Simplify lpf filter code

Begin with zero instead of the initializing value, as the latter doesn't make much sense in practice, but complicates the code much.
Various minor fixes
2026-03-30 03:54:20 +00:00 · 2026-01-24 09:43:46 +03:00 · 2026-01-24 09:34:16 +03:00 · 2026-01-24 09:32:49 +03:00 · 2026-01-24 09:31:32 +03:00 · 2026-01-23 02:41:43 +03:00
23 changed files with 257 additions and 199 deletions
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,8 +25,6 @@ jobs:
        path: flix/build
    - name: Build firmware for ESP32-S3
      run: make BOARD=esp32:esp32:esp32s3
-    - name: Build firmware with WiFi disabled
-      run: sed -i 's/^#define WIFI_ENABLED 1$/#define WIFI_ENABLED 0/' flix/flix.ino && make
    - name: Check c_cpp_properties.json
      run: tools/check_c_cpp_properties.py

--- a/.markdownlint.json
+++ b/.markdownlint.json
@@ -7,6 +7,7 @@
 	"MD024": false,
 	"MD033": false,
 	"MD034": false,
+	"MD040": false,
 	"MD059": false,
 	"MD044": {
 		"html_elements": false,
--- a/.vscode/c_cpp_properties.json
+++ b/.vscode/c_cpp_properties.json
@@ -6,19 +6,18 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/**",
-				"~/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/.arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Arduino/libraries/**",
 				"/usr/include/gazebo-11/",
 				"/usr/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -31,9 +30,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -53,19 +53,18 @@
 			"name": "Mac",
 			"includePath": [
 				"${workspaceFolder}/flix",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/include/**",
-				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/Library/Arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Documents/Arduino/libraries/**",
 				"/opt/homebrew/include/gazebo-11/",
 				"/opt/homebrew/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/flix.ino",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
@@ -78,9 +77,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -103,17 +103,16 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/**",
-				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Documents/Arduino/libraries/**"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -126,9 +125,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++.exe",
+			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++.exe",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
--- a/4
+++ b/4
@@ -13,10 +13,10 @@ monitor:

 dependencies .dependencies:
 	arduino-cli core update-index --config-file arduino-cli.yaml
-	arduino-cli core install esp32:esp32@3.2.0 --config-file arduino-cli.yaml
+	arduino-cli core install esp32:esp32@3.3.6 --config-file arduino-cli.yaml
 	arduino-cli lib update-index
 	arduino-cli lib install "FlixPeriph"
-	arduino-cli lib install "MAVLink"@2.0.16
+	arduino-cli lib install "MAVLink"@2.0.25
 	touch .dependencies

 gazebo/build cmake: gazebo/CMakeLists.txt
--- a/README.md
+++ b/README.md
@@ -21,15 +21,13 @@
 * Dedicated for education and research.
 * Made from general-purpose components.
 * Simple and clean source code in Arduino (<2k lines firmware).
+* Connectivity using Wi-Fi and MAVLink protocol.
 * Control using USB gamepad, remote control or smartphone.
-* Wi-Fi and MAVLink support.
 * Wireless command line interface and analyzing.
 * Precise simulation with Gazebo.
-* Python library.
+* Python library for scripting and automatic flights.
 * Textbook on flight control theory and practice ([in development](https://quadcopter.dev)).
-* *Position control (using external camera) and autonomous flights¹*.
-
-*¹ — planned.*
+* *Position control (planned)*.

 ## It actually flies

--- a/docs/book/gyro.md
+++ b/docs/book/gyro.md
@@ -87,13 +87,13 @@ Flix поддерживает следующие модели IMU:
 #include <FlixPeriph.h>
 #include <SPI.h>

-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);

 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 }
 ```
@@ -108,21 +108,21 @@ void setup() {
 #include <FlixPeriph.h>
 #include <SPI.h>

-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);

 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 }

 void loop() {
-	IMU.waitForData();
+	imu.waitForData();

 	float gx, gy, gz;
-	IMU.getGyro(gx, gy, gz);
+	imu.getGyro(gx, gy, gz);

 	Serial.printf("gx:%f gy:%f gz:%f\n", gx, gy, gz);
 	delay(50); // замедление вывода
@@ -135,36 +135,36 @@ void loop() {

 ## Конфигурация гироскопа

-В коде Flix настройка IMU происходит в функции `configureIMU`. В этой функции настраиваются три основных параметра гироскопа: диапазон измерений, частота сэмплов и частота LPF-фильтра.
+В коде Flix настройка IMU происходит в функции `configureIMU`. В этой функции настраиваются три основных параметра гироскопа: диапазон измерений, частота сэмплирования и частота LPF-фильтра.

-### Частота сэмплов
+### Частота сэмплирования

-Большинство IMU могут обновлять данные с разной частотой. В полетных контроллерах обычно используется частота обновления от 500 Гц до 8 кГц. Чем выше частота сэмплов, тем выше точность управления полетом, но и больше нагрузка на микроконтроллер.
+Большинство IMU могут обновлять данные с разной частотой. В полетных контроллерах обычно используется частота обновления от 500 Гц до 8 кГц. Чем выше частота, тем выше точность управления полетом, но и тем больше нагрузка на микроконтроллер.

-Частота сэмплов устанавливается методом `setSampleRate()`. В Flix используется частота 1 кГц:
+Частота сэмплирования устанавливается методом `setSampleRate()`. В Flix используется частота 1 кГц:

