Well, almost... few more things will be added in the next hardware version.This is a project that started about 3 years ago when I began building a P-47 rc airplane. Back then I decided that if it is worth doing it is also worth overdoing, so I began working on a small on board computer that would cycle the landing gear hatch doors when as it is being retracted. Since then plane never progressed forward but the simple on-board computer did.Here is what it looks like today:
and on the back:
What You can see there are:- LISY300AL with IDG500 gyros- MMA7260Q triple axis acceleration sensor- HMC6343 3 axis magnetic sensor / tilt compensated compass and additionla 3 axis acceleration sensor- SCP1000 pressure sensor - used for altitude estimate- FC30TR orientation sensor - used for calibration and in-flight attitude corrections- 4Hz 50 Channel GPS + Serantel antenna based on u-blox UBX-G5010 chip- microSD card for data logging- xBee for wireless uplink- 4 optically isolated PWM rc servo channels booth for input and output with ESD protection- SEPIC DC to DC converter - will sustain full board operation down to 1V left on the battery- high speed I2C communication expansion port- CAN communication port- all controlled from a dsPIC microAll of that on a credit card size board!Obvious things that are missing (will be added in next version):- airspeed sensor- landing gear retracts air tank pressure sensor- battery level and fuel level sensing capability (booth for electric and nitro planes)- few more PWM channels (with intended micro change, I should be able to go up to 12 pwm output channels and 6 in!)- floating point capable processor to speed up code executionCurrently the board was tested with slightly modified version of Ben Levitt's MatrixPilot code.In parallel some ground work was laid down to create more sophisticated sensor fusion algorithms through an extended Kahlman filter, so far basic functionality gives pitch and roll readings (based on accelerometers and gyros) with yaw pulled from both the compass and gps. If time allows, future version will "fuse" all of the available sensors creating a robust IMU as a base for a UAV project.
Everything looks fine so far, but i will suggest to use the GPS and the Xbee apart. I also suggest an airspeed sensor in order to make it "All in one". ;-)
Is there any interference between the Xbee and the board ? (in particular, do the transmissions of the Xbee effect the output from the gyro circuits ?). We have had to be careful about that when adding Xbees onto the Red UAV DevBoards.
so far I'm briefly planning with TMS320F28335 - it has up to 18 pwm output capability, 6 of those are shared with 32 bit capture inputs if I remember correctly.
What processor do you plan on using in the future? I am looking for a processor which has maximum native PWM capability. I haven't been able to find any processors which had that, and all the other connectivity options I would like - so I've been considering using an FPGA to take care of input/output PWM, and having a register interface between the FPGA and uC.
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