DIY Drones: Home for everything about amateur Unmanned Aerial Vehicles | Hacker News Reader

DIY Drones: Home for everything about amateur Unmanned Aerial Vehicles

diydrones.com

Although not a drone, it is pretty cool to see this tech being open sourced, getting miniaturized, and at a price point where many people can afford them. Take the Crazyflie Nano Quadcopter [1] for example, open source and fairly cheap, there is even a really cool demo video [2], I guess you could use the DIY drone software on your laptop to control this thing. I generally think of open source as software, but it's very cool to see hardware project too, there are even wikis for the copter [3] and radio [4], which explain the projects and the hacks. To help get a sense for how small this thing is check out this assembly video [5].

[1] http://www.seeedstudio.com/depot/crazyflie-nano-quadcopter-k...

[2] http://www.youtube.com/watch?v=3WBUVYZkODI

[3] http://wiki.bitcraze.se/projects:crazyflie:index

[4] http://wiki.bitcraze.se/projects:crazyradio:index

[5] http://www.youtube.com/watch?v=kS3qR1IjeGE

You can't use the "DIY Drone" (really Ardupilot) software to control Crazyflie until Crazyflie supports the MAVLink communication protocol.

To add some context, this page is run by Chris Anderson, formerly editor at Wired, and now CEO of 3D Robotics. His book "Makers" [1] includes a few stories about the DIY Drones community.

[1] http://www.amazon.com/Makers-The-New-Industrial-Revolution/d...

Also, this is basically a forum + storefront for his internally developed drone kits. I find his Optical flow sensor the most interesting of these.

I met him once when he gave a presentation at my employer. He is quite aware of the defense and security repercussions of this technology, but he didn't really want to discuss it. My impression is that he sees himself as a military consultant, long-term.

The Optical flow sensor is not his, it is: https://pixhawk.ethz.ch/px4/modules/px4flow

I say this, because the 3Drobotics/DIYdrones guy doesn't go out of his way to make these distinctions.

These swiss guys have 3Drobotics/DIYdrones place the parts & sell their board because these guys have very aggressive marketing & a pick & place bot. This allows them to focus on the actual engineering.

3Drobotics/DIYdrones have a fork of the Swiss guys code with a generic interface plastered over the top. They are moving to this hardware, because "their" own hardware is out of date & no longer competitive with the current generation of STM32 hardware everyone now uses. They have a couple of employees who are capable of making this eventually approximate the original design.

He said his development team was working on a optical flow sensor and he showed us slides of his workshop. Perhaps they're selling a 3rd party until they can provide their own?

This is very interesting. A friend of mine is trying to make an Arduino quadcopter so he can learn the framework. It's already functional, but there's still some work to do like stabilization algorithms and GPS stuff.

Check out these guys at ETH Zurich. They have an open source quadrotor control package, though their main product is an optical flow sensor.

https://pixhawk.ethz.ch/

I would characterize their main efforts as building a modular autopilot software & hardware infrastructure, for which the optical flow sensor is one part. They are both an academic research group & generous providers of an open source platform competitive with the best out there.

Also check out Openpilot & Paparazzi--of which http://transition-robotics.com is a good current example.

Are all Drones so loud? Is there any possible way to make the quieter? Even silent? Looking through the videos and reading a bit it sounds like an issue is with the gears or motor producing the majority of the sound.

What kind of 'drones'? Tri-/Quad-/Hex-/Octa- etc copters are typically direct-drive, with unshrouded conventional propellors. You could certainly make them quieter by optimising the pop design, putting the props inside shrouds, etc.

Just using a bigger, slower spinning prop, on a bigger (so the props are further apart) chassis can go a long way, in terms of noise.

For an electric helicopter, most of the noise comes from the pressure waves coming off the tail blades interfering with the waves coming off the main rotors. Full size helicopters minimise this by switching to NOTAR and fenestron designs. Gear noise can be substantial on older designs of model helicopter, direct-drive is extremely rare, I think only Robbe ever made a direct drive design, cheap, strait cut gears are more common. Belt drive designs are available now though, and at low RPM, reasonable quiet.

If you're really concerned about noise though, you'd just build around a motor glider. So long as its not going so fast that the whole thing whistle's it'll be effectively silent.

I'm assuming you're referring to fixed-pitch hovering drones. There, most of the noise is made by the propellers. For reference, running a quadcopter at full blast with no props on is pretty quiet.

There are some optimizations you could theoretically do by moving to variable pitch, and trading off pitch for RPM (or the other way around, I don't fly helis myself)

Yes, sorry I should have been more specific.

After researching the blades a little further is seems a company called eurocopter did find a way to reduce the noise made by the propellers [1]. Heres a video of the difference between the two blade types [2]. Do you think this would be applicable to the blades at the drone level?

[1] http://www.wired.com/autopia/2010/02/eurocopter-moves-one-st... [2] http://www.youtube.com/watch?v=dBS1NRsYuF8

Helicopter propellers are typically even louder, since the tips are going supersonic (due to the diameter of the propellers). The trademark "chop chop chop" sounds, as far as I know, are caused by sonic booms. The tech you're linking to is about minimizing the source of sound for the sonic boom.

Airplane and drone props are entirely subsonic. They make a lot of noise when the pitch is significantly different than the speed that the airplane "should" going at. In other words: if you imagine a propeller cutting through butter, there is a certain distance it would go in one rotation. Propellers are loud when they're going significantly over or under that distance. Also - I'm just a hobbyist, so my explanation may not be correct.

This effect is especially noticeable with fixed-pitch propellers used for hovering.

For reference, check out these videos. Note that airplanes have 1D variable pitch.

[1] http://youtu.be/e8nYZ-fMSHg?t=1m5s - note the sound at 1m12s

[2] http://youtu.be/QB6vtE3rIrQ?t=9m15s - note the sounds at 9:25 and 9:53.

For more examples, see https://www.youtube.com/results?search_query=propeller+taxii...

This "community" while having been around for awhile is controlled by an autocratic self promoter who uses it to sell his stuff, & longs to sell out the community to the fullest extent of his abilities. Note the content of the main real estate of the front page versus the wider interest of the broader community.

For the higher quality stuff & open source in good faith goods, google PX4 ETH native (not the Ardupilot version ), Openpilot, & Paparazzi.

I'm thinking they should add a 'legal' page, where they can notify potential UAV pilots of laws they might break accidentally when flying these things. I'm sure there are a few regional restrictions in addition to any federal ones.

Would be better to have a Google Maps embed tagged with "Areas of Interest".

That'd probably motivate the legal page even more, though.

It is not a strictly US based community.

In the spirit of other hobbyists the DIYDrones community often laces their posts with warnings about heeding local laws. Larger projects are often based from airports so talk is had about regulations involved as well.

Aside from the individuals on the site asking others to research and listen to local laws/regulations articles on laws around RC craft and drones in various nations are also posted frequently.

It's been lovely seeing the community grow. Welcome all.

Legal page:

   http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A28583

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