I just noticed this at the Chinese on-line retailer, ThanksBuyer.com

They are pricing the bundled versions attractively.  Obviously made to compete against the APM micro 3.1

Flight controller

FC bundled with power supply

FC, power supply, GPS unit

If anyone makes the leap, perhaps you could keep us informed on your experiences.

Happy flying all!!

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Well, I'll be,..   It works..   Turns out it doesn't like the RDF900 modem..  The modem is good, if I unplug the receiver it works, they just won't work together..  that is very odd..  I'm able to connect to the RDF900 from mission planner with another plugged into my PC..  but the dragonlink receiver won't work..  if I unplug the modem, the draginlink works..  

the shape of the fc its like the pixhawk !

Hello David,

I'm looking for a bit of help or at least confirmation.

I have one of the APM mini pros I got off of eBay. It flys okay except for ALT Hold. When I engage that it bounces and starts an erratic climb or it bounces and starts an erratic descent and lands. I've reset the controller several times, clearing parameters and eeprom but the problem persists. The thing that concerns me is that the vsi in APM planner will oscillate around zero constantly while the controller is sitting on my bench (with or without the controller being covered by foam).

The oscillation is small, a mm or two off of zero (not sure what the scale is, I'm guessing 0 to 25 feet per minute) and it is either positive or negative.

Also, on the bench the altimeter changes constantly. It shows .5 to 1 m excursions (rough estimate) over 20 second or so intervals.

My other APM boards don't do this, at least not nearly as frequently.

Q. I'm wondering if you see this same oscillation on your mini pros and whether your uavs are stable in alt hold despite this?

Q. If you do or did see poor performance in alt hold, how did you fix it?

I've not messed with mid throttle settings or pids or the like and it could be that I'm misinterpreting the oscillations as the cause of the poor alt hold performance. Those setting are my next move but my gut, and my experience as a commercial pilot, tells me these readings shouldn't be this variable, especially sitting on the bench.

I've researched this quite a bit on the web and have come across some concerns mainly centered around vibes and light but my bench test and the foam should rule these out, at least I think they should.

Any insight you can give would be greatly appreciated.

Thanks in advance,

Eric
Hi Eric, don't know if anyone's replied to your Q. Yet or if you have fixed it but I get similar oscillations in alt. On the bench and they are around the same I don't think the sensors are all that accurate independent of each other but together they do a good job of position hold etc. it sounds like the sensor is having a hard time adjusting to the difference between the air pressure etc where it is stored and the field. It is just a possibility. Sometimes they need a bit of time outdoors to adjust before they perform.
The other thing it may be is the PID tuning or throttle mid position. Check your throttle mid position while hovering and make sure it's in that mid position when in alt hold. If you increase throttle to much or drop too low even in alt hold it will make it increase or decrease in altitude. Getting your throttle mid position sorted then having a go at adjusting your PIDs would be the next step after leaving it outdoors to adjust before flight. If you need any more help let me know I have a little experience with these now and apart from a couple issues around power I've found the mini APM Pro FC a good one. By the way, what frame and motor size etc are you using?

Hello Michael, thanks for the reply.

I've written a lot here somewhat because you've been nice enough to ask but also it helps me chart my next steps.  Feel free to help where you're not exhausted from reading.

I have the Diatone FPV250 with 2206s from Hobby King (Baby Beasts I think they're called) and I have a Diatone Silver #17 which is a racing quad with Emax 1806s.  The former is overpowered I believe and the latter might be a bit less overpowered. 

I tried the mid throttle position thing last night but my flight log download wasn't successful (first time doing that.  I think I was gettng real time data, not in flight data).  As I've never analyzed logs before I suspect I'm doing it all wrong.  What I was seeing appear on the screen was some intelligible text and the rest gibberish.   End result, I haven't identified what my mid throttle position setting should be in order to set it in APM software.

When I attempted alt hold in my basement with the FPV250 I paid careful attention to the quad's actions.  I'm now suspecting that the mid throttle thing might be a big contributor.  On two or three trials the quad, when alt hold was switched on, simply descended, jumping a bit on way down, to rest on the floor.  This was from roughly 5 feet.  My hover throttle position was in the neighborhood of 40% throw which makes me suspect I'm overpowered.  The overpower thing I think I understand is what throws off the mid throttle "expectation" of the controller.

I'll have to devote a little more time to understandind exactly the data gathering process in order to understand what my mid throttle setting should be.  Once I get that potential issue addressed, I'll do as you suggest and start working the PIDs.

Which is another learning curve for me.  My PID setting has been all trial and error and I stop when my copters fly reasonably well.  I'll have to devote more time to understanding there as well.

All this to say that I'm hopeful/suspecting that it is a setup issue, not a hardware issue.  The bummer is that some of these controllers just work and others just don't.  Given the home grown nature of all this I'm never quite sure if its me, the (usually knockoff) hardware, or a combination of the two.

Any help you can offer I"m eager to hear. 

I'm focussing on eliminating some concerns:

1. mid throttle setting.

2. vibrations (which I've somewhat addressed but have not concentrated on as my other copters don't have that problem and I've not taken taken extraordinary measures other than trying to balance props).

