We have already dealt with Quadcopter flight controllers in previous articles, apart from that, there are lots of remote controlled quadcopters based on many microprocessors. Oscarliang.com have come out with an idea of running a Linux machine on a quadcopter with the help of raspberry pi.
To mark a difference between a quadcopter and a PiCopter, let me tell you that PiCopter is a remote controlled quadcopter based on a Raspberry Pi. The compact size and computation power of raspberry pi compared to most micro-controllers actually make it a good flight controller and it handles all the flight control without using a micro controller like Arduino.
The project is using only standard Raspbian as many people doubt about the credibility of Raspberry Pi, that it might not run in real time. It means you just hav to update the motors with at least 10 Hz. Otherwise it is possible to face problem while getting sensor data and sending commands to the motor in the right timing and that leads to instability.
The projects require MPU6050 and special Motor controllers. It allows I2C communication protocol. 4x Robbe Roxxy 2827/34 Brushless Motor, Raspberry Pi, Arduino and RFM12 for Radio transmission over ttyUSB0, MPU6050 Gyro and ACC Motion. With all the Parts, the whole quadcopter only weights about 1 KG including battery.
You don’t have to get indulged in other stuffs as the Raspberry Pi controls everything. It means you don’t need standard Quadcopter Board or any other micro controller for flight control. Arduino is used as an interface between the Radio transmission and the RPI. The Radio System works on 433MHZ and there is no need for PWM signal
The software was written in C++, and the sensor sampling frequency is about 300 Hz to 500 Hz. The motors are controlled at 50 Hz and most of the Software processing time is spent on waiting for sensor data due to the slowness of I2C. The actual computation doesn’t take much time even though everything is down in floating point numbers.
Raspberry Pi VS Arduino
The project is successful and it is running amazing with the Raspberry Pi. It is highly compatible even without a real time kernel. To power the quadcopter and for real time stability, it is adjusted with an Arduino Pro Mini or equivalent microprocessor. An I2C or SPI connection with the Raspberry Pi is also built for control as this allows more room on the Raspberry Pi to run the expensive video recording. One of the best advantage that Raspberry Pi has over Arduino is its much greater computation power, thus more complicated and better stabilization algorithms can be run on the Raspberry Pi.
The video is available on the website
Filed Under: Reviews