Hello and happy new year.

I decided that I wanted to have retractable landing gear on my hexacopter, but I didn't want to pay the full price for a ready made set (£50/$80). With all the parts I gathered, it came to about £12/$18, so that's quite a saving to be made.

I made a write up article to help others to make their own in hope that we can begin to develop the Ardupilot to enable automatic retracting landing gear like on the DJI systems A2 flight controller. I hope that Droidplanner will have a dedicated button to enable/disable auto landing gear, and also to set the altitude trigger, using either the barometer or gps or optical flow sensors. If anyone has undertaken this suggestion already, i'd be grateful for some links posted in the comments. 

Many thanks and happy flying

Tutorial Link: http://dalybulge.blogspot.co.uk/

Views: 5580

Comment by Whirligig on January 2, 2015 at 8:46pm

For what its worth, this gentleman built an altitude activated landing gear for his helicopter using sonar and arduino with a sketch provided:


I can imagine a Taranis radio can do this using a Vario sensor and adding some altitude limits to turn on or off the retracts channel.

Comment by benbojangles on January 2, 2015 at 9:51pm

nice thought to have the transmitter take care of auto switching. 

Comment by benbojangles on January 2, 2015 at 10:16pm

Can't we just do a simple if statement in a separate tab in Arduino ide?

Something like:

//------------------------------AUto REtract sketch etc

def x = 3; // set an altitude to engage retract switch

void_loop() {;

 if apm_alt = <x; // what is the correct variable fro alt?

 retract_ch = 1; //I made up retract_ch but it could be defined, right?


 retract_ch = 0;


Anyhow, I have no idea what the codes are for Arduino Ardupilot as I haven't trawled through the code as there is quite a lot of it. right now, I only know how to comment/uncomment code to allow me to use ppm/pwm  etc.

Comment by benbojangles on January 2, 2015 at 10:44pm

I like the idea of using a separate arduino to control the retracts and also reading a sonar HC-SR04 sensor. I figure the Arduino pro mini and sonar connected to the 5v ubec would work, and has got me rubbing the old beard.

Comment by Justin Stiltner on January 3, 2015 at 1:45am

I would be happy if we could make the autopilot lower the gear when it does a landing command for whatever reason (loss link, and failsafe included).  A command that actually says gear up or down would be great for mission planning, but currently if you loose link you will be landing on your camera.

Comment by Stuart Brookes on January 3, 2015 at 2:41am

Nice Idea on the angle adjustment. I used some similar retacts to make my own. I wanted to make the angle wider as you have done but didn't think of the way you have. Might open up an old one I killed (not flight or use related...the retracts I used used cheese metal for the bit that moved so I drilled and tapped a thread in but was too lazy to remove from the retract while drilling and drilled the lead screw inside! wally!).

Good work

Comment by benbojangles on January 3, 2015 at 3:25am

Justin - I think, with a separate Arduino running the landing gear code, it would be separate from any failure of the main ardupilot, it would always lower the landing gear when below the sonar detected height. :)

Comment by Rob_Lefebvre on January 3, 2015 at 6:04am

If the Ardupilot fails, I think the landing gear being up is the least of your problems. ;)

I sure would't slave landing gear to a simple sonar sensor.  It will constantly be going up and down in flight at random times. You at least need to employ intelligent signal filtering.

Comment by Tim Hughes on January 3, 2015 at 9:11am

Nice idea.  What legs are you using for the retracts?

Comment by benbojangles on January 3, 2015 at 9:14am

legs are the ones which came with the s550 frame. Rob you star!


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