I am less than thrilled with the wiring for this board that has been shown here. It seems like it would be more prone to solder fatigue failures than it really needs to be. And multicopter and VTOLS have more than enough vibration to cause that fatigue. In particular the 13x3 pin connector for the ESC and servo outputs puts a lot of cantilevered bending load on a single row of pins soldered into the board.

Yes, I admit to being paranoid about things like this, but some of that is from having things fail in the past.

So, I went looking for a solder type printed circuit "protoboard" that would make the required wiring easy, and give better structural support to the connectors. There are a lot of boards set up to have a DIP device in the center, with lands for connection to the pins spreading out to the sides, and then power bus rails along the edges. Unfortunately, almost all the ones I found had a .2" gap between the end of the signal land and the closest power bus rail, so our normal RC type connector would not fit.

However, I found a few with the right layout and this one looks the best:

https://www.amazon.com/gp/product/B0040Z6OYC

It has the power bus and signal land spacing to fit the servo type connectors. The photo shows where the Teensy would fit. (yellow outline) as well as the trim lines to cut a minimal size board that would match all the wiring needed. (blue outline).

The Teensy could mount to soldered in header pins or a Teensy with pins could plug into female sockets soldered to the board. (easier, less hand soldering, but more potential failure points).

There would need to be only 2 jumper wires to get the 5V and ground lines over to the output connector busses. As shown, the 5V would only need to be .1" long to the PC land going across the end of the board. Or you could have a longer jumper going all the way across and a .1" shorter board. The ground jumper is just .2" long.

As shown, you can get 3 boards out of the big board, or with the longer 5v jumper, you could get 6.

I have one of the boards on order and it should be here in a few days. I will post some photos once I have a board set up.

Bob

For most of my builds, I use these with pin headers so the teensy is removable between different broken out proto boards: https://www.amazon.com/ELEGOO-Protot...dDbGljaz10cnVl

The default hardware setup is far from ideal, I admit. But will work for people new to soldering. It also reduces total weight and reduces confusion introduced when breaking out a board onto your own proto setup. It's only meant as a starting point, as the default code is intended to be modified for each unique use case. For more advanced setups, proto board is the way to go

Originally Posted by rcjetflyer2

I use these with pin headers so the teensy is removable between different broken out proto boards: https://www.amazon.com/ELEGOO-Protot...dDbGljaz10cnVl

It looks like the boards you show do not have any lands.. just an array of holes, and all the wiring has to be added. The one I showed has lands to get almost all the wiring.

I think somebody with limited soldering experience would be best using a Teensy with pins, and plugging it into a socket on board once all the soldering is done... less chance of damaging the Teensy board.

I'm not going to get to the Magdwick 9DOF this week unfortunately.

But along those lines, one good thing to add to the documentation would be the coordinate system.

the link is not relevant

Originally Posted by grisham43

the link is not relevant

Your post would be a lot more relevant if you had bothered to tell us which of the many links in this thread you think is not relevant! As is, nobody has a clue what you are talking about.

Originally Posted by jihlein

I'm not going to get to the Magdwick 9DOF this week unfortunately.

But along those lines, one good thing to add to the documentation would be the coordinate system.

I've got my 9250 here, just needs to be soldered up. I have the 9dof madgwick code ready to go on my end. Coordinate system is already in the doc!

I know I said Friday for newest release, but life threw me some curveballs this week and I might need a few more days to get everything tested and documented

Any chance of a magnetometer calibration routine that doesn't require the airframe to be spun around? I recall arducopter getting that support so perhaps this FC has enough power for it also? Thinking of building some 5 foot wingspan planes and would feel a little awkward trying to spin it around before each flight.

Good to see some movement being made on the mag side of things.

Originally Posted by parky

I am less than thrilled with the wiring for this board that has been shown here. It seems like it would be more prone to solder fatigue failures than it really needs to be. And multicopter and VTOLS have more than enough vibration to cause that fatigue. In particular the 13x3 pin connector for the ESC and servo outputs puts a lot of cantilevered bending load on a single row of pins soldered into the board.

Bob, another consideration is that all those 90º headers weigh a fair bit.

What about a ribbon connector to remove the stress and filter vibration ?

Cheers
Nicholas

Originally Posted by RCvertt

Any chance of a magnetometer calibration routine that doesn't require the airframe to be spun around? I recall arducopter getting that support so perhaps this FC has enough power for it also? Thinking of building some 5 foot wingspan planes and would feel a little awkward trying to spin it around before each flight.

Good to see some movement being made on the mag side of things.

I think that should be doable--offset and scaling calibration (just like the gyro and accel) should suffice.