 ```cpp
 IMU.setRate(IMU.RATE_1KHZ_APPROX);
 ```

-Поскольку не все поддерживаемые IMU могут работать строго на частоте 1 кГц, в библиотеке FlixPeriph существует возможность приближенной настройки частоты сэмплов. Например, у IMU ICM-20948 при такой настройке реальная частота сэмплирования будет равна 1125 Гц.
+Поскольку не все поддерживаемые IMU могут работать строго на частоте 1 кГц, в библиотеке FlixPeriph существует возможность приближенной настройки частоты сэмплирования. Например, у IMU ICM-20948 при такой настройке реальная частота сэмплирования будет равна 1125 Гц.

 Другие доступные для установки в библиотеке FlixPeriph частоты сэмплирования:

-* `RATE_MIN` — минимальная частота сэмплов для конкретного IMU.
+* `RATE_MIN` — минимальная частота для конкретного IMU.
 * `RATE_50HZ_APPROX` — значение, близкое к 50 Гц.
 * `RATE_1KHZ_APPROX` — значение, близкое к 1 кГц.
 * `RATE_8KHZ_APPROX` — значение, близкое к 8 кГц.
-* `RATE_MAX` — максимальная частота сэмплов для конкретного IMU.
+* `RATE_MAX` — максимальная частота для конкретного IMU.

 #### Диапазон измерений

-Большинство MEMS-гироскопов поддерживают несколько диапазонов измерений угловой скорости. Главное преимущество выбора меньшего диапазона — бо́льшая чувствительность. В полетных контроллерах обычно выбирается максимальный диапазон измерений от –2000 до 2000 градусов в секунду, чтобы обеспечить возможность динамичных маневров.
+Большинство MEMS-гироскопов поддерживают несколько диапазонов измерений угловой скорости. Главное преимущество выбора меньшего диапазона — бо́льшая чувствительность. В полетных контроллерах обычно выбирается максимальный диапазон измерений от –2000 до 2000 градусов в секунду, чтобы обеспечить возможность быстрых маневров.

 В библиотеке FlixPeriph диапазон измерений гироскопа устанавливается методом `setGyroRange()`:

 ```cpp
-IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
+imu.setGyroRange(imu.GYRO_RANGE_2000DPS);
 ```

 ### LPF-фильтр
@@ -172,7 +172,7 @@ IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
 IMU InvenSense могут фильтровать измерения на аппаратном уровне при помощи фильтра нижних частот (LPF). Flix реализует собственный фильтр для гироскопа, чтобы иметь больше гибкости при поддержке разных IMU. Поэтому для встроенного LPF устанавливается максимальная частота среза:

