Re: AW: [Paparazzi-devel] new board

[nisma]

Hi,
i´m planning to produce a small uav board having 3d accelerometer,
3x gyro, 2x pressure sensor and one voltage sensor.
I´m currently unsure, if using the digital (spi) gyro sensors and
using the two spare adc´s/channel for pressure and one accelerometer axis
using the spare cpu power inside the gps 
or using the lower costs analog gyros and a dspic processor. Both solutions
have 12 bit accuracy. Further for some sensors, like pressure
the resolution is increased adding a pwm generated bias for selecting 
the measurement window inside the sensor range.
The board will be 4-6 layers. Because the gps sensor can output
the raw gps data at 50-100 HZ, without processing it.
The source code for processing and kalman filtering is provided, so i
actually search for a optional external cpu for the gps position extraction
at higher update rate. Any of you´r smart guys have a suggestion in this
area ? Actually my preference is to use the digital gyro sensors and
additionally using one digital spi inclinometer (mems - heat based - 1hz
update rate) because it´s cheap and helps fusing the two accelerometers
in order to reduce the drift and vibrations errors in case of non electric
engine. Actually, no active magnetometer is planned, because it´s possible
to use the gps with really better results, and as gps backup, the small
spi 3d-magnetometer from the pni corp can be used placing it far away from
the electric motors and servo.

Any comments will be welcome. If someone is interrested in this developement
or want to be a beta tester, don´t esitate to contact me directly.

Regards
Chris

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