Which RaspberryPi Autopilot - Navio2 vs ERLE Brain2?

pixhawk

#1

The Pixhawk autopilot has provided a great platform and powers thousands of drones today. However it was released almost 3 years ago and has reached the limits in terms of processing power. So if you are looking for a autopilot platform that still uses the same dronecode framework you need to look elsewhere to perform more advanced tasks with your autopilot. This was usually achieved via a companion PC board such as the Odroid, leaving the pixhawk to just perform flight control.

However this last year two new projects have stood out by building a addon board for the raspberry Pi to turn your RPI into a arducopter compatible autopilot with loads more power than Pixhawk. Here we will compare the ERLE-Brain 2 (which is based off the Pixhawk Firecape board) from Erle Robotics in Spain, and the Navio2, from Emild from Latvia/ Hong Kong. However both of these auotpilot boards are also compatible with many other raspberri pi form factor boards such as the more powerful Odroid, or the bannapi and beaglebone single board computers.

What autopilots we compare

Size

Since both the Brain 2 and Navio2 are designed to fit onto your Raspberry Pi 2, the size ans weight are both negligible since the RPI 2 board is the largest and heaviest component. However the Navio is slightly smaller than the Erle-Brain 2.

Sensors

Here the Navio 2 and Erle-Brain 2 use slightly different approaches. The Navio 2, uses two 9 DOF IMU chips. Each chip includes a 3 axis gyroscope, 3 axis accelerometer and a 3 axis compass. On the other hand the Erle Brain 2 uses individual chips, so a 3 axis compass, a 3 axis accelerometer, and a 3 axis gyrocope. The advantage of having separate IMU sensors is that they are typically more sensitive as they are larger (do not need to cram 3 sensors into 1 chip. Hoever since the Navio2 uses two 9DOF IMU chips I am sure that both autopilot system will perform flawlessly in all robotics applications. You also have the option to change the scale of the IMU sensors, so if you are using your autopilot in high g force environments you can set the scale to $\pm$16G. However when you increase the scale, the actual sensitivity reduces.

Powering the autopilot

Both the boards make use of the APM power module to provide power to the board, and also to provide current and battery monitoring functionality.

Price

The Navio2 is sold for 190 USD, the board itself is 168, but you will need to also order the GPS antenna for an additional 12. Since the Navio2 has the GPS chip onboard you dont need to add a GPS module, but you will need to include the antenna. This brings the basic cost excluding the Raspberry Pi to 190USD. Adding a raspberry pi, and an APM power module and converting to GBP, the total cost of a Navio2 autopilot will be about £175 (not counting any VAT or possible import duties)

The Erle-Brain 2 on the other hand is only sold as a complete kit with the Raspberry Pi for 199.00€ excluding VAT. It does not include a GPS module out of the box you will need to add that, however since it uses the same UART and I2C connectors you can use any GPS module compatible with the pixhawk with the brain 2. So lets say we use a Ublox Neo 7 GPS module (£30), and converting the total to GPB, we come in at around £180.

Documentation

Since the Navio 2 is a new product, there is little documentation as of me writing this article, however in terms of the documentation available for the Navio+ (the predecessor to the Navio2) I would say that their documentation is a little easier to follow from a beginners point of view. So hopefully within a month or so the Navio2 documentation will be released.

Conclusions

So at the end of the day, both these options are very similar in terms of hardware, the only thing that will set these apart is the support offered by each manufacturer, and only time will tell. So far Navio2 does seem to be more popular currently. However with the release of the PXFmini from Erle robotics, they are now offering a much smaller autopilot board, which I imagine will turn into the Erle-Brain 3, which allows you to run your autopilot on the new raspberry Pi Zero (but its also compatible with raspberry Pi 2, and Odroid if you need more processing power) which could be a very good reason to switch to the smaller platform.

This is article I was just thinking out aloud in case anyone was wondering the same questions as me, so some things could be wrong, or outdated. If you do have any specific questions or corrections just let me know below.


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Pixhawk Fire Cape
#2

Thanks for putting this together @unmannedtech1!

A few remarks:

  • Erle Robotics technology has a fundamental open source and open hardware philosophy. The reasoning why the sensing and power electronics of both solutions is similar relies on this exact matter.
  • Price-wise comparisons are unfair. Erle-Brain 2 is a Linux autopilot including vibration damping, in-house setups, calibration and a protective case while Navio is a shield for the Raspberry Pi.
  • I’d argue the comments regarding popularity and community but I’m obviously biased ;).

I’m leaving here a link to the PXFmini. They’ll start shipping in about 10 days and as pointed out at the end of the article it’s definitely leaving other options behind.


#3

Thanks for your feedback, and I do agree that the PXFmini does look very cool, I have been in contact with you guys about selling your autopilots at our shop as they do seem like great options and I am very much looking forward to testing and promoting them when they arrive with me. If you feel I missed anything else about your autopilot please let me know and I will add it above.

As for the price, that is purely a matter of fact that both are similar in terms of what comes out of your pocket when you order one. That said I know that with the Navio you will need to spend some time setting up your raspberry Pi, and you will need make an enclosure, all of which does toake extra time, but the Erle-Brain 2 arrives ready built so you can get it working much faster.


#4

So the erle brain2 does NOT have vibration dampening included. Just some foam tape on one side to keep the board in place, not enough for dampening. Running it on a shake and vibe table, I noticed not much difference between the two. So keep that in mind that a clean Vib dampening plate will be needed.