With all of that said, the only benefit of the 9250 will be accurate yaw orientation estimate. If you're planning on writing your own controller on yaw (as opposed to the default which just stabilizes yaw on rate setpoint for every controller type), then I suppose that is desirable. The 6050 attitude estimation is great as it is

Originally Posted by rcjetflyer2

With all of that said, the only benefit of the 9250 will be accurate yaw orientation estimate. If you're planning on writing your own controller on yaw (as opposed to the default which just stabilizes yaw on rate setpoint for every controller type), then I suppose that is desirable. The 6050 attitude estimation is great as it is

I have not looked in detail at the Madgwick filters yet., but how well will the attitude reference hold up with just gyro and accels given a few minutes of both high angular rates (at least 180 deg per second) and 3+ lateral G? Yes, it is a weird corner case, but on a plane with KK2.1.5 based Open Aero VTOL, it did result in some crashes.

Bob

Originally Posted by njacobs

Bob, another consideration is that all those 90º headers weigh a fair bit.

What about a ribbon connector to remove the stress and filter vibration ?

Cheers
Nicholas

Anything with a ribbon cable and connectors is also going to get heavy. I think the best thing to save weight would be to just have the number of connectors you really need. Putting male pins on the end of a ribbon cable would also be a bit problematic unless you had a separate PC board there.

I just got that solder protoboard I linked to before. It is pretty simple.. 1 sided board, no plated through holes, but looks like pretty nice fiberglass board and 1 oz copper, with nice wide lands. Totally reasonable. I will go wire up a Teensy and post photos in the next few days.

BTW, I did have some USB issues trying to talk to the Teensy board. Worked sometimes.. I thought I had messed up a board by soldering to it. Turns out that a USB hub that has been working fine for a lot of things did not want to work consistently with the Teensy. Connecting directly to the computer has been working fine,

As for the "computer at the field" concerns. I resurrected a 5+ year old 12" MacBook that I had not used in a few years. Its pretty slow and I had migrated to something faster for normal use. But it can compile and load dRhemFlight in about 5 seconds, and its not that valuable anymore, and its really light to just keep with me in a backpack. The battery life is OK also.. still ran for a few hours playing a bunch of YouTube videos. So, not my ideal situation for tweaking a new plane, but tolerable for now. I would still love a little plug in terminal to directly change gains, but that is a huge effort do set up and code. Low priority.. which means probably never. ;-)

bob

Originally Posted by parky

Anything with a ribbon cable and connectors is also going to get heavy.

Send all the signals via Bluetooth.
(TIC!)

Hi All,

Posting in case this is of interest here. I've had some luck porting the Arduino based code over to STM32F411CE Blackpill (https://stm32-base.org/boards/STM32F...Pill-V2.0.html) and an MPU9250 breakout board. I'm using this Arduino core https://github.com/stm32duino/Arduino_Core_STM32. SPI is used to talk to the MPU9250, fast SCLK speed is set to 6MHz.

The advantage of this core is the long list of STM32 parts it covers (https://github.com/stm32duino/Arduin...aster/variants) including the F411CE Blackpill, STMF405RG (found on the many F4 flight controller boards) and more. The disadvantage is the sometimes lower maturity level of the core and libraries relative to Teensy.

The main advantages to me are the migration path to existing low cost flight controller hardware, and the availability of hardware debugging (Teensy does not support hardware debugging that I know of, just embedded print statements). I'm comfortable with soldering and breadboards but an available flight controller would make things easier. If I retarget to STM32F405RG the code "should" run on a Sparky2 board. I have a few of these, you can still find them here for $30 (https://www.motionrc.com/products/ta...ght-controller). I would like to get MPU6000 running as this would open up a host of current low cost FC options, Matex targets, etc.

Nick, I realize this may be a distraction from the Teensy based project you've started here so will start a new thread if you would prefer. I will be posting the code up on GitHub as soon as I get a chance to clean things up a bit. I started with the code here, not too much modification was needed to move it over to this core but as always the devil is in the details

Best Regards,
George

Originally Posted by parky

I have not looked in detail at the Madgwick filters yet., but how well will the attitude reference hold up with just gyro and accels given a few minutes of both high angular rates (at least 180 deg per second) and 3+ lateral G? Yes, it is a weird corner case, but on a plane with KK2.1.5 based Open Aero VTOL, it did result in some crashes.

Bob

Looks like OAV used complementary IMU fusion which is the simplest and least accurate attitude estimation technique. Madgwick will be much much better, and if there's any issues, you'll be able to increase the gyro and accel range in the next code release

I'll also be looking to replace madgwick with EKF farther on down the line for even better attitude estimate