I posted the photo of my 1″x1″ NanoFlyer board couple of weeks back. I have managed to port MultiWii 2.2 code to this board and the quadcopter flies quite nicely! The home made transmitter and quadcopter control board are both using the NanoFlyer board. The transmitter board is missing the intertial sensors (accelerometer, gyro, magnetometer).
The Flight Control Board:
The flight control board has ATMega128RFA1 low power 2.4 GHz transceiver and 8-bit microcontroller SoC as the brain. The gyro sensor is ITG3200, accelerometer is BMA180 and HMC5883L is the magnetometer. The serial debug/programming port is exposed on the side to upload new code and to configure MultWii paramters with the MultiWii configurator GUI. MultiWii 2.2 has the serial codes heavily modified and I have not been successful to get the serial over radio code working yet. The analog and digital I/O ports are exposed in the back of the board as shown in the NanoFlyer board post. I am using the brushed motor driver board to drive the four tiny brushed motor. I had to try couple of MOSFET models befure I could get the right one to drive the tiny brushed motors I bought. It turns out ZXMN3F30FHTA by Zetex diodes worked best for me. Couple of other MOSFETs I tried did not drive the motors with enough power on 3.7v lipo. I am going to try three other types of MOSFETS to see how those work.
The frame, motors and propellers are for a UDI mini quadcopter. I bought those as spare parts from banggood.com
The homemade transmitter:
The transmitter is made out of two two thumb joysticks and the NanoFlyer board. I had to modify one of the thumb joysticks to use as the throttle control, as thumbsticks are usually spring centered. I opened up one and cut of two sides of plastic balancer to release the spring pressure on the throttle. Here is a picture:
In the picture (left side) you can see the white plastic part has two cut-off flat edges for the throttle control. However, thumb joysticks are not designed for very precise control. So it takes a lot of getting used to. I had to lower the RC expo to 0.20 (20%) to get a comfortable control for now. Thumb joysticks comes with one push button. I used each of those to control the AUX1 and AUX2 channel data. So it is basically a 6 channel transmitter/transceiver and can certainly be expanded to more channels. The later plan is to add an OLED display on the transmitter to get real-time data from the quadcopter contol board.
Here is a quick video of the tiny quadcopter flying. I am still trying to get used to the controls with thumb joysticks.