I just purchased a couple navio2s, couple brain2s and a couple pxfminis. Between the navio and brain, I much prefer the design and build quality of the navio2. Better circuit board, silk screen and integrated gps neo8m, which is the best one out there at the moment. The one erle offers is the neo7 which is rubbish. I get hdop <2 indoors by a window and a fast acquisition time. If you go with the erle get a 8m from a different vendor, crius is pretty good.

The other flaw is that erle only includes a 8gb micros card which isn’t enough to run an update, you’ll max out the card and brick the unit. Flashing to a bigger card has helped. The case on the erle is also 3d printed in pla, so very diy and not very professional for what your paying.

Build quality between navio2 and brain2, the navio wins hands down. The navio2 includes a dedicated SMT F1 Chip, where the brain2 doesn’t, which means more load on the pi processor. I do like their pxfminis, but on a zero, it’s hitting 60% load so don’t plan on running much else. You can barely navigate the console it’s so bogged down (load of 4.0+). They also include a Pi2 with the brain, would be nice to get a pi3 now for the price.

Software wise, erle seems to be better packaged of you want to image and forget, but it doesn’t seem like you can load their software on any custom builds, so it means having to use their image as a base. The navio2 would be my choice for a pi2/3 since I want to add a flight controller to my Pi3 that already has a dev system on it and all my code. Erle wins for those that don’t want to mess with the command line. Documentation wise navio2 website is better more streamlined and clear steps on how everything is setup, erle seems harder to get the info you need, having to dig through forums for the answer or having to reverse engineer the scripts.

Kinda disappointed on all versions since I was assuming that the board would handle the processing and flight control where the pi would be a secondary processor, not primary. Downside is if you do want to run code on the pi, you have a chance of crashing if it bogs down or hangs the processor.

Weight wise the pxfminis is around 40grams loaded, the navio2 and erle brain2 is about 110grams each(with rpi3 and rpi2 respectively), with the navio being lighter all in once you account for the gps that the brain2 requires.

Honestly, Best setup for a true maker that wants a reliable FC and companion would be a pix hawk mini/light clone, one with a faster F4 processor and having an edison or pi zero as a secondary for size or pi3 or odroid for power. I have a Nvidia TX1 which is the ultimate companion compute device but there isn’t a lot of options for boards that would be small enough to actually use in practice. Shame on Nvidia for not releasing a smaller carrier board like the edison does.

I’ll post a better review of the software when I get them in the air.


#5

Last Christmas I bought an Erle drone that comes powered with the Erlebrain2 and I’ve had all kinds of problems getting it to work, no GPS lock and camera never worked, the response from the tech service at Erle was that they had a problem with the master made by DIY Drones and they would fix it and send me a new firmware to install, that was Feb 18th and when I got in touch with them just today, to ask for a solution to this matter, they blew me off sending me to their forum to wait for their engineers to find time off to post a response to me (those were Victors exact words printed on the email).
I recomend to stay away from any Erle made material since they do not stand behind their product.


#6

Sorry to hear about that, I know the guys at Erle are super busy and dont mean to upset their customers and probably just forgot to get back to you in all the madness, perhaps @vmayoral can help you out with this issue and help to get your autopilot working properly again so you dont need to use your erle as a paperweight!


#7

I don’t expect much from a company that lost its credibility in their last press release by stating they were in a project with DARPA when every body knows DARPA awardees must be American companies or nationals and ERLE is nor…
While at MIT, in DARPA projects when a foreigner came in there was a previous notice and all the manuals got closed and the research materials covered I don’t think after the incident with the Chinese chips with embeded backdoors things have got any easier.


#8

Hey everyone! New around here and I just bumped with this so i thought I’d share my 2 cents:

I’ve had several units of Erle-Brain 2 and a PXFmini and so far I’m delighted with all of them. I had an issue with Erle-Brain 2, notified the team and they replaced my unit immediately plus I’ve been getting decent good support at ERLE forum http://forum.erlerobotics.com in a pretty fast manner.

@Manny_Tolivia, are you aware of this resource? It seems that you should go over there instead of trolling around. As far as I can tell, tech support is all you need right?.


#9

Thanks @Jack_James for supporting us!
@unmannedtech1 also appreciate your wording.

As pointed out, support is given at our forum. Do not hesitate to reach us out there if there’s something we can help with.


#10

I’m not trolling, I’m using this resource to prevent others from making the same mistake I made And to Victor maybe I should post your response in which you blow me off and state that I would get tech support when ever your ingeneers have nothing else to do.


#11

Erle not have a free image for Raspberry.
navio2 yes have a free image for Raspberry.


#12

Hi Folks I have been researching my options for my first drone either build it from scratch with navio2 or Erle or a mixture of cheaper indvidual parts Flight controller ESC’s power distribution board rf rec and trans but im a total noob and not even flown a drone yet im waiting for Ethos Phone drone toarrive as that should also be an interesting toy with its 4g lte telemetry.

i really dont know much at all about making a drone let alone flying one specially when ive already paid out for Ethos im kind of stupid to buy another one for lessons aor is it risky flying a higher priced drone as oppsed to a cheap one to get the grips of?

PhoneDrone Ethos - A whole new dimension for your smartphone

Im also looking at windows 10 iot with rasperry pi
A cool drone controlled by a raspberry pi, a windows 10 device and an xbox one controller.

or just buying a PXFmini as i have a Pi 3 B and learning how to use it and add a few extra parts needed or forget these boards and go strictly with specific flight controllers but if i was to do so how would i go about achieving lte 4g is my real desire?

well anyway any advice is appreaciated.

also i found this link to Erle’s Git hub if you all wanted to get your free Erle OS/firmware?