3. dynamic airflow impacting the barometer (the props are by definition near the FC but I do have the foam installed...hopefully that's enough)

4. PID tuning.

Thanks for your help.

Waltec

Hi Waltek, from the sound of it I would concentrate on two main factors.
1. Set your mid throttle setting in configuration set up for a start because before it can do any good with your other modes it needs to be pretty well right. Go to the extended tuning or extended parameters section, (I'm not near my mission planner so forgive me if I aren't giving the exact name of these locations) but in the tuning page your first page I think is the basic tuning it's like the second or third heading from the top, it should show settings like if your copter is sluggish slide to left if copter is twitchy slide to right, on that page it should have a throttle hover slide bar. If you are not up at half throttle to hover slide the slider higher to the right. If you then hover test and its above slide it left until you get it to hover on mid throttle. after that remember when you put it into your alt hold make sure its in that mid range when you enter the mode.
Another thing after you have the mid throttle sorted enter tuning mode, not auto tune, tune mode when arm it you hold the throttle down and right keep holding it until the light goes from standard arm color to flashing. Take off and maintain a steady hover keeping it as steady as possible at one height in one spot. Then land and disarm. Take off again and see how well it hovers. If it is good great if not do it again. Best in a still indoor area where the prop wind isn't pushing it around and best not doing it in any wind if outdoors.
2. After completing these two things if you still have trouble it's time for PID tuning. I normally start by getting the setting that makes it either more sluggish or more crisp response found in the basic tuning I think, one of the top headings in config tuning page. Sometimes that can make a big difference because it actually alters PID characteristics without needing to go through the whole PID tuning process.
When you gave it flying about right for your style not too twitchy not too sluggish and if you still gave issues with the alt hold then it's time to go to your basic tuning page for PIDs with the stabilise PIDs loiter PIDs and throttle, etc. if your copter is flying OK in stabilise mode but not in alt hold you can sometimes either retune the stabilise PIDs which from the sound of the way you said it's bouncing on landing that's where I'd start. Tuning PIDs is a bit tricky and I'm out of time to explain right now, just try starting with those things and let me know how you go and I'll help as much as I can.
Awesome feedback. After I repair a couple of pins that broke when I hit my ceiling on another failed alt hold attempt, I'll get after this. I'll let you know what happens.
Ah yes repairs, I know the feeling. Just Friday I had my brand new mini APM pro hex with GoPro & 3axis gimbal suddenly trigger failsafe when I was only ten meters from it. Oh joy. Interference from something maybe, result was I dropped throttle before it hit a tree branch above before realising it was rising due to failsafe, (ended in a salt water death below. Destroyed 99% of that $1500. Set up. :(

Anyway you say you hit the ceiling indoors when trying alt hold. I would never try go intoalt hold or GPS modes while indoors. I know the barometer is what holds alt but in the settings I believe it does have options as to how much the GPS can be used to contribute to its altitude. I may have it confused with pos hold but just a thought.
So have you tested the other modes like loiter pos hold? If these are all working it narrows down the problem a little.
But as I said earlier set mid throttle- hover tune by holding arm for 30seconds until lights flashing, take off hold a steady hover in stabilise mode, maintaining altitude and position as much as possible. Throttle down to land and disarm, re-arm and test, if better great otherwise try again until maintaining that steady hover. After these are working and you think it's ready for alt hold test get satellite lock, take off and go to the alt you want lower throttle to mid then activate alt hold. If you increase throttle over the dead zone it will rise, same if you lower below dead zone will descend. Alt hold only holds while in that mid hover dead zone and I find it is reliant on having good PID settings in stab. Mode. If you need help tuning you PIDs later I can be of some help but it's really something you'll learn the basics from others but it's not until you do it many times that you get a good feel for the different behaviour from the changes. But always start with P then I then D then P again fine tuning I and D again, you can do this many times before figuring it out. Best to start with those other things if you have it flying reasonably already then let me know which craft you're setting and we can find the average settings being used on other peoples of the same size, it can help a little sometimes as a starting point, other times you have to just do it yourself.

By the way are you using a standard foam from the manufacturer or your own? I had an issue with a NAZE32 which would always ascend rapidly because I had a type of foam that wasn't doing a good job. Make sure it's that dark grey type, although I've used other types too with success but one type was just too porous or something.
Solved. Using a power module and a 5v Bec on RC end solved this issue on this mini APM pro. Others work fine using Bec from esc's with Bec 5v.
Okay. I do believe you've sorted me out. I ignored my concern about the erratic vsi and worked on the mid throttle setting. I've achieved better alt hold as well as decent loiter. Not enough time to do a thorough job but I'm sure I'm on the right path. I'll report back one I've been able to do more of what you've suggested. Thanks again for the push/insight.
Huge bummer on your hex, sorry to hear it.

I purchased one of the APM Mini pro's.  I am trying to connect the osd and sik radio to it but based on the images I've seen, it seems there is a discrepancy about where you connect the OSD,  I've seen it being shown connected to the UART0 port and one showing it connected to the Telemetry port.  Can someone confirm where to connect these two items.  thanks 

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