 ```cpp
-IMU.setDLPF(IMU.DLPF_MAX);
+imu.setDLPF(imu.DLPF_MAX);
 ```

 ## Калибровка гироскопа
@@ -181,7 +181,7 @@ IMU.setDLPF(IMU.DLPF_MAX);

 \\[ gyro_{xyz}=rates_{xyz}+bias_{xyz}+noise \\]

-Для качественной работы подсистемы оценки ориентации и управления дроном необходимо оценить *bias* гироскопа и учесть его в вычислениях. Для этого при запуске программы производится калибровка гироскопа, которая реализована в функции `calibrateGyro()`. Эта функция считывает данные с гироскопа в состоянии покоя 1000 раз и усредняет их. Полученные значения считаются *bias* гироскопа и в дальнейшем вычитаются из измерений.
+Для точной работы подсистемы оценки ориентации и управления дроном необходимо оценить *bias* гироскопа и учесть его в вычислениях. Для этого при запуске программы производится калибровка гироскопа, которая реализована в функции `calibrateGyro()`. Эта функция считывает данные с гироскопа в состоянии покоя 1000 раз и усредняет их. Полученные значения считаются *bias* гироскопа и в дальнейшем вычитаются из измерений.

 Программа для вывода данных с гироскопа с калибровкой:

@@ -189,23 +189,23 @@ IMU.setDLPF(IMU.DLPF_MAX);
 #include <FlixPeriph.h>
 #include <SPI.h>

-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);

 float gyroBiasX, gyroBiasY, gyroBiasZ; // bias гироскопа

 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 	calibrateGyro();
 }

 void loop() {
 	float gx, gy, gz;
-	IMU.waitForData();
-	IMU.getGyro(gx, gy, gz);
+	imu.waitForData();
+	imu.getGyro(gx, gy, gz);

 	// Устранение bias гироскопа
 	gx -= gyroBiasX;
@@ -226,9 +226,9 @@ void calibrateGyro() {

 	// Получение 1000 измерений гироскопа
 	for (int i = 0; i < samples; i++) {
-		IMU.waitForData();
+		imu.waitForData();
 		float gx, gy, gz;
-		IMU.getGyro(gx, gy, gz);
+		imu.getGyro(gx, gy, gz);
 		gyroBiasX += gx;
 		gyroBiasY += gy;
 		gyroBiasZ += gz;
--- a/docs/firmware.md
+++ b/docs/firmware.md
@@ -42,7 +42,7 @@ Pilot inputs are interpreted in `interpretControls()`, and then converted to the

 * `attitudeTarget` *(Quaternion)* — target attitude of the drone.
 * `ratesTarget` *(Vector)* — target angular rates, *rad/s*.
-* `ratesExtra` *(Vector)* — additional (feed-forward) angular rates , used for yaw rate control in STAB mode, *rad/s*.
+* `ratesExtra` *(Vector)* — additional (feed-forward) angular rates, used for yaw rate control in STAB mode, *rad/s*.
 * `torqueTarget` *(Vector)* — target torque, range [-1, 1].
 * `thrustTarget` *(float)* — collective motor thrust target, range [0, 1].

--- a/docs/img/flix.svg
+++ b/docs/img/flix.svg
@@ -1,4 +1,4 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 718.86 362.46">
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 734.86 378.46">
  <defs>
    <style>
      .a {
@@ -23,16 +23,16 @@
  </defs>
  <g>
    <g>
-      <line class="a" x1="443.12" y1="283.88" x2="641.43" y2="84.58"/>
-      <line class="a" x1="444.12" y1="85.58" x2="642.42" y2="284.87"/>
-      <circle class="b" cx="542.77" cy="184.23" r="41.15"/>
-      <circle class="c" cx="443.69" cy="85.08" r="77.29"/>
-      <circle class="c" cx="641.55" cy="84.87" r="77.29"/>
-      <circle class="c" cx="640.56" cy="284.16" r="77.29"/>
-      <circle class="c" cx="443.25" cy="284.16" r="77.29"/>
+      <line class="a" x1="448.78" y1="294.23" x2="648.77" y2="93.24"/>
+      <line class="a" x1="449.78" y1="94.24" x2="649.77" y2="295.23"/>
+      <circle class="b" cx="549.27" cy="193.73" r="41.5"/>
+      <circle class="c" cx="449.35" cy="93.74" r="77.95"/>
+      <circle class="c" cx="648.89" cy="93.53" r="77.95"/>
+      <circle class="c" cx="647.89" cy="294.51" r="77.95"/>
+      <circle class="c" cx="448.9" cy="294.51" r="77.95"/>
    </g>
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  </g>
 </svg>
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -16,7 +16,7 @@ Do the following:
 * **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button to make sure you see the whole ESP32 output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
 * **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
-* **Check if the CLI is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the CLI using QGroundControl (*Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*).
+* **Check if the console is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the console using QGroundControl (*Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*).
 * **Configure QGroundControl correctly before connecting to the drone** if you use it to control the drone. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 * **If QGroundControl doesn't connect**, you might need to disable the firewall and/or VPN on your computer.
 * **Check the IMU is working**. Perform `imu` command and check its output:
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -20,10 +20,10 @@ You can build and upload the firmware using either **Arduino IDE** (easier for b

 1. Install [Arduino IDE](https://www.arduino.cc/en/software) (version 2 is recommended).
 2. *Windows users might need to install [USB to UART bridge driver from Silicon Labs](https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers).*
-3. Install ESP32 core, version 3.2.0. See the [official Espressif's instructions](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html#installing-using-arduino-ide) on installing ESP32 Core in Arduino IDE.
+3. Install ESP32 core, version 3.3.6. See the [official Espressif's instructions](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html#installing-using-arduino-ide) on installing ESP32 Core in Arduino IDE.
 4. Install the following libraries using [Library Manager](https://docs.arduino.cc/software/ide-v2/tutorials/ide-v2-installing-a-library):
   * `FlixPeriph`, the latest version.
-   * `MAVLink`, version 2.0.16.
+   * `MAVLink`, version 2.0.25.
 5. Open the `flix/flix.ino` sketch from downloaded firmware sources in Arduino IDE.
 6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini) and the port.
 7. [Build and upload](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-uploading-a-sketch) the firmware using Arduino IDE.
@@ -108,7 +108,7 @@ The drone is configured using parameters. To access and modify them, go to the Q

 <img src="img/parameters.png" width="400">

-You can also work with parameters using `p` command in the console.
+You can also work with parameters using `p` command in the console. Parameter names are case-insensitive.

 ### Define IMU orientation

@@ -143,9 +143,9 @@ Before flight you need to calibrate the accelerometer:
   * The `accel` and `gyro` fields should change as you move the drone.
   * The `landed` field should be `1` when the drone is still on the ground and `0` when you lift it up.

-2. Check the attitude estimation: connect to the drone using QGroundControl, rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct. Attitude indicator in QGroundControl is shown below:
+2. Check the attitude estimation: connect to the drone using QGroundControl, rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct. Compare your attitude indicator (in the *large vertical* mode) to the video:

-   <img src="img/qgc-attitude.png" height="200">
+    <a href="https://youtu.be/yVRN23-GISU"><img width=300 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>

 3. Perform motor tests in the console. Use the following commands **— remove the propellers before running the tests!**

@@ -243,9 +243,43 @@ In this mode, the pilot inputs are ignored (except the mode switch, if configure

 If the pilot moves the control sticks, the drone will switch back to *STAB* mode.

+## Wi-Fi configuration
+
+You can configure the Wi-Fi using parameters and console commands.
+
+The Wi-Fi mode is chosen using `WIFI_MODE` parameter in QGroundControl or in the console:
+
+* `0` — Wi-Fi is disabled.
+* `1` — Access Point mode (*AP*) — the drone creates a Wi-Fi network.
+* `2` — Client mode (*STA*) — the drone connects to an existing Wi-Fi network.
+* `3` — *ESP-NOW (not implemented yet)*.
+
+> [!WARNING]
+> Tests showed that Client mode may cause **additional delays** in remote control (due to retranslations), so it's generally not recommended.
+
+The SSID and password are configured using the `ap` and `sta` console commands:
+
+```
+ap <ssid> <password>
+sta <ssid> <password>
+```
+
+Example of configuring the Access Point mode:
+
+```
+ap my-flix-ssid mypassword123
+p WIFI_MODE 1
+```
+
+Disabling Wi-Fi:
+
+```
+p WIFI_MODE 0
+```
+
 ## Flight log

-After the flight, you can download the flight log for analysis wirelessly. Use the following for that:
+After the flight, you can download the flight log for analysis wirelessly. Use the following command on your computer for that:

 ```bash
 make log
--- a/flix/cli.ino
+++ b/flix/cli.ino
@@ -6,6 +6,7 @@
 #include "pid.h"
 #include "vector.h"
 #include "util.h"
+#include "lpf.h"

