Comment by Chris Anderson on January 6, 2009 at 8:33am

Excellent! Many thanks for sharing it. Any special hardware requirements or just the standard Accel+2gyros+servo driver+BT GPS?

Comment by Sami Finnila on January 6, 2009 at 8:36am

No, just the standard ones so there's no altitude hold ATM.

Comment by Harrison on January 6, 2009 at 12:47pm

Are these the unreleased new gyros or are they the ones you can order from Lego today?

Also would it be reasonable to use a heading hold gyro from a heli on the elevator channel to maintain altitude?

Comment by Sami Finnila on January 6, 2009 at 1:06pm

These are the already available HiTechnic rate gyros and everything else you'd need is also already commercially available.

There are already gyros (both roll and pitch) holding the plane level with the aid of the accelerometer. But unless you can perfectly set your throttle and trim you aircraft the altitude will change over time and for a fully functional autopilot you'll want to be able to set 3D waypoints. I have source for an I2C barometer (SCP1000-D11) but it's stripped from this version of the NXT AutoPilot since this sensor requires some home brewing in order to work with NXT.

3D bluetooth GPS modules are also becoming relatively cheap so I'll try and add one to this project so that we can finally have a fully functional Lego autopilot which is built with commercially available parts.

Comment by Chris Anderson on January 6, 2009 at 1:26pm

Sami,

You can get the altitude reading from the GPS, so no need for a barometric sensor.

Comment by Sami Finnila on January 6, 2009 at 1:36pm

Yes that's what I meant but the GPS I use supports only RMC so there's no altitude coming out of it and for a 3D GPS I need a new parser and a new control loop but in the mean while I can provide the barometer code if someone decides to pick that path; My matriculation examinations begin within a month or so and therefore I won't publish any updates for the next 3-4 months so that's why I mentioned the barometer path. Sorry for the confusion.

Comment by Robert Drone on July 25, 2009 at 7:34am

What about these?;

http://web.mac.com/ryo_watanabe/iWeb/Ryo's%20Holiday/Gyro%20Sensor.html

http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=93

http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=101

Comment by Sami Finnila on July 26, 2009 at 5:38am

Those might do. I have stopped developing the NXT AutoPilot because I ran out of funds and intrest for the project. One thing that I recommend you do is make it with full 6DOF IMU. I.e. you'll have to put the servo controller and accelerometer onto the same port (in order to get 3 gyros connected) which will slow down the refresh rate of both of these a little but with 3 gyros slowing down the accelerometer a little is nothing to worry about. Other than that my code should be up to the task.

Comment by Robert Drone on July 29, 2009 at 3:15pm

Thanks for the info!

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