fmadirect fs8 co-pilot sensor signals

[gta18]

Hi, does anybody here have played around the 4 windowed sensor of the fs8 copilot? pinouts maybe and communication protocol it uses?

it will be nice to incorporate this with the diy 2.4ghz tx/rx.

thanks
arnold

[ZAGNUT]

other than the sensors there is only an op-amp and a couple of caps in the circuit, very simple. all the hard work is done in the receiver itself. i did draw the schematic a long time ago and will look for it later today.



dave

[maxvtol]

FMA said you can use 3.3 or 5v in on the sensor, the outputs will be + or - mid voltage on the 2 outputs.

If you're looking at the sensor connector pins with the top facing up, the connector pins are Ground - Voltage - Pitch - Roll. The output is a little noisier than the ADC gyros I'm using, so you will probably have to average the signal and possibly put a little dead-band in there.

[gta18]

do we get like a pwm signal out of the pitch and roll pins?

[maxvtol]

do we get like a pwm signal out of the pitch and roll pins?

Not out of the sensor, it's just an analog signal. If you put 5v to the Ground and Voltage, you'll get 2.5v out of the output pins if the sensor is level to the horizon and not moving. If you move it around, the voltage will vary just like a signal out of an analog gyro.

[gta18]

Gotcha! so we get like 4 qudrants. What experiments have you done with it?

thanks

[maxvtol]

I'm using it on my quad tilt rotor. Heres my build log (http://www.rcgroups.com/forums/showthread.php?t=782929) , and my website www.vertiplane.com (http://www.vertiplane.com), and my thread for my vtol mixer (http://www.rcgroups.com/forums/showthread.php?t=701709).

I basically tied it into a Coridium ARMmite microcontroller (http://coridiumcorp.com/catalog/product_info.php?products_id=57) through the ADC pins, along with 3 ADC gyros. The ARMmite reads the PPM signal from a hacked Berg 4L receiver (http://www.castlecreations.com/products/berg_ms4l.html) mixes all the signals to send them out to the ESC's and servos.

I haven't done much testing with the FMA sensor alone, but that's next and it looks promising. In this video I was turning the FMA sensor on and off to test it, but I don't think the gyros and the FMA sensor together are necessary. The FMA sensor signal just needs to be calibrated to give level flight. The crash was caused by the BEC on one of the ESC's tripping out because the digital servos were using too much current.

Quad Tiltrotor Video (http://www.youtube.com/watch?v=GLMoKYmFsLY)

[gta18]

wow, nice vtol right there!
Am going to try interfacing the fma sensor with the 18f4455 pic. I was thinking of having two compare ports connected to the ppm signal from a rx to get the pulse train from it. How did you do yours?
thanks
arnold

[maxvtol]

Thanks.

The ARMmite is so fast, I'm just using a Do Loop to determine the PPM pulse edges and assigning the timer value to a variable. Once I've determined I've got a valid PPM string, I'll update the Rx data.

I'm getting the ADC data from the gyros and FMA sensor every 6 to 8msec and then mixing the data and updating the esc's and servos, this makes it very stable. Since the ARMmite's linear, I'm having to get the data samples and do the mixing between the PPM pulses.

It may not be very elegant, but it works.

Good luck with your project.