Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Raspberry Pi inspired autopilot

emlid.com

Post reply on HN
Print view View original

51–60 of 61 posts

Re: Raspberry Pi inspired autopilot

#51

Post by georgemcbay »

igorvereninov wrote: post #16
mjs7231 wrote: post #13

Just curious here. The CC3D boards were also open source, hackable, and only 1/3 the price, and guessing, but looks about 1/5th the size. What makes using better than all those downfalls?

This is completely different. Autopilot runs under Linux and that gives incredible flexibility. You can send HD video over LTE, run scripts in flight. SSH to drone in the air, how cool is that?

Not sure how different it really is.

I have to admit, as someone who is into quads (and embedded software) my first thought was that it would be cheaper to buy a $35-60 CC3D or knock-off dedicated APM module and then just add a Raspberry Pi to the quad as a separate unit. Having the two communicate is a bit more complicated but totally doable via serial if you're willing to hack on APM or OpenPilot code and a lot of the use-cases people are bandying about don't actually need the two units to communicate anyway.

Re: Raspberry Pi inspired autopilot

#52

Post by scoot »

mavkhimenia wrote: post #41
tomswartz07 wrote: post #19

This is very neat! Has there been any thought about using the 'Compute Model' RasPi? It's the RasPi in the DIMM form factor. Perhaps this would help lighten up the payload even more?

Thanks! We've been thinking of it, but rejected the idea. RPi A+ is quite light, so RPi+Navio weighs as the normal autopilot. Also, A+ is much cheaper.

> RPi A+ is quite light, so RPi+Navio weighs as the normal autopilot

Not to detract from the novelty value of an RPi based flight controller, but if you were involved in the design, you must know that's just not true:

RPi A+: 23g, Navio: 24g, Total: 47g

APM Mini: 7g

That's a significant difference in a situation where every gram counts towards flight time.

The Navio also costs 6X an APM mini, and that's before you add the RPi and power module, which brings it to 8X.

I get why someone might develop this as a hobby project, but I can't think why anyone would buy one.

Re: Raspberry Pi inspired autopilot

#53

Post by 2bluesc »

MegaDeKay wrote: post #33
Jeandon wrote: post #2

Looks very nice. Is Linux actually real-time enough to run autopilot code?

The second PDF in the link below compares the Raspberry Pi with the Beaglebone Black for a next gen APM. The nod went the the Beaglebone because of more GPIO, PWM support, and the two PRUs for realtime operation. The Pi B+ helps the first point, but not the other two. There is also a really interesting page in here on the latencies that are required. BTW, this was written by Andrew Tridgell of Samba fame. http://diyd…

Thanks for this. Whenever I see people running around high fiving over the Raspberry Pi, I start to formulate an argument how the BBB would almost always be vastly superior for slightly more cost.

Re: Raspberry Pi inspired autopilot

#54

Post by mavkhimenia »

scoot wrote: post #52
mavkhimenia wrote: post #41

Earlier quoted context omitted.

Thanks! We've been thinking of it, but rejected the idea. RPi A+ is quite light, so RPi+Navio weighs as the normal autopilot. Also, A+ is much cheaper.

> RPi A+ is quite light, so RPi+Navio weighs as the normal autopilot Not to detract from the novelty value of an RPi based flight controller, but if you were involved in the design, you must know that's just not true: RPi A+: 23g, Navio: 24g, Total: 47g APM Mini: 7g That's a significant difference in a situation where every gram counts towards flight time. The Navio also costs 6X an APM mini, and that's before you ad…

Navio does NOT weight 24g. It's weight is around ~12g. RPi A+ with Navio = 23+10 = ~35g. Pixhawk weights 38g.

With Navio+RPi you get a lot of stuff compared to hardware like APMMini: network connectivity (LTE, long-range WiFi), affordable 1080p camera module with H.264 encoder for FPV, a lot of processing power for advanced flight algorithms (as an example - a lot of new features of APM such as EKF are NOT available on old APM platforms) and the overall hackability, which you don't get with any microcontroller based autopilot.

Re: Raspberry Pi inspired autopilot

#55

Post by mavkhimenia »

Phlarp wrote: post #48
zo1 wrote: post #32

Earlier quoted context omitted.

Why would there be large delay? Am I missing something that you'd care to fill us in on?

Most hobbyist multi-rotor flyers use an analog video feed over 1.2ghz or 5.8ghz radio, which has very minimal lag. Converting the video to a digital signal typically introduces 500-1000ms of delay, which is enough to make flying by the camera difficult or nearly impossible. Transmitting the signal over an IP switched network would likely introduce more lag in addition to the digital conversion. Ultimately it will dep…

The delay with Raspberry Pi camera module and proper LTE\WiFi link is much less - it's around 100ms.

Re: Raspberry Pi inspired autopilot

#56

Post by mavkhimenia »

georgemcbay wrote: post #51
igorvereninov wrote: post #16

Earlier quoted context omitted.

