Personally I'd like to see a
low cost,
all-in-one autopilot for small foamies. My $0.02:
- Attitude estimation: Invensense IMU-3000. It's a 3-axis gyro with
built-in quaternion-based sensor fusion (I'm assuming Kalman filtering, as DCM is obviously a matrix algorithm, and I haven't seen a quaternion-based complementary filter either). Two I2C ports connect to an external 3-axis accelerometer and an MCU. The chip reads the accelerometer values directly without intervention from the MCU, which can read attitude estimates on the other I2C. Couldn't be simpler, and you don't need a high-powered MCU. It's not out yet, but we're promised that evaluation boards are coming soon. Perhaps Sparkfun can inquire with Invensense directly?
http://www.invensense.com/mems/gyro/imu3000.html
- MCU: I love STM32, but anything ARM is nice. Too many electrical engineers just slap whatever chip has good electrical characteristics onto a board without thinking of the needs of us poor software developers. We need a proper compiler, darnit! This means AVR, ARM, PIC24, MSP430. No MSP430x, GCC doesn't work (no really, it doesn't, you may think it does but holy crap don't get me started). Stuff like PIC18 is right out imho. Since the IMU-3000 does the sensor fusion, the micro needs only to implement some relatively simple control loops. Given the fact that an STM32 or LPC costs about the same as a capable AVR, I'd go for the ARM - that way I can run an embedded rtos like eCos so that I can at least have memory protection. Sucks to have your plane fall out of the sky because some led blinking code is trying to write to *random. Also, the first person to suggest Arduino will be stabbed with a pencil :3
- Telemetry: why pay craploads of money for an XBee module when you can just put a CC1101 433MHz radio and SMA connector on the board? This way you can have plane-to-ground and plane-to-plane communication: flying multi-hop networks, yay! Note that the CC1101 is a packet radio, so you clock in your data and press send, very easy to work with. Personally I'd even do manual control over such a digital link, saves a receiver and PWM/PPM decoding logic.
- Shields/extending: I really like the small footprint of the XBees. Seeed is selling a GPS bee (
http://www.seeedstudio.com/depot/gps-be ... p-560.html), and they also have a bluetooth bee. Having one or two %sbee connectors on the board would allow for stuff like adding extra sensors/actuators such as compass, magnetometer, pitot tube, temperature, camera, gps, led lighting, etc.
- Stick on some debug leds, and one or user two buttons. Four servo channels and one or two motor controls? Four for quad copters of course.
Now given these requirements I think the whole thing should be possible to sell for about $100. I'm not sure what the IMU-3000 will cost, but their sales blurb quotes ~$3.50 for large quantities - so they can't be more than 10 bucks if you buy a few. Add to that a capable MCU, accelerometer, CC1101 ($5), and you can easliy have a parts list of under $50. Add another $50 for development cost, PCB manufacturing, labor, profit. I'm not a professional electrical engineer at all, so I'm not sure if I'm talking out of my *** here, please correct me if I'm sounding completely unreasonable.
Now let's see what that would mean for low-cost UAV enthusiasts like me:
Multiplex EasyStar clone: $60 (i.e.
http://www.hobbyking.com/hobbyking/stor ... To_Fly_EPO)
Awesome SparkFun autopilot: $100
GPS: $40
Battery, shipping, stuff: $50
Presto, a fully working UAV for $250.
