Have been having a lot of trouble using the Sonar so decided to do a power filter and shielded cable. DId the cable with copper tape and shrink tube and have a ground plug going to the APM2 ground. Added a 100 micro-farad cap and a 100 ohm resistor to the sonar unit per the Maxbotics site.
Behavior is much improved. A couple of questions though.
1) Does it matter where on the APM2 I go to ground with the cable shield? I am powering the APM2 off its own BEC and the motors off the ESCs. Currently I am taking the ground to a ground pin in the AN row of connectors.
2) Does the attached graph look right? The first part of the flight appears to be pretty tight between baro and Sonar, but partway through it gets very weird looking. Any ideas?
It seems to be some spikes, but does it fly well with that ?
I have a even worse problem, here in sweden it starting to get chilly outside and as soon i take the quad outside and put it into ALT_Hold it starts to climb away.
The logs says it's reading 20cm all the time.
The things I have done:
1. Dual Shielded USB cable
2. Power-Filter 10-Ohm, 100µF
4. 4x10-Ohm for heat around the element.
Here is without anything done:
And here is as good as it gets with everything above done:
It seems to have problem with the cold outside, even when I made the "heat-mod".
Might be so, I have ordered a new sonar, LV-EZ0 from a local reseller in Sweden. Should arrive today, so it should be up for testing soon.
The cold issue is a known problem:
I have a replacement sensor, but it's Spring now so can't check it.
I have tested the new LV-EZ0 today in about 10C temperature outside.
The results are really good !
Didnt have to touch the throttle for the whole flight. There is some variation in altitude but I think that's an arducopter setting because the sonar looks really good.
I just noticed that I used a 10-Ohm for the power filter. Maybe that's the thing creating the offset. Should change that to a 100-Ohm, ASAP :)
Sonar is the red and baro is the green