Update README.md

README.md

@@ -8,16 +8,85 @@ This is an Arduino library to build ESP32 / ESP32-S3 / RP2350 / RP2040 / STM32 f
 
 <img src="extras/img/madflight RP2040 flight controller.jpeg" title="madflight RP2040 flight controller" width="25%" /> <img src="extras/img/madflight drone.jpeg" title="madflight drone" width="19.6%" /> <img src="extras/img/madflight ESP32 flight controller.jpeg" title="madflight ESP32 flight controller" width="19.1%" />
 
-
 ## Feedback is Welcome
 
 I enjoy hacking with electronics and I'm attempting to write some decent code for this project. If you enjoy it as well, please leave some feedback in the form of Stars, Issues, Pull Requests, or Discussions. Thanks!
 
+## Required Hardware
+
+- [Development board](https://madflight.com/Controller-Boards/): 
+    - [RP2350/RP2040](https://madflight.com/Board-RP2040/) (e.g. Raspberry Pi Pico2)
+    - [ESP32-S3/ESP32](https://madflight.com/Board-ESP32/) (e.g. Espressiv ESP32-S3 DevKitC)
+    - [STM32](https://madflight.com/Board-STM32/) (e.g. Black Pill or a commercial flight controller)
+- [SPI IMU sensor](https://madflight.com/Sensor-Boards/) (BMI270, MPU9250, MPU6500, or MPU6000), if not available then use an I2C IMU sensor (MPU6050 or MPU9150) 
+- RC Receiver: ELRS, CRSF, SBUS, DMSX, or PPM
+- BEC or DC-DC converter to power your board from a battery
+- ESC (OneShot125 or 50-490Hz PWM) and/or servos (50-490Hz PWM)
+
+## Optional Hardware
+
+- GPS Module (Serial)
+- Barometer (I2C BMP280, MS5611)
+- Magnetometer (I2C QMC5883L)
+- Current/Voltage Sensor (ADC or I2C INA226)
+- [Optical Flow Sensor](https://github.com/qqqlab/ESP32-Optical-Flow) (I2C)
 
 ## Getting Started
 
-See [madflight.com](https://madflight.com) for detailed instructions to get flying. 
+1. Connect the required hardware to your controller board: 
+    - See [RP2350/RP2040 pinout and instructions](https://madflight.com/Board-RP2040/)
+    - -or- [ESP32-S3/ESP32 pinout and instructions](https://madflight.com/Board-ESP32/)
+    - -or- [STM32 pinout and instructions](https://madflight.com/Board-STM32/)
+    - Connect your IMU (gyro/acceleration) sensor as shown [here](https://madflight.com/).
+ - Install the madflight library in Arduino IDE. (Menu Tools->Manage Libraries, then search for "madflight")
+ - Open example Quadcopter.ino in the Arduino IDE.
+ - If you're not using a default pinout then setup your board pinout in the CUSTOM PINS section.
+ - Edit the HARDWARE section to enable the connected peripherals
+ - Compile and upload Quadcopter.ino to your board. Connect the Serial Monitor at 115200 baud and check the messages. Type `help` to see the available CLI commands.
+ - Use CLI print commands like `pimu`, `pgyro`, `proll` to Check that IMU sensor and AHRS are working correctly. 
+ - IMPORTANT: Use CLI `calimu` and `calmag` to calibate the sensors.
+ - Connect radio receiver to your development board according to the configured pins.
+ - Edit the RC RECEIVER section. Either match you RC equipment to the settings, or change the settings to match your RC equipment. 
+ - Check your radio setup: Use CLI `ppwm` and `pradio` to show pwm and scaled radio values.
+ - Connect motors (no props) and battery and check that motor outputs are working correctly. For debugging, use CLI `pmot` to show motor output.
+ - Mount props, go to an wide open space, and FLY!FLY!
+
+## Safety First!!!
+
+By default madflight has these safety features enabled:
+
+- Motors only rotate when armed.
+- Arming Procedure: set throttle low then flip the arm switch from disarmed to armed.
+- Kill Switch: when the arm switch is in the disarm position, disarm and stop motors until re-armed.
+- Failsafe: when radio connection is lost, disarm and stop motors until re-armed.
+- Armed Low Throttle: motors run at low speed, to give visible armed indication.
+- LED armed/disarmed indicator.
+
+## Software Design
 
+- Keep it simple!!!
+- Based on [dRehmFlight](https://github.com/nickrehm/dRehmFlight)
+- Coded primarily for readability, then for speed and code size.
+- No external dependencies, all modules are included in the `src/madflight` directory.
+- The madflight flight controller runs standard `setup()` and `loop()`.
+- It mainly uses plain Arduino functionality: Serial, Wire, and SPI. One custom hardware dependent library is used for PWM. Therefor, it can fairly easily ported to other 32 bit microcontrollers that support the Arduino framework. Also porting to other build environments like PlatformIO or CMake should not be a huge effort.
+- The following modules are used:
+    - `imu` Inertial Measurement Unit, retrieves accelerometer, gyroscope, and magnetometer sensor data
+    - `ahrs` Attitude Heading Reference System, estimates roll, yaw, pitch
+    - `rcin` RC INput, retrieves RC receiver data
+    - `control` PID controller and output mixer
+    - `out` Output to motors and servos
+    - `mag` Magnetometer (external)
+    - `baro` Barometer
+    - `gps` GPS receiver
+    - `bb` Black Box data logger
+    - `cli` Command Line Interface for debugging, configuration and calibration
+    - `cfg` Read and save configuration to flash
+    - `hw` Hardware specific code for STM32, RP2040 and ESP32
+- Most modules are interfaced through a global object, for example the `imu` object has property `imu.gx` which is the current gyro x-axis rate in degrees per second for the selected IMU chip.
+- For a quick overview of the objects, see header `src/madflight/interfaces.h` which defines the module interfaces.
+- The module implementations are in subdirectories of the `src/madflight` directory. Here you find the module header file, e.g. `src/madflight/imu/imu.h`. In the `extras` directory your find test programs for the modules, e.g. `extras/TestMadflight/imu.ino`.
+- The module files are usually header only, that is, the header also includes the implemention.
 
 ## Disclaimer