January 2013 Update

Update on Project

So far I have purchased several pieces of electronics and have a vague plan for the flight system.  The raspberry pi has 2xUSB ports and a GPIO. The GPIO has supports one UART, one I2C and two SPI. For the flight system I require the ability to control servos and have knowledge of the helicopters orientation and how fast it is moving, accelerating. The helicopter also needs to be able to detect obstacles.

The address these I am going to develop three systems as detailed below.

Orientation & Position System

To detect the helicopters position I have decided to have a suit of 4 sensors. These are:

  • GPS (connected via USB initally)
  • Compass 3-D connected via I2C – Honeywell HMC5883 Module Three-Axis Digital Compass HMC5883L S...
  • Accelerometer 3-D connected via SPI Analog Devices ADXL345
  • Pressure Gauge connected via SPI on ATmega328 microcontroller. Note not sure how much one will be able to read form the pressure, considering pressure varies with weather and typically changes from 101.325kPa to 100.748kPa in 40 meters of altitude at around sea level. The sensor I have purchased is a MS5611 high-resolution atmospheric pressure module height sensor IIC SPI 24-bit

 Obstacle Detection

Initially connected via the obstacles will be done solely using 6 (HC-SR04 range 4.5m) ultrasonic sensors measuring the distance to the obstacles. One will be mounted underneath to see if the helicopter has landed. The ultrasonic sensors with be connected to an Atmega328 microcontroller which will then be attached to the UART GPIO port on the raspberry pi. The Atmega328 SPI port will have the pressure sensor attached.

 

Flight Control System

The flight control system will adjust upto 7 servos that will control the blades and control surfaces of the helicopter. The 7 Servo Controller will be connected via one of the SPI ports.

SPI breakout board to control 7 servo motors,for AVR, arduino, PIC, Raspberry Pi Bitwizard.nl

Before tiring to run (fly) before I can walk (drive), I will start mount the system on a test buggy. The buggy I am going to use is an old toy I had and built as a kid. The buggy currently has some damage and needs a good clean and a bit of soldiering tlc etc. But should prove a good test platform before flying.