 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern const int RAW, ACRO, STAB, AUTO;
@@ -14,6 +15,7 @@ extern uint16_t channels[16];
 extern float controlTime;
 extern int mode;
 extern bool armed;
+extern LowPassFilter<Vector> gyroBiasFilter;

 const char* motd =
 "\nWelcome to\n"
@@ -38,6 +40,8 @@ const char* motd =
 "raw/stab/acro/auto - set mode\n"
 "rc - show RC data\n"
 "wifi - show Wi-Fi info\n"
+"ap <ssid> <password> - setup Wi-Fi access point\n"
+"sta <ssid> <password> - setup Wi-Fi client mode\n"
 "mot - show motor output\n"
 "log [dump] - print log header [and data]\n"
 "cr - calibrate RC\n"
@@ -54,9 +58,7 @@ void print(const char* format, ...) {
 	vsnprintf(buf, sizeof(buf), format, args);
 	va_end(args);
 	Serial.print(buf);
-#if WIFI_ENABLED
 	mavlinkPrint(buf);
-#endif
 }

 void pause(float duration) {
@@ -64,9 +66,7 @@ void pause(float duration) {
 	while (t - start < duration) {
 		step();
 		handleInput();
-#if WIFI_ENABLED
 		processMavlink();
-#endif
 		delay(50);
 	}
 }
@@ -136,9 +136,11 @@ void doCommand(String str, bool echo = false) {
 		print("mode: %s\n", getModeName());
 		print("armed: %d\n", armed);
 	} else if (command == "wifi") {
-#if WIFI_ENABLED
 		printWiFiInfo();
-#endif
+	} else if (command == "ap") {
+		configWiFi(true, arg0.c_str(), arg1.c_str());
+	} else if (command == "sta") {
+		configWiFi(false, arg0.c_str(), arg1.c_str());
 	} else if (command == "mot") {
 		print("front-right %g front-left %g rear-right %g rear-left %g\n",
 			motors[MOTOR_FRONT_RIGHT], motors[MOTOR_FRONT_LEFT], motors[MOTOR_REAR_RIGHT], motors[MOTOR_REAR_LEFT]);
@@ -178,6 +180,7 @@ void doCommand(String str, bool echo = false) {
 #endif
 	} else if (command == "reset") {
 		attitude = Quaternion();
+		gyroBiasFilter.reset();
 	} else if (command == "reboot") {
 		ESP.restart();
 	} else {
--- a/flix/control.ino
+++ b/flix/control.ino
@@ -38,6 +38,12 @@ const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3; // flight modes
 int mode = STAB;
 bool armed = false;

+Quaternion attitudeTarget;
+Vector ratesTarget;
+Vector ratesExtra; // feedforward rates
+Vector torqueTarget;
+float thrustTarget;
+
 PID rollRatePID(ROLLRATE_P, ROLLRATE_I, ROLLRATE_D, ROLLRATE_I_LIM, RATES_D_LPF_ALPHA);
 PID pitchRatePID(PITCHRATE_P, PITCHRATE_I, PITCHRATE_D, PITCHRATE_I_LIM, RATES_D_LPF_ALPHA);
 PID yawRatePID(YAWRATE_P, YAWRATE_I, YAWRATE_D);
@@ -47,12 +53,6 @@ PID yawPID(YAW_P, 0, 0);
 Vector maxRate(ROLLRATE_MAX, PITCHRATE_MAX, YAWRATE_MAX);
 float tiltMax = TILT_MAX;

-Quaternion attitudeTarget;
-Vector ratesTarget;
-Vector ratesExtra; // feedforward rates
-Vector torqueTarget;
-float thrustTarget;
-
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;

--- a/flix/flix.ino
+++ b/flix/flix.ino
@@ -7,8 +7,6 @@
 #include "quaternion.h"
 #include "util.h"

-#define WIFI_ENABLED 1
-
 extern float t, dt;
 extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
 extern Vector gyro, acc;
@@ -25,9 +23,7 @@ void setup() {
 	setupLED();
 	setupMotors();
 	setLED(true);
-#if WIFI_ENABLED
 	setupWiFi();
-#endif
 	setupIMU();
 	setupRC();
 	setLED(false);
@@ -42,9 +38,7 @@ void loop() {
 	control();
 	sendMotors();
 	handleInput();
-#if WIFI_ENABLED
 	processMavlink();
-#endif
 	logData();
 	syncParameters();
 }
--- a/flix/imu.ino
+++ b/flix/imu.ino
@@ -19,6 +19,8 @@ Vector acc; // accelerometer output, m/s/s
 Vector accBias;
 Vector accScale(1, 1, 1);

+LowPassFilter<Vector> gyroBiasFilter(0.001);
+
 void setupIMU() {
 	print("Setup IMU\n");
 	imu.begin();
@@ -50,8 +52,6 @@ void readIMU() {
 void calibrateGyroOnce() {
 	static Delay landedDelay(2);
 	if (!landedDelay.update(landed)) return; // calibrate only if definitely stationary
-
-	static LowPassFilter<Vector> gyroBiasFilter(0.001);
 	gyroBias = gyroBiasFilter.update(gyro);
 }

--- a/flix/lpf.h
+++ b/flix/lpf.h
@@ -14,15 +14,6 @@ public:
 	LowPassFilter(float alpha): alpha(alpha) {};

 	T update(const T input) {
-		if (alpha == 1) { // filter disabled
-			return input;
-		}
-
-		if (!initialized) {
-			output = input;
-			initialized = true;
-		}
-
 		return output += alpha * (input - output);
 	}

@@ -31,9 +22,6 @@ public:
 	}

 	void reset() {
-		initialized = false;
+		output = T(); // set to zero
 	}
-
-private:
-	bool initialized = false;
 };
--- a/flix/mavlink.ino
+++ b/flix/mavlink.ino
@@ -3,19 +3,16 @@

 // MAVLink communication

-#if WIFI_ENABLED
-
 #include <MAVLink.h>
 #include "util.h"

-#define SYSTEM_ID 1
-#define MAVLINK_RATE_SLOW 1
-#define MAVLINK_RATE_FAST 10
-
 extern float controlTime;

 bool mavlinkConnected = false;
 String mavlinkPrintBuffer;
+int mavlinkSysId = 1;
+Rate telemetryFast(10);
+Rate telemetrySlow(2);

 void processMavlink() {
 	sendMavlink();
@@ -28,10 +25,8 @@ void sendMavlink() {
 	mavlink_message_t msg;
 	uint32_t time = t * 1000;

