_time) > 200000) {
+			sensor_compouse_msg(1);
+		}
+
+		if ((hrt_absolute_time() - measurement_time) > 3000000) {
+			_state = sht3x_state::ERROR_READOUT;
+		}
+
+		break;
+
+	case sht3x_state::ERROR_GENERAL:
+	case sht3x_state::ERROR_READOUT: {
+			if (_last_state != _state) {
+				PX4_INFO("I cant get new data. The sensor may be disconnected.");
+			}
+
+			if (probe() == PX4_OK) {
+				_state = sht3x_state::INIT;
+			}
+		}
+		break;
+	}
+
+	if (_last_state != _state) {
+		_time_in_state = hrt_absolute_time();
+		_last_state = _state;
+	}
+}
+
+
+void
+SHT3X::custom_method(const BusCLIArguments &cli)
+{
+	switch (cli.custom1) {
+
+	case 1: {
+			PX4_INFO("Last measured values (%.3fs ago, #%d)", (double)(hrt_absolute_time() - measurement_time) / 1000000.0,
+				 measurement_index);
+			PX4_INFO("Temp: %.3f, Hum: %.3f", (double)measured_temperature, (double)measured_humidity);
+
+		}
+		break;
+
+	case 2: {
+			_state = sht3x_state::INIT;
+		}
+		break;
+	}
+}
+
+
+void SHT3X::print_status()
+{
+	PX4_INFO("SHT3X sensor");
+	I2CSPIDriverBase::print_status();
+	PX4_INFO("SN: %ld", _sht_info.serial_number);
+	PX4_INFO("Status: %s", sht_state_names[_state]);
+}
+
+
+void SHT3X::print_usage()
+{
+	PRINT_MODULE_DESCRIPTION(
+		R"DESCR_STR(
+### Description
+SHT3x Temperature and Humidity Sensor Driver by Senserion.
+
+### Examples
+CLI usage example:
+$ sht3x start -X
+  Start the sensor driver on the external bus
+
+$ sht3x status
+  Print driver status
+
+$ sht3x values
+  Print last measured values
+
+$ sht3x reset
+  Reinitialize senzor, reset flags
+
+)DESCR_STR");
+
+	PRINT_MODULE_USAGE_NAME("sht3x", "driver");
+
+	PRINT_MODULE_USAGE_COMMAND("start");
+	PRINT_MODULE_USAGE_PARAMS_I2C_SPI_DRIVER(true, false);
+	PRINT_MODULE_USAGE_PARAMS_I2C_ADDRESS(0x44);
+
+	PRINT_MODULE_USAGE_PARAMS_I2C_KEEP_RUNNING_FLAG();
+	PRINT_MODULE_USAGE_DEFAULT_COMMANDS();
+
+	PRINT_MODULE_USAGE_COMMAND_DESCR("values", "Print actual data");
+    PRINT_MODULE_USAGE_COMMAND_DESCR("reset", "Reinitialize sensor");
+
+}
+
+int sht3x_main(int argc, char *argv[])
+{
+	using ThisDriver = SHT3X;
+	BusCLIArguments cli{true, false};
+	cli.default_i2c_frequency = 400000;
+	cli.i2c_address = 0x44;
+	cli.support_keep_running = true;
+
+	const char *verb = cli.parseDefaultArguments(argc, argv);
+
+	if (!verb) {
+		ThisDriver::print_usage();
+		return -1;
+	}
+
+	BusInstanceIterator iterator(MODULE_NAME, cli, DRV_HYGRO_DEVTYPE_SHT3X);
+
+	if (!strcmp(verb, "start")) {
+		return ThisDriver::module_start(cli, iterator);
+	}
+
+	if (!strcmp(verb, "stop")) {
+		return ThisDriver::module_stop(iterator);
+	}
+
+	if (!strcmp(verb, "status")) {
+		return ThisDriver::module_status(iterator);
+	}
+
+	if (!strcmp(verb, "values")) {
+		cli.custom1 = 1;
+		return ThisDriver::module_custom_method(cli, iterator, false);
+	}
+
+	if (!strcmp(verb, "reset")) {
+		cli.custom1 = 2;
+		return ThisDriver::module_custom_method(cli, iterator, false);
+	}
+
+	ThisDriver::print_usage();
+	return -1;
+}

