What is the smallest ArduCopter capable flight controller?

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The one made by Sky Rocket that`s in the new Sky Viper:

https://youtu.be/3RdEELDIeVs?t=17m25s

This is about where Tridge shows the size of the controller board.

Many of the flight controllers typically associated with Betaflight, iNav, etc, can be flashed to arducopter.  I use a Kakute F7 all-in-one...but there are many others.  All these are FAR smaller and lighter and integrated than the Pixhawk world.  A quick calculation for me is that I saved 175 grams using the Kakute F7 as opposed to a Pixhawk, OSD, power sensor, telemetry, etc etc.

Comparable to the Crius all-in-one vs the APM except without connectors. You saved about SIX ounces! You have a controller with soldered on (by you) wires; time IS money. What happens when it fails? You will have to re-do the soldering; the wires. No easy/quick way to swap out the controller. Was/is it really worth it?

The added integration is the PDB, the BEC, and OSD chip which places constraints on the system.

In addition, there is the maintenance of the ArduPilot/ArduCopter code! ArduCopter is in a constant state of flux... Not criticizing you Bill; just making observations and wondering if it was worth the effort?!

Note that these new F7 compact controllers came out with a ICM20602 AND an additional MPU6000. The mfgrs bad mouthed the ICM20602 saying it was "noisy" and to use the one you "like the best". Turns out monkey-see-monkey-do. The had all, typically, copied each others schematics as was the case with the Pixhawk clones, Turns out they had NO decoupling/noise filtering on the power input to the chip which is MANDATORY. The sensor, which oscillates at about 30khz,, was getting harmonic noise from the switching regulator. 

Note too that you cannot really get 32khz of discrete samples from the ICM20689 (or MPU6000, or ICM20602) at 32khz. It CAN transfer at that data rate, but a good portion of the samples are redundant; the accelerometer samples at 4khz; gyro at 8khz.

Would you please post some pics of the wired up controller?

Lastly, there is a slew of new F7 based controllers (and other CPUs) now supported in the ArduPilot code running ChibiOS; see the "libraries\AP_HAL_ChibiOS" sub-directory.

Good luck! Have a good flight!


Bill Salopek said:

Many of the flight controllers typically associated with Betaflight, iNav, etc, can be flashed to arducopter.  I use a Kakute F7 all-in-one...but there are many others.  All these are FAR smaller and lighter and integrated than the Pixhawk world.  A quick calculation for me is that I saved 175 grams using the Kakute F7 as opposed to a Pixhawk, OSD, power sensor, telemetry, etc etc.

It's funny how this post is from 9/2017. BTW, here's a Kakute F7 all wired up.

Hate to be a pest, but could you please take a closeup or two perhaps from each side. When I zoom in on this pic it is pretty much pixelated obscuring detail...

Just curious; where is the battery going to go?

Thanks again!

Here is something you might find interesting.  As a software/hardware engineer I know it is bad practice to mount lots of ceramic caps in parallel right next to each other due to possible cracking from thermal stress. This usage seems to be prevalent right now in ESCs using banks of cheap small ceramic caps instead of the old electrolytic can caps; BAD practice!

Take a look at the Holybro (maker of the Kakute F7) Tekko32. Specifically zoom in on the rows of caps. They add hot melt glue to try to secure them (what a joke), but as can be seen by zooming in, most of the solder joints have failed/cracked! I wonder how many HUNDREDS of these are out there! Add this to my info on the 20602!

yeah! It is funny how this post originally in 2017 pops up on the radar! Back then we had no STM32F7xxx MCUs.

I'm going to send an email to Holybro about this ASAP!

See on their website here.



Thomas Butler said:

Hate to be a pest, but could you please take a closeup or two perhaps from each side. When I zoom in on this pic it is pretty much pixelated obscuring detail...

Just curious; where is the battery going to go?

Thanks again!

Will do. BTW, here's a pic of a toasted Tekko32 that I had attached to a Kakute F4 V2:

Holy moly from Holybro! ha! Not really funny! Sorry to see that...

@Bill,

Hey great pics. FYI I am in the process of developing a FC using the Atmel/Microship SAM E70, and it is always helpful to see how people wire up their flight stacks. Thanks again!

Interesting how Holybro is using HOT-MELT glue on the row of capacitors! That's a really BAD practice and typical of the kind of BS that comes out of China. What ARE they thinking? It's as bad as when the Chinese added melamine powder to baby formula to up the chemical content of protein! The hot-melt hides the fact there is a problem with their soldering of ceramic caps in parallel; in itself is a bad practice because it is highly subject to solder cracking from thermal stress if the pads are not oversized. I found their Tekko32 4-in-1 has severe cracking on the row of caps (it can be seen in their product image on their web site), and in the pic I posted with hot-melt on the left solder joints, the first caps' right solder joint is cracked.

I would carefully peel off that glue and see if they are hiding solder joint failure! if it is cracked, re-solder the caps.

The cracking is partly caused by the solder pads on the capacitor being too small. Examination of other Holybro products shows much larger pads for the capacitors...Typically the failure a row of caps layout is in cracking of the caps themselves.

Those icky power cable solder joints needed a bit more flux!

Interesting layout mistake is in the wiring from the FC to the ESC, They should have reversed the pin order on one connector so the wires transfer straight; prob is why there is another unpopulated connector on the top of that PCB. 

I'd like to see someone open up a Holybro Pixhawk4 for inspection! NOT saying they do, but they might have a systemic problem with component solder joints.

I wonder what caused the frying of the 4-in-1?

she was really unstable with the stock ArduCopter PIDs.

Thomas Butler said:

I wonder what caused the frying of the 4-in-1?

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