-	static Rate slow(MAVLINK_RATE_SLOW), fast(MAVLINK_RATE_FAST);
-
-	if (slow) {
-		mavlink_msg_heartbeat_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC,
+	if (telemetrySlow) {
+		mavlink_msg_heartbeat_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC,
 			(armed ? MAV_MODE_FLAG_SAFETY_ARMED : 0) |
 			((mode == STAB) ? MAV_MODE_FLAG_STABILIZE_ENABLED : 0) |
 			((mode == AUTO) ? MAV_MODE_FLAG_AUTO_ENABLED : MAV_MODE_FLAG_MANUAL_INPUT_ENABLED),
@@ -40,27 +35,27 @@ void sendMavlink() {

 		if (!mavlinkConnected) return; // send only heartbeat until connected

-		mavlink_msg_extended_sys_state_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_extended_sys_state_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			MAV_VTOL_STATE_UNDEFINED, landed ? MAV_LANDED_STATE_ON_GROUND : MAV_LANDED_STATE_IN_AIR);
 		sendMessage(&msg);
 	}

-	if (fast && mavlinkConnected) {
+	if (telemetryFast && mavlinkConnected) {
 		const float zeroQuat[] = {0, 0, 0, 0};
-		mavlink_msg_attitude_quaternion_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_attitude_quaternion_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			time, attitude.w, attitude.x, -attitude.y, -attitude.z, rates.x, -rates.y, -rates.z, zeroQuat); // convert to frd
 		sendMessage(&msg);

-		mavlink_msg_rc_channels_raw_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, controlTime * 1000, 0,
+		mavlink_msg_rc_channels_raw_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, controlTime * 1000, 0,
 			channels[0], channels[1], channels[2], channels[3], channels[4], channels[5], channels[6], channels[7], UINT8_MAX);
 		if (channels[0] != 0) sendMessage(&msg); // 0 means no RC input

 		float controls[8];
 		memcpy(controls, motors, sizeof(motors));
-		mavlink_msg_actuator_control_target_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0, controls);
+		mavlink_msg_actuator_control_target_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0, controls);
 		sendMessage(&msg);

-		mavlink_msg_scaled_imu_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time,
+		mavlink_msg_scaled_imu_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time,
 			acc.x * 1000, -acc.y * 1000, -acc.z * 1000, // convert to frd
 			gyro.x * 1000, -gyro.y * 1000, -gyro.z * 1000,
 			0, 0, 0, 0);
@@ -95,7 +90,7 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_MANUAL_CONTROL) {
 		mavlink_manual_control_t m;
 		mavlink_msg_manual_control_decode(&msg, &m);
-		if (m.target && m.target != SYSTEM_ID) return; // 0 is broadcast
+		if (m.target && m.target != mavlinkSysId) return; // 0 is broadcast

 		controlThrottle = m.z / 1000.0f;
 		controlPitch = m.x / 1000.0f;
@@ -108,11 +103,11 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_REQUEST_LIST) {
 		mavlink_param_request_list_t m;
 		mavlink_msg_param_request_list_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		mavlink_message_t msg;
 		for (int i = 0; i < parametersCount(); i++) {
-			mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+			mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 				getParameterName(i), getParameter(i), MAV_PARAM_TYPE_REAL32, parametersCount(), i);
 			sendMessage(&msg);
 		}
@@ -121,7 +116,7 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_REQUEST_READ) {
 		mavlink_param_request_read_t m;
 		mavlink_msg_param_request_read_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		char name[MAVLINK_MSG_PARAM_REQUEST_READ_FIELD_PARAM_ID_LEN + 1];
 		strlcpy(name, m.param_id, sizeof(name)); // param_id might be not null-terminated
@@ -130,7 +125,7 @@ void handleMavlink(const void *_msg) {
 			memcpy(name, getParameterName(m.param_index), 16);
 		}
 		mavlink_message_t msg;
-		mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			name, value, MAV_PARAM_TYPE_REAL32, parametersCount(), m.param_index);
 		sendMessage(&msg);
 	}
@@ -138,32 +133,33 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_SET) {
 		mavlink_param_set_t m;
 		mavlink_msg_param_set_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		char name[MAVLINK_MSG_PARAM_SET_FIELD_PARAM_ID_LEN + 1];
 		strlcpy(name, m.param_id, sizeof(name)); // param_id might be not null-terminated
-		setParameter(name, m.param_value);
+		bool success = setParameter(name, m.param_value);
+		if (!success) return;
 		// send ack
 		mavlink_message_t msg;
-		mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
-			m.param_id, m.param_value, MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
+		mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
+			m.param_id, getParameter(name), MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
 		sendMessage(&msg);
 	}

 	if (msg.msgid == MAVLINK_MSG_ID_MISSION_REQUEST_LIST) { // handle to make qgc happy
 		mavlink_mission_request_list_t m;
 		mavlink_msg_mission_request_list_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		mavlink_message_t msg;
-		mavlink_msg_mission_count_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, 0, 0, 0, MAV_MISSION_TYPE_MISSION, 0);
+		mavlink_msg_mission_count_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, 0, 0, MAV_MISSION_TYPE_MISSION, 0);
 		sendMessage(&msg);
 	}

 	if (msg.msgid == MAVLINK_MSG_ID_SERIAL_CONTROL) {
 		mavlink_serial_control_t m;
 		mavlink_msg_serial_control_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		char data[MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN + 1];
 		strlcpy(data, (const char *)m.data, m.count); // data might be not null-terminated
@@ -175,7 +171,7 @@ void handleMavlink(const void *_msg) {

 		mavlink_set_attitude_target_t m;
 		mavlink_msg_set_attitude_target_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		// copy attitude, rates and thrust targets
 		ratesTarget.x = m.body_roll_rate;
@@ -197,7 +193,7 @@ void handleMavlink(const void *_msg) {

 		mavlink_set_actuator_control_target_t m;
 		mavlink_msg_set_actuator_control_target_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		attitudeTarget.invalidate();
 		ratesTarget.invalidate();
@@ -209,12 +205,12 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_LOG_REQUEST_DATA) {
 		mavlink_log_request_data_t m;
 		mavlink_msg_log_request_data_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;