This is completely different. Autopilot runs under Linux and that gives incredible flexibility. You can send HD video over LTE, run scripts in flight. SSH to drone in the air, how cool is that?

Not sure how different it really is. I have to admit, as someone who is into quads (and embedded software) my first thought was that it would be cheaper to buy a $35-60 CC3D or knock-off dedicated APM module and then just add a Raspberry Pi to the quad as a separate unit. Having the two communicate is a bit more complicated but totally doable via serial if you're willing to hack on APM or OpenPilot code and a lot of…

Each approach has it's advantages. Navio was built to serve as a Linux platform for APM which provides more processing power than microcontroller platforms - it's useful for advanced flight algorithms (for example, a lot of new features of APM asuch as EKF are not supported on older APM hardware) and the level of integration between payload apps can be much higher than on two modules with serial link.

Re: Raspberry Pi inspired autopilot

#57

Post by mavkhimenia »

eots wrote: post #47
igorvereninov wrote: post #16

Earlier quoted context omitted.

This is completely different. Autopilot runs under Linux and that gives incredible flexibility. You can send HD video over LTE, run scripts in flight. SSH to drone in the air, how cool is that?

Yes, SSH-ing to my drone and running scripts while doing low passes and tight turns is just what I need. Sarcasm aside, this looks really cool from a hacker perspective but I'm straining to find a practical use case. Both CC3D and Naze32 platforms are open (hardware and software), smaller in size, cost 5 times less -- but are, I guess, nowhere near as flexible as this thing.

Well, SSHing may be not that useful for those who just want to fly a drone, but it's quite useful for developers, researchers and enthusiasts. Compared platforms are way less powerful and won't be able to perform new advanced flight algorithms, as well as they do not provide easy network connectivity for 1080p H264 video stream from Raspberry Pi's camera module.

Re: Raspberry Pi inspired autopilot

#58

Post by mavkhimenia »

2bluesc wrote: post #53
MegaDeKay wrote: post #33

Earlier quoted context omitted.

The second PDF in the link below compares the Raspberry Pi with the Beaglebone Black for a next gen APM. The nod went the the Beaglebone because of more GPIO, PWM support, and the two PRUs for realtime operation. The Pi B+ helps the first point, but not the other two. There is also a really interesting page in here on the latencies that are required. BTW, this was written by Andrew Tridgell of Samba fame. http://diyd…

Thanks for this. Whenever I see people running around high fiving over the Raspberry Pi, I start to formulate an argument how the BBB would almost always be vastly superior for slightly more cost.

There a lot of boards that outperform BBB 10-20-30x times. But both RPi and BBB are more than enough to run an autopilot code. One of the great advantages of RPi over BBB is 1080p camera module with hardware H264 encoder as well as bigger community.

Re: Raspberry Pi inspired autopilot

#59

Post by georgemcbay »

mavkhimenia wrote: post #56
georgemcbay wrote: post #51

Earlier quoted context omitted.

Not sure how different it really is. I have to admit, as someone who is into quads (and embedded software) my first thought was that it would be cheaper to buy a $35-60 CC3D or knock-off dedicated APM module and then just add a Raspberry Pi to the quad as a separate unit. Having the two communicate is a bit more complicated but totally doable via serial if you're willing to hack on APM or OpenPilot code and a lot of…

Each approach has it's advantages. Navio was built to serve as a Linux platform for APM which provides more processing power than microcontroller platforms - it's useful for advanced flight algorithms (for example, a lot of new features of APM asuch as EKF are not supported on older APM hardware) and the level of integration between payload apps can be much higher than on two modules with serial link.

Yeah this is a good point, if you are tightly integrating the linux bit to the flight controller bit you will get some benefits here, I was focusing primarily on the topics other people keep mentioning like compressed video feeds which don't require that sort of integration.

It is certainly an interesting project, though personally I'd be more apt to buy/build a BeagleBone Black cape to achieve this sort of thing over a Raspberry Pi board.

Re: Raspberry Pi inspired autopilot

#60

Post by lacksconfidence »

mavkhimenia wrote: post #55
Phlarp wrote: post #48

Earlier quoted context omitted.

Most hobbyist multi-rotor flyers use an analog video feed over 1.2ghz or 5.8ghz radio, which has very minimal lag. Converting the video to a digital signal typically introduces 500-1000ms of delay, which is enough to make flying by the camera difficult or nearly impossible. Transmitting the signal over an IP switched network would likely introduce more lag in addition to the digital conversion. Ultimately it will dep…

The delay with Raspberry Pi camera module and proper LTE\WiFi link is much less - it's around 100ms.

Do you all have any plans to shave that further? What might be considered the ideal maximum latency for things like flying obstacle courses(fpv racing)? landing from fpv?
Post reply on HN