Crédits:
21 janv. 2013
Here is a video of the Quadcopter I made. The base used is a V929 on which I replaced the electronic with a micro-controller ATmega328P.
The various modules are soldered on a prototyping board. The unit is a bit heavy but the aircraft take off anyway.
Arduino pro mini module 16Mhz is used as the micro-controller. The voltage regulator is not used because the 3.7V lipo battery is connected directly above through capacitors to stabilize it.
The motors are brushed type and are controlled by PWM (256 levels of accuracy) by SI2302 MOSFET which I added diodes.
Two modules are used as sensors, MPU6050 (accelerometer / gyroscope) and HMC5883L (magnetometer). This also includes the 3.3V voltage regulator supplying 2.4G module (nrf24L01p). Currently, only the gyroscope is useful because the quad is in "acrobatic" mode, ie it is the angular velocity of each axis is controlled by a PID.
The radio FM 72 Mhz is modified. The high frequency part is deactivated and replaced by a amplified nRF24L01+ 2.4G module. The PPM signal is decoded to retrieve the position of the joysticks. It also contains an arduino pro mini 16Mhz module. The whole thing is powered by a LiPo 7.4V. The 5v regulator is included on the arduino module. Another 3.3v regulator is used to supply the module nRF24L01 +. The communication protocol is very simple, the state of the sticks is stored across 4 values. The hardware CRC is enabled. The frame is sent only once, even if the communication fails because the acknowledgment is disabled.
The aircraft flew correctly, although it varies sometimes a little when you want to rotate around it. This will be corrected by changing the values of PID. The next step is that the Quadcopter stabilized by itself. The remote control will control the angle and not the angular velocity. I also would like to changed micro-controller taking a ARM7 stm32F103 for more computing power. But is only available in LQFP package, it will require to make a real PCB.