 		// Send all log records
 		for (int i = 0; i < sizeof(logBuffer) / sizeof(logBuffer[0]); i++) {
 			mavlink_message_t msg;
-			mavlink_msg_log_data_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, 0, i,
+			mavlink_msg_log_data_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, i,
 				sizeof(logBuffer[0]), (uint8_t *)logBuffer[i]);
 			sendMessage(&msg);
 		}
@@ -224,13 +220,13 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_COMMAND_LONG) {
 		mavlink_command_long_t m;
 		mavlink_msg_command_long_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 		mavlink_message_t response;
 		bool accepted = false;

 		if (m.command == MAV_CMD_REQUEST_MESSAGE && m.param1 == MAVLINK_MSG_ID_AUTOPILOT_VERSION) {
 			accepted = true;
-			mavlink_msg_autopilot_version_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &response,
+			mavlink_msg_autopilot_version_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &response,
 				MAV_PROTOCOL_CAPABILITY_PARAM_FLOAT | MAV_PROTOCOL_CAPABILITY_MAVLINK2, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0);
 			sendMessage(&response);
 		}
@@ -249,7 +245,7 @@ void handleMavlink(const void *_msg) {

 		// send command ack
 		mavlink_message_t ack;
-		mavlink_msg_command_ack_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, accepted ? MAV_RESULT_ACCEPTED : MAV_RESULT_UNSUPPORTED, UINT8_MAX, 0, msg.sysid, msg.compid);
+		mavlink_msg_command_ack_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, accepted ? MAV_RESULT_ACCEPTED : MAV_RESULT_UNSUPPORTED, UINT8_MAX, 0, msg.sysid, msg.compid);
 		sendMessage(&ack);
 	}
 }
@@ -266,7 +262,7 @@ void sendMavlinkPrint() {
 		char data[MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN + 1];
 		strlcpy(data, str + i, sizeof(data));
 		mavlink_message_t msg;
-		mavlink_msg_serial_control_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_serial_control_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			SERIAL_CONTROL_DEV_SHELL,
 			i + MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN < strlen(str) ? SERIAL_CONTROL_FLAG_MULTI : 0, // more chunks to go
 			0, 0, strlen(data), (uint8_t *)data, 0, 0);
@@ -274,5 +270,3 @@ void sendMavlinkPrint() {
 	}
 	mavlinkPrintBuffer.clear();
 }
-
-#endif
--- a/flix/parameters.ino
+++ b/flix/parameters.ino
@@ -9,13 +9,20 @@
 extern float channelZero[16];
 extern float channelMax[16];
 extern float rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
+extern int wifiMode, udpLocalPort, udpRemotePort;
+extern float rcLossTimeout, descendTime;

 Preferences storage;

 struct Parameter {
 	const char *name; // max length is 15 (Preferences key limit)
-	float *variable;
-	float value; // cache
+	bool integer;
+	union { float *f; int *i; }; // pointer to variable
+	float cache; // what's stored in flash
+	Parameter(const char *name, float *variable) : name(name), integer(false), f(variable) {};
+	Parameter(const char *name, int *variable) : name(name), integer(true), i(variable) {};
+	float getValue() const { return integer ? *i : *f; };
+	void setValue(const float value) { if (integer) *i = value; else *f = value; };
 };

 Parameter parameters[] = {
@@ -52,6 +59,7 @@ Parameter parameters[] = {
 	{"IMU_ACC_SCALE_X", &accScale.x},
 	{"IMU_ACC_SCALE_Y", &accScale.y},
 	{"IMU_ACC_SCALE_Z", &accScale.z},
+	{"IMU_GYRO_BIAS_A", &gyroBiasFilter.alpha},
 	// estimate
 	{"EST_ACC_WEIGHT", &accWeight},
 	{"EST_RATES_LPF_A", &ratesFilter.alpha},
@@ -77,6 +85,17 @@ Parameter parameters[] = {
 	{"RC_THROTTLE", &throttleChannel},
 	{"RC_YAW", &yawChannel},
 	{"RC_MODE", &modeChannel},
+	// wifi
+	{"WIFI_MODE", &wifiMode},
+	{"WIFI_LOC_PORT", &udpLocalPort},
+	{"WIFI_REM_PORT", &udpRemotePort},
+	// mavlink
+	{"MAV_SYS_ID", &mavlinkSysId},
+	{"MAV_RATE_SLOW", &telemetrySlow.rate},
+	{"MAV_RATE_FAST", &telemetryFast.rate},
+	// safety
+	{"SF_RC_LOSS_TIME", &rcLossTimeout},
+	{"SF_DESCEND_TIME", &descendTime},
 };

 void setupParameters() {
@@ -84,10 +103,10 @@ void setupParameters() {
 	// Read parameters from storage
 	for (auto &parameter : parameters) {
 		if (!storage.isKey(parameter.name)) {
-			storage.putFloat(parameter.name, *parameter.variable);
+			storage.putFloat(parameter.name, parameter.getValue()); // store default value
 		}
-		*parameter.variable = storage.getFloat(parameter.name, *parameter.variable);
-		parameter.value = *parameter.variable;
+		parameter.setValue(storage.getFloat(parameter.name, 0));
+		parameter.cache = parameter.getValue();
 	}
 }