src/drivers/hygrometer/sht3x/sht3x.h

@@ -0,0 +1,122 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 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 sht3x.h
+ *
+ * Header file for SHT3x driver
+ *
+ * @author Roman Dvorak <dvorakroman@thunderfly.cz>
+ *
+ */
+
+#pragma once
+
+#include <drivers/device/i2c.h>
+#include <drivers/drv_hrt.h>
+#include <mathlib/mathlib.h>
+#include <px4_platform_common/module.h>
+#include <px4_platform_common/module_params.h>
+#include <px4_platform_common/i2c_spi_buses.h>
+#include <uORB/Publication.hpp>
+#include <uORB/topics/sensor_hygrometer.h>
+
+#define SHT3X_CMD_READ_STATUS			0xF32D
+#define SHT3X_CMD_CLEAR_STATUS			0x3041
+#define SHT3x_CMD_PERIODIC_2HZ_MEDIUM	0x2220
+#define SHT3x_CMD_FETCH_DATA			0xE000
+#define SHT3x_CMD_READ_SN				0x3780
+
+
+using namespace time_literals;
+
+extern "C" __EXPORT int sht3x_main(int argc, char *argv[]);
+
+enum sht3x_state {
+	ERROR_GENERAL,
+	ERROR_READOUT,
+	INIT,
+	MEASUREMENT
+};
+const char *sht_state_names[] = {"General error", "Readout error", "Initialization",
+				 "Measurement"
+				};
+
+
+struct sht_info {
+	uint32_t serial_number;
+};
+
+
+class SHT3X : public device::I2C, public ModuleParams, public I2CSPIDriver<SHT3X>
+{
+public:
+	SHT3X(const I2CSPIDriverConfig &config);
+	~SHT3X() = default;
+
+	static void print_usage();
+	void RunImpl();
+
+	int    init() override;
+	int    probe() override;
+	int    init_sensor();
+	void   print_status() override;
+
+	void custom_method(const BusCLIArguments &cli);
+
+	int set_pointer(uint16_t command);
+	int read_data(uint16_t command, uint8_t *data_ptr, uint8_t length);
+	int write_data(uint16_t command, uint8_t buffer[], uint8_t length);
+
+	void sensor_compouse_msg(bool send);
+
+	uint8_t calc_crc(uint8_t data[2]);
+
+private:
+
+	float measured_temperature = 0;
+	float measured_humidity = 0;
+	uint32_t measurement_time = 0;
+	uint16_t measurement_index = 0;
+
+	sht_info _sht_info;
+	int _state = sht3x_state::INIT;
+	int _last_state = sht3x_state::INIT;
+	uint32_t _time_in_state = hrt_absolute_time();
+	uint16_t _last_command = 0;
+	uORB::Publication<sensor_hygrometer_s> _sensor_hygrometer_pub{ORB_ID(sensor_hygrometer)};
+
+	DEFINE_PARAMETERS(
+		(ParamInt<px4::params::SENS_EN_SHT3X>) _param_sens_en_sht3x
+	)
+};

src/drivers/hygrometer/sht3x/sht3x_params.c

@@ -0,0 +1,41 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 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.
+ *
+ ****************************************************************************/
+
+/**
+ * SHT3x temperature and hygrometer
+ *
+ * @reboot_required true
+ * @group Sensors
+ * @boolean
+  */
+PARAM_DEFINE_INT32(SENS_EN_SHT3X, 0);

src/modules/logger/logged_topics.cpp

@@ -87,6 +87,7 @@ void LoggedTopics::add_default_topics()
 	add_topic("rtl_time_estimate", 1000);
 	add_topic("safety");
 	add_topic("sensor_combined");
+	add_topic("sensor_hygrometer", 500);
 	add_optional_topic("sensor_correction");
 	add_optional_topic("sensor_gyro_fft", 50);
 	add_topic("sensor_selection");