Raspiolt : yet Another Rpi cape flight controller WIP, designed in China

Hi, dear Diydrones members, today I’m happy to demo yet another raspberry based Ardupilot compatible flight controller expansinon board design.

Features:

Pixhawk compatible Power/GPS module interface
Integrated ublox m8n GNSS module
CSI camera ribbon compatible PCB profile
PX4IO forked project for dedicated PWM I/O with STM32 MCU
Emlid™ Navio+ inspired solution for ardupilot HAL
FULLY open source software and HARDWARE

Goals:

Single package for FPV solution
Yocto distro with minimum firmware footprint
Deliver in May, 2015

Why we did this because we believe in open sourced project will be a great tool to learn from the best, and to be even better. We are young Chinese engineers, please no stereotype.

I’ve been assist @zhangkaiqi working on this project for a while now. We had a breadboard wiring prototype flying happily now and we want to push this endeavor a litter further. As earlier Navio+ test reports from Emlid shows that PWM consumed about 20% of RPI B+’s cpu time, we want to test another solution by putting PX4IO (pixhawk’s co-processor part) on RPi.And we are inspired by @PatrickDuffy’s (Diydrones member, not twitter) FPV solution on Rpi with ubnt™, so we want to build a flight controller has all the good features we can get from a Rpi, so we combined them together.

Today we have the first PCB design sign-offed to the fab, and later this week hope to have a smoking test (first time power on a PCBA). We hope people with talent to join us with software design process and we hopefully to send some samples to volunteered engineers, testers and early bird costumers.

We promise to open source all project files, including Eagle Cad schematic/layouts, after we have the first batch PCBA running complete. We need initial product generate some revenue to support out later developments.

I’ll update this thread for the project, please commit for your ideas and feature request.

Thanks for people who contributed to this community made this possible.

@Philip, @ScienceBeer is the principle designer of Raspilot. According to design the hardware is compatible, and according to Emlid’s recent software development, it will run in realtime.

@Randy, many thanks . Hope this design will deliver.

@Pritam, early prototype will hand-soldered. It will be very time consuming and error prone, so it will not meet our confidence for flying responsiblely. We welcome you for further contact.

@Emlid, a clone production will be much easier, with not layout required.

@Stephen, we are work in progress. Emlid is worth trying.

@Pritam, I have a DJI s900, and I have never give a thought to putting a parachute on it. I have seen a EDF solution, with Lipo battery, bench test looks good... I think it worth give a trial for super-cap driven EDF solution. With Linux on board, design a parachute ejection policy will be easier, I hope.

@David, OSD with Rpi Gstreamer is already tested and working good. Refer to @PatrickDuffy’s posts.

@Andrew, we are using PX4IO version with i2c connection. We had a early paper design to build a SPI-UARTs hub, but not implemented in this verison. We are considering to build a USB-Serial converter with static /dev/tty numbering adapter for peripherals.

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Comments

Developer

Andrew Tridgell July 28, 2015 at 2:32pm

Lucas is on the drones-discuss list, plus he is often on the mumble chat (http://dev.ardupilot.com/wiki/ardupilot-mumble-server/)

You are right that the internal AK8963 compass isn't great, although mostly because it is hard to get it away from the other electronics. The best compass option seems to be a HMC5983 external, placed well away from the other electronics.
Developer

Andrew Tridgell July 28, 2015 at 5:03am

If you have an opportunity to change sensors it may be worth looking at the mpu9250 to allow for the possibility of sampling the accels at 4kHz, which would improve vibration tolerance.

Thanks for the pointer to the github fork. I notice it doesn't seem to be rebasing on ardupilot master and instead is more manually being kept up to date? It would be great to get support for this board into the standard repo at some point, and that will be easier if it is rebased regularly.
Pritam Ghanghas July 24, 2015 at 1:48am

Sorry for jumping in. I though Jerry was not replying. But Then I saw that he has replied today. He will have much better info.
Pritam Ghanghas July 24, 2015 at 1:45am

@Andrew,

Jerry was kind enough to send me one of the first engineering prototypes. I will check the onboard sensors in the evening. I am still preparing a craft to test it out. He had sent me GPS module unsoldered and advised against soldering it. It seems on this particular revision there is some random interference if you solder the GPS. But I think he has produced new revisions both with and without GPS on board and these new boards don't have this problem. Jerry may be able to shed more light on the matter but i guess he is too busy hacking new revisions.

You may be able to guess the state of affairs form github page. https://github.com/raspilot/ardupilot-raspilot#树莓派飞控raspilot

There is a little bit of chinese here and there but google translate solves it pretty well.
Developer

Andrew Tridgell July 24, 2015 at 1:10am

I'm also interested in how this is going, as this would be the first Linux based board that can run ArduPilot and can potentially support manual failsafe for fixed wing aircraft in case of software failure on the RPi.

One thing I forgot to ask previously is how you plan on uploading the firmware on the stm32. On the PX4v1 the FMU communicates with the IO controller via I2C, but it loads new firmware onto the IO controller via a serial port. That serial port is then used as a telemetry port when not being used to load firmware.

Being able to update the firmware on the stm32 is pretty important so that bug fixes can be applied.

I'm also interested to know what sensors you have on the cape. Is it a MPU9250 IMU like the NavIO? What other sensors?

Once you get the board going it would be good to add support for it in the standard build. I'd suggest you work with Lucas on that. Lucas is the new Linux port maintainer for ArduPilot (see README.md in the git repo).

Cheers, Tridge

App Showcase
Jerry Giant July 24, 2015 at 12:47am

@barban now a new revision is done. i'll update the info soon.
Pritam Ghanghas April 8, 2015 at 2:07pm

@Jerry

I can't PM you untill you accept my friend request on diydrones.
Jerry Giant April 1, 2015 at 9:29am

@Philip, @ScienceBeer is the principle designer of Raspilot. According to design the hardware is compatible, and according to Emlid’s recent software development, it will run in realtime.

@Randy, many thanks . Hope this design will deliver.

@Pritam, early prototype will hand-soldered. It will be very time consuming and error prone, so it will not meet our confidence for flying responsiblely. We welcome you for further contact.

@Emlid, a clone production will be much easier, with not layout required.

@Stephen, we are work in progress. Emlid is worth trying.

@Pritam, I have a DJI s900, and I have never give a thought to putting a parachute on it. I have seen a EDF solution, with Lipo battery, bench test looks good... I think it worth give a trial for super-cap driven EDF solution. With Linux on board, design a parachute ejection policy will be easier, I hope.

@David, OSD with Rpi Gstreamer is already tested and working good. Refer to @PatrickDuffy’s posts.

@Andrew, we are using PX4IO version with i2c connection. We had a early paper design to build a SPI-UARTs hub, but not implemented in this verison. We are considering to build a USB-Serial converter with static /dev/tty numbering adapter for peripherals.
Developer

Andrew Tridgell April 1, 2015 at 9:22am

Nice to see another Linux solution!

are you talking to the STM32 using a UART (like Pixhawk)? If so, how many UARTs will end up being available for peripherals?
David Skipper April 1, 2015 at 6:39am

@ Jerry,

Will this have build in OSD ?

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