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Pumpkin drop event

Electrohub yo-yo on Baro and aux channel 2 not working?

#1
Hello Ladies and Gents! So built my first quadcopter​
IMAG0065.jpg IMAG0067.jpg

Now this is the exact setup the guys here at FT recommend. All electronics are from RTF Quads with MW Pimp my Flip 1.5 running 2.3 software.The "pimp" is I added on the mag and baro to the FC. Receiver is Spektrum AR610 and running a Spektrum DX6 (NOT THE DX6i, the new 2014 edition DX6)

Have a few questions Im hoping to get answered by one of you fine people more knowledgeable than I.

#1 When I engage the baro on it for poops and giggles it really starts to "yo-yo" about +/- 4ft from where I engage it at. So wondering if this a software issue, tuning issue, or throttle application issue.

#2 I had no problem assigning the gear channel on the AR610 to aux 1 on the FC and the switch I wanted on my DX6 (went with B). Problem is I wired the aux 1 on AR610 to the aux 2 on FC and assigned it another 3way switch (in this case H) but nothing. I checked the switch levels in wingui so I know the assigned switch for B is working but I am getting nothing for the aux 2 channel on the FC.

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Any ideas comments concerns here? I wanna thank everyone in advanced who may or may not comment on this so if I dont thank you personally I apologize.

Im having a blast learning to fly this and have been showing it off to the guys at the fire dept who are impressed with it. (and those guys are damn hard to impress! lol)

Have a great day everyone.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#2
For the Baro, that's pretty typical. for an untuned loop it's going to bounce quite a bit, and it might be pretty violent in the swings -- possibly even unstable. The sensor might also be uncovered (yes it has the case and that helps) but you might consider putting a small piece of gauze, loose cotton ball or open-cell (breatheable) foam over it to protect it from light or airflow -- it's surprisingly sensitve to both!

If you haven't yet, tune your roll/pitch/yaw PID's, then your Altitude PI. RTFQ's setup is nice about being stable in most conditions without much adjustment, but I've never seen one well tuned out of the box -- There's a HEAUGE differance between stable and tuned. You'll want all 4 of those control loops tuned and one of the self-level modes active (Horizon or Angle) before you should attempt to tune Baro, otherwise you might be fighting poor tuning in one of the other loops.

That being said, don't expect stellar results. the baro control loops on multiwii are weak and will drift quite a bit in the 2-3' range. Better tuning will slow that drift, but it's not really goign to give you much better.


For the Aux channel . . . having a hard time following you, but, what I think you are saying -- you've set up your radio with one switch to the "Gear" channel and one to the "Flaps" channel (I know it's not called that, but two AUX1's becomes confusing fast)

- If you plug the "Gear" into the flip "Aux1" you see a change on the multiwii conf Aux1.
- If you plug the "Flaps" into the flip "Aux2" you don't see a change on the multiwii conffig GUI.
- If you plug the "Flaps" into the flip "Aux1" you see a change on the multiwii conf Aux1.

Correct? If you pluged the "Gear" into the flip "Aux2" would you see a change in the GUI?

If that's the case, then you've got an issue with the AUX2 connector -- double check the soldering on the inner most pin. It might need to be reflowed. There's also a fair chance you've got a hardware defect.

If I've misunderstood you . . . sorry. Double check your "monitor" screen to see that when you flip a switch, the command changes on the outgoing channel, then check the wires. If you've got a servo handy, pop that into the "Flaps" port and you should be able to see it move in response to the switch . . . and possibly narrow down where the disconnect is.
 

makattack

Winter is coming
Moderator
Mentor
#3
I'm new to all this as well, and haven't any experience with multiwii and the barometer. Looking at your pictures, I'm guessing the daughter board with those sensors is inside the flip case which should protect the barometer from wind and sun, but I know with apm, the cases also have foam padding over the barometer to really isolate it from wind.

My guess is that if it keeps changing altitude in a yoyo like manner, the tuning may fix that, maybe by lowering the gains so it doesn't over correct.

Have you tried swapping the gear and aux channels to see if you can isolate what might be causing you to not see input on the other channel?

I was slow in typing from my phone, and see that Dan has posted much more complete suggestions. Great stuff from one of the experts here!
 
Last edited:

jhitesma

Some guy in the desert
Mentor
#4
The yoyo on baro is typical for the default tuning. Even with proper tuning though MW doesn't do a very good altitude hold and will drift within about 2-3 feet. Even the naze32 with a better quality baro sensor (though the BMP180 used on the pimp board is considerably better than the old BMP085 sensors the naze still uses an even better sensor) doesn't do a very good altitude hold.

The best writeup I found on tuning altitude hold is here:
http://www.multi-rotor.co.uk/index.php?topic=5090.0

The MW Wiki also has good info on how to tune it though the link above goes into the why behind the method a bit better:
http://www.multiwii.com/wiki/index.php?title=Altitude_PID

I spent quite a few packs getting it tuned on mine and got it better...but it still never really held well. Shielding the sensor helps...but the bottom line is the MW control scheme just isn't very good.

Using the same lower accurate BMP085 sensor with no shielding installed in the same airframe but using Tau Labs and no tuning my quad holds altitude better than I can hold it manually. Though the tradeoff is that Tau only does altitude hold as a separate flight mode where it works in vario mode with throttle now controlling altitude instead of speed (like a DJI setup.) MW/Naze are great for flying...but not that great for more advanced flight modes.