hello every one..
1.i have got the same problem as andrew. as soon as i switch the quad to alt hold mode it climbs up very fast.i have tested the sensor in the cli mode. i got pretty decent distance values. i have also tested the sensor using arduino and got the same distance values. i have used a lv ez4 and apm with 2560. i have been trying to solve the problem but i am not able to understand where the problem is comming from. i used ardupilotmissionplanner.
2. i want to try the ardupirates code.but i donot know whether ardupirates code supports 2560.
thank you
Replies
Thats all I could think of as I had the same problem as you and centering the throttle when I switched resolved it. I am sure there will be a patch or something for it lateron.
Ardupirates code should run fine on 2560, but I don't think it will do you much good. I think your sonar is getting interference from your motors or esc's. Is it mounted close to the motors or esc's ?
Can you get a log of a flight where the alt_hold doesn't work so we can look at the actual sonar data the apm gets while flying ?
See also : http://diydrones.com/forum/topics/fixed-my-sonar-alt-hold
When you are hovering, check your thottle stick percentage, it might simply be that your throttle position is above center point and therefor telling the quad to change altitude. If I fly 12x4.5 props, hover throttle is ok and quad sits at the height. If I fly 10x4.5 props, my thottle input is at around 68% at hover so when I switch to alt hold, the quad starts to rise, so i center my throttle and then it holds ok.