Amazingly Tiny QuadRotor: Daedalus CrazyCopter

The quadrotor itself is organised around the main CPU. The job of this CPU is to acquire the physical measurement given by the gyroscopes and accelerometers and to control the motors to keep the copter stable. This is done by a regulation loop which controls the motors speed 250 times per second. 
          

            
The computer runs control and telemetry programs. The control program reads the input from a game-pad and sends control commands to the copter. There are programs that can configure the quadrotor regulation parameters and log the measurements in order to make easier to tune the regulation.
         

             
The top of the board contains the sensors and the control/communication electronic:

• The JTAG/Serial connector permit to program the processor and to communicate debug messages.
• The Main CPU is a STM32 Cortex-M3. It is clocked at 64MHz from the internal oscillator.
• The 2 Axis X-Y Gyro is an invensense IDG500. 
• The 1 Axis Z gyro is an invensense ISZ500. 
• The 2.4GHz Radio is based on an RF24L01+ chip from Nordic Semiconductor. It is actually a breakout board sold by SparkFun. The radio is connected to the CPU via a SPI port.
• The 3 Axis Accelerometer is a SMB380 from Bosch. It is connected to the CPU via an I²C bus.

          

         
About power supply:

• The charge connector accepts 5V and permits to charge the battery
• The power switch permits to power the copter either from the charge connector or from the battery.
• The 5V step-up permits to increase the power voltage from the 3~4V coming from the battery to 5V.
• The two 3.3V linear regulators, reduces the 5V to power the copter electronic. The digital and analog 3.3V are generated independently. This was made to reduce the noise on the analog components.
• Finally at the four sides there are the motors transistors. The power for the motors pass on the top and bottom of the part of PCB that hold the motors.
• The battery charging chip is just at the right of the 3.3V regulators. It is a classical MAX1555.

          

          
The idea with the step-up was to get a more stable voltage when the battery is depleted and also to remove some of the noise coming from the motor electonic. Anyway, this boars is capable to work without by using 2.8V linear regulators instead. 
           

            
The motors and propellers are taken from a Silverlit X-twin plane. They are powered by the battery voltage.
The distance between the motors (horizontally and vertically) is around 8 cm and the total weight is around 20 g.