Yes I do have a foam over the baro. It is actualy beneath the baro as the baro sensor is on the bottom side of the board 
I have experimented with it a lot, tried different amount and different kinds of the foam. I have come to a conclusion that baro alt is changing when the 3.3V BEC temperature changes.
I have enabled baro temperature compensation learning as per https://ardupilot.org/copter/docs/common-baro-temp-comp.html but TCAL_BARO_EXP was not changed from zero. I even tried setting it to a non-zero value, but it was getting reset to zero.
I have also seen occasional horizon drift - not sure whether it is caused by temperature, hence asking about your issue.
Bottom side? Of course you can mount the controller anyway you like but just to be sure the baro is on the same side as the USB connector right? I happen to have that side mounted up.
FWIW-I have not yet realized a temperature problem on this Flight Controller. Others for sure (Omni F4 nano).
Mine is a normal Kakute F7, not mini. I jumped this thread because google found that someone else is having temperature related issues with a Kakute.
Ah OK. I have one of those also and itās been pretty Stable.
I was considering buying an F7 mini for my new project, but after reading this thread and some others and considering my previous experience with Kakute I am tending to buy an H743-slim. Though it is very new and may have its own issues.
I am tired to fight with my OmnibusNanoV6 and its limitations, I ordered a Matek H743 Mini.
I will report when I got it.
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I re-purposed the Omni Nano and put it in a Plane.
Arducopter should be ported for these FCs which cost half the matek. Perhaps the 405 is already compatible with the FW 405 for matek. However, a 20x20 F7 with barometer and 5 UARTs at 23 USD would be great!
It might be if it could actually run Ardupilot. The link doesnāt work but itās an F722 from the link description. Not enough memory. Considering he overall cost of a quad copter the difference between a $28 FC (there are some that run Ardupilot) and a $50 H7 doesnāt seem significant. And the $50 H7 has an SD card. Your choices are an Omni Nano, Kakute F7 Mini (V2), a Matek H743-Mini or a iFlight Beast. But the later doesnāt support an external compass.
i corrected the link, unfortunately on hakrc there is not much documentation, for example there is an FC that supports arducopter but it is not documented. There is also the f405 which could work with FW matek 405
Yes, there are many F405ās supported. I just commented that the F722 doesnāt have the minimum flash to run Arducopter. Even 1MB is feature limiting and those have 512k.
I mounted the Matek H743 Mini on my 3 inch Copter using the provided silicon grommets and M3 nylon screws and nuts but I have lot of vibration and the Copter has attitude drift.
I had to try better mounting.
This is vibrations from first IMU (ICM-20602), those from second IMU (MPU6000) are only slightly better.
@anbello -I just completed a sub 250g 5" with a Matek H743-Mini and am pretty happy with the 1st flight. I also used the silicon grommets supplied but they are stacked on another set that came with the 4-in1. This is the ICM-20602, the MPU6000 is a bit lower.
I think what also helped was using M2.5 fasteners to give it a bit more compliance. The M3ās fit pretty tight in the grommets.
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@dkemxr Thanks for reporting. What do you mean for fasteners? (problems of english understanding)
I used 4 long nylon screws, on this I stacked the 4-in1 with its grommets and the Matek with its grommets, on top of all 4 nylon nuts.
I think the problem could be that I used M3 screws, as you said too tight in the grommets.
Anyway a sub 250g 5 inch is a really cool thing. Congrats!
Can I know which frame and which motors for this 5 inch?
@anbello I used M2.5 screws (fasteners). I wanted to use plastic but couldnāt find any smaller than M3. Not the best photo but you can see whatās going on. Plastic spacer below the ESC then the red grommet above the ESC and the grommet in the FC. A long screw and a lock nut. I realize this āfloatsā the ESC also but everything is so small and light weight I donāt think itās problem.
I used this frame and BetaFPV 1404 3800kV motors with 5.1x2.5 tri-blade props.
A note about the frame. The ESC battery solder pads was an interference fit with the aluminum standoffs. I turned them down and put shrink tube on to insulate them. I also carefully ground away some of the tab.
Powered by a 3500mah 2S Li-ion pack (ZOHD I use for a plane) incredibly it flew for 27 minutes in my house consuming 2475mah.
Thanks to @wicked1 for the confidence to go with the Aikon 4-in1! Despite Aikon saying (in an email) itās not stable on 2S it works fine.
I could not get ESC passhthru to work with Arducopter. I tried a few different versions of BLHelisuite incl the latest and no-go. I had to flash Betaflight back so I could reverse 2 motors. Telemetry works and am using it for the notch filter and total current.
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Thanks for the details! I will probably be building something similar later this year.
Do you have any of the 950mah 2s lipo packs? I wonder how long it would fly w/ one of those. LiIonās can be difficult at timesā¦ If you donāt care about a long flight, it would be faster to charge a parallel bunch of lipos.
I donāt have any 2S Lipo packs yet, Iāll have to buy a couple and try them out. The closest I have is a 3S 850mah but it kind of defeats the purpose. It would be like the 3" I had on 4S. That was a dumb idea.
Hey I actually do have a 2S battery. Itās a 1300mah I use sometimes for the R9 module on my Tx. I have drained this pack way below advised voltage a few times but Iāll give it a try!!
OK, more data. I flew the 2S 1300mah pack and itās very nimble at that weight (206g). I tried to fly as aggressive as I could in the house w/o pissing off my wife 
14 minutes at 1054 mah. Current and voltage are now well calibrated. So with a 950mah pack flying to 800mah >10 minutes I would say.
Iām really liking this kit of parts!
Awesome, thanks! Now if only I can get my gimbal to weigh 50 grams, Iād be setā¦
Having said that, I just weighed itā¦ 100 grams including the camera. Iām assuming you weighed your copter w/ a camera, so, subtract the runcam split, which isnāt much. Then I am also willing to give up my yaw axis, which is a relatively heavy motor. Itās close! But not quite under the legal limit.
@dkemxr I re-mounted the 4-in-1 + FC stack with shorter plastic screw and only one grommet, the Matek one, I have a stiffer stack but with less vibration, always less then 15 and no clipping.
Perhaps the longer plastic screws amplify vibrations instead of dampening them.
Now I would like to know if you tested your 5" in Althold and with what results.
Did you put foam on the baro? How much?
In my Althold test I see not so good behavior, I read good things about the DPS310 baro so I expected better behavior.
I also tried to do a Barometer Temperature Compensation, Maybe I have to try again.
I attach a graph.