@@ -102,13 +121,13 @@ const char *getParameterName(int index) {

 float getParameter(int index) {
 	if (index < 0 || index >= parametersCount()) return NAN;
-	return *parameters[index].variable;
+	return parameters[index].getValue();
 }

 float getParameter(const char *name) {
 	for (auto &parameter : parameters) {
-		if (strcmp(parameter.name, name) == 0) {
-			return *parameter.variable;
+		if (strcasecmp(parameter.name, name) == 0) {
+			return parameter.getValue();
 		}
 	}
 	return NAN;
@@ -116,8 +135,9 @@ float getParameter(const char *name) {

 bool setParameter(const char *name, const float value) {
 	for (auto &parameter : parameters) {
-		if (strcmp(parameter.name, name) == 0) {
-			*parameter.variable = value;
+		if (strcasecmp(parameter.name, name) == 0) {
+			if (parameter.integer && !isfinite(value)) return false; // can't set integer to NaN or Inf
+			parameter.setValue(value);
 			return true;
 		}
 	}
@@ -130,16 +150,18 @@ void syncParameters() {
 	if (motorsActive()) return; // don't use flash while flying, it may cause a delay

 	for (auto &parameter : parameters) {
-		if (parameter.value == *parameter.variable) continue;
-		if (isnan(parameter.value) && isnan(*parameter.variable)) continue; // handle NAN != NAN
-		storage.putFloat(parameter.name, *parameter.variable);
-		parameter.value = *parameter.variable;
+		if (parameter.getValue() == parameter.cache) continue; // no change
+		if (isnan(parameter.getValue()) && isnan(parameter.cache)) continue; // both are NaN
+		if (isinf(parameter.getValue()) && isinf(parameter.cache)) continue; // both are Inf
+
+		storage.putFloat(parameter.name, parameter.getValue());
+		parameter.cache = parameter.getValue(); // update cache
 	}
 }

 void printParameters() {
 	for (auto &parameter : parameters) {
-		print("%s = %g\n", parameter.name, *parameter.variable);
+		print("%s = %g\n", parameter.name, parameter.getValue());
 	}
 }

--- a/flix/rc.ino
+++ b/flix/rc.ino
@@ -13,10 +13,10 @@ float channelZero[16]; // calibration zero values
 float channelMax[16]; // calibration max values

 float controlRoll, controlPitch, controlYaw, controlThrottle; // pilot's inputs, range [-1, 1]
-float controlMode = NAN; //
-float controlTime; // time of the last controls update (0 when no RC)
+float controlMode = NAN;
+float controlTime = NAN; // time of the last controls update

-// Channels mapping (using float to store in parameters):
+// Channels mapping (nan means not assigned):
 float rollChannel = NAN, pitchChannel = NAN, throttleChannel = NAN, yawChannel = NAN, modeChannel = NAN;

 void setupRC() {
--- a/flix/safety.ino
+++ b/flix/safety.ino
@@ -3,12 +3,12 @@

 // Fail-safe functions

-#define RC_LOSS_TIMEOUT 1
-#define DESCEND_TIME 10
-
 extern float controlTime;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw;

+float rcLossTimeout = 1;
+float descendTime = 10;
+
 void failsafe() {
 	rcLossFailsafe();
 	autoFailsafe();
@@ -16,9 +16,8 @@ void failsafe() {

 // RC loss failsafe
 void rcLossFailsafe() {
-	if (controlTime == 0) return; // no RC at all
 	if (!armed) return;
-	if (t - controlTime > RC_LOSS_TIMEOUT) {
+	if (t - controlTime > rcLossTimeout) {
 		descend();
 	}
 }
@@ -27,7 +26,7 @@ void rcLossFailsafe() {
 void descend() {
 	mode = AUTO;
 	attitudeTarget = Quaternion();
-	thrustTarget -= dt / DESCEND_TIME;
+	thrustTarget -= dt / descendTime;
 	if (thrustTarget < 0) {
 		thrustTarget = 0;
 		armed = false;
--- a/flix/wifi.ino
+++ b/flix/wifi.ino
@@ -1,49 +1,76 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix

-// Wi-Fi support
-
-#if WIFI_ENABLED
+// Wi-Fi communication

 #include <WiFi.h>
 #include <WiFiAP.h>
 #include <WiFiUdp.h>
+#include "Preferences.h"

-#define WIFI_SSID "flix"
-#define WIFI_PASSWORD "flixwifi"
-#define WIFI_UDP_PORT 14550
-#define WIFI_UDP_REMOTE_PORT 14550
-#define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
+extern Preferences storage; // use the main preferences storage
+
+const int W_DISABLED = 0, W_AP = 1, W_STA = 2;
+int wifiMode = W_AP;
+int udpLocalPort = 14550;
+int udpRemotePort = 14550;
+IPAddress udpRemoteIP = "255.255.255.255";

 WiFiUDP udp;

 void setupWiFi() {
 	print("Setup Wi-Fi\n");
-	WiFi.softAP(WIFI_SSID, WIFI_PASSWORD);
-	udp.begin(WIFI_UDP_PORT);
+	if (wifiMode == W_AP) {
+		WiFi.softAP(storage.getString("WIFI_AP_SSID", "flix").c_str(), storage.getString("WIFI_AP_PASS", "flixwifi").c_str());
+	} else if (wifiMode == W_STA) {
+		WiFi.begin(storage.getString("WIFI_STA_SSID", "").c_str(), storage.getString("WIFI_STA_PASS", "").c_str());
+	}
+	udp.begin(udpLocalPort);
 }

 void sendWiFi(const uint8_t *buf, int len) {
-	if (WiFi.softAPIP() == IPAddress(0, 0, 0, 0) && WiFi.status() != WL_CONNECTED) return;
-	udp.beginPacket(udp.remoteIP() ? udp.remoteIP() : WIFI_UDP_REMOTE_ADDR, WIFI_UDP_REMOTE_PORT);
+	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
+	udp.beginPacket(udpRemoteIP, udpRemotePort);
 	udp.write(buf, len);
 	udp.endPacket();
 }

 int receiveWiFi(uint8_t *buf, int len) {
 	udp.parsePacket();
+	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
 	return udp.read(buf, len);
 }

 void printWiFiInfo() {
+	if (WiFi.getMode() == WIFI_MODE_AP) {
+		print("Mode: Access Point (AP)\n");
 		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
 		print("SSID: %s\n", WiFi.softAPSSID().c_str());
-	print("Password: %s\n", WIFI_PASSWORD);
+		print("Password: ***\n");
 		print("Clients: %d\n", WiFi.softAPgetStationNum());
-	print("Status: %d\n", WiFi.status());
 		print("IP: %s\n", WiFi.softAPIP().toString().c_str());
-	print("Remote IP: %s\n", udp.remoteIP().toString().c_str());
+	} else if (WiFi.getMode() == WIFI_MODE_STA) {
+		print("Mode: Client (STA)\n");
+		print("Connected: %d\n", WiFi.isConnected());
+		print("MAC: %s\n", WiFi.macAddress().c_str());
+		print("SSID: %s\n", WiFi.SSID().c_str());
+		print("Password: ***\n");
+		print("IP: %s\n", WiFi.localIP().toString().c_str());
+	} else {
+		print("Mode: Disabled\n");
+		return;
+	}
+	print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
 	print("MAVLink connected: %d\n", mavlinkConnected);
 }

-#endif
+void configWiFi(bool ap, const char *ssid, const char *password) {
+	if (ap) {
+		storage.putString("WIFI_AP_SSID", ssid);
+		storage.putString("WIFI_AP_PASS", password);
+	} else {
+		storage.putString("WIFI_STA_SSID", ssid);
+		storage.putString("WIFI_STA_PASS", password);
+	}
+	print("✓ Reboot to apply new settings\n");
+}
--- a/gazebo/flix.h
+++ b/gazebo/flix.h
@@ -10,8 +10,6 @@
 #include "Arduino.h"
 #include "wifi.h"

-#define WIFI_ENABLED 1
-
 extern float t, dt;
 extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
 extern Vector rates;
@@ -73,3 +71,4 @@ void calibrateAccel() { print("Skip accel calibrating\n"); };
 void printIMUCalibration() { print("cal: N/A\n"); };
 void printIMUInfo() {};
 void printWiFiInfo() {};
+void configWiFi(bool, const char*, const char*) { print("Skip WiFi config\n"); };
--- a/tools/grab_log.py
+++ b/tools/grab_log.py
@@ -13,7 +13,7 @@ lines = []

 print('Downloading log...')
 count = 0
-dev.write('log\n'.encode())
+dev.write('log dump\n'.encode())
 while True:
    line = dev.readline()
    if not line:
--- a/tools/log.py
+++ b/tools/log.py
@@ -43,6 +43,7 @@ records = [record for record in records if record[0] != 0]

 print(f'Received records: {len(records)}')

+os.makedirs(f'{DIR}/log', exist_ok=True)
 log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
 log.write(header.encode() + b'\n')
 for record in records:
Author	SHA1	Message	Date
Oleg Kalachev	9fd35ba361	Simplify lpf filter code Begin with zero instead of the initializing value, as the latter doesn't make much sense in practice, but complicates the code much.	2026-01-24 09:43:46 +03:00
Oleg Kalachev	ca50f75576	Various minor fixes	2026-01-24 09:34:16 +03:00
Oleg Kalachev	e47a31f981	Fix mavlink parameter set acknowledgement value If the parameter is integer the acknowledgement should contain the rounded value.	2026-01-24 09:32:49 +03:00
Oleg Kalachev	7ad3022798	Add parameter for configuring gyro bias lpf + reset the filter on `reset` command	2026-01-24 09:31:32 +03:00
Oleg Kalachev	5b654e4d8e	Update ESP32-Core to 3.3.6	2026-01-23 02:41:43 +03:00
Oleg Kalachev	cf10ec6161	Update MAVLink-Arduino to 2.0.16	2026-01-23 01:11:35 +03:00
Oleg Kalachev	6d01cd2e79	Make failsafe configurable using parameters SF_RC_LOSS_TIME - time without rc to activate failsafe. SD_DESCEND_TIME - total time to decrease the throttle to zero. Make controlTime nan on the start to simplify the logic.	2026-01-22 23:57:52 +03:00
Oleg Kalachev	0abb18c616	Make parameter names case-insensitive + minor fix	2026-01-22 23:11:47 +03:00
Oleg Kalachev	30326a5662	Add parameters for configuring the mavlink subsystem MAV_SYS_ID - mavlink system id. MAV_RATE_SLOW - rate of slow telemetry (e. g. heartbeats). MAV_RATE_FAST - rate of fast telemetry (e. g. attitude, imu data).	2026-01-22 23:04:45 +03:00
Oleg Kalachev	dd3575174b	Add wifi configuration using parameters and cli Add console commands to setup wifi. Add a parameter for choosing between STA and AP mode. Add parameters for udp ports. Remove WIFI_ENABLED macro.	2026-01-22 22:58:43 +03:00
Oleg Kalachev	c0f3301da4	Support integer parameters in addition to floats The variable pointer is stored as a union field. If `.integer` field is true, then integer pointer should be used. Interfaces to parameters (cli and mavlink) keep working using floats. Setting a non-finite value to int parameter will cause an error. `.value` field is renamed to `.cache`.	2026-01-22 22:54:05 +03:00
a.golubtsov	a6bad3a69b	Add log dir creation before log writing	2026-01-22 17:56:23 +03:00
Oleg Kalachev	9a9bd07251	Add correct attitude estimation video to the usage article	2026-01-15 23:46:23 +03:00
Oleg Kalachev	28f5855a57	Re-arrange control.ino declarations to make a bit more sensible So the control command is above the PID controllers.	2026-01-13 17:43:53 +03:00
Oleg Kalachev	7e24ee30f7	Documentation and book updates Improve the main list of features. Use lowercase imu variable for consistency with the firmware code. Minor fixes.	2026-01-13 17:26:40 +03:00
Oleg Kalachev	2a8faf5759	Fix logo svg slightly	2026-01-08 19:45:08 +03:00