World's Smallest Homebrew RC Unit

MC68040 writes "I assume you've seen the mini-helicopters and airplanes that are becoming increasingly popular as office toys out there. Well this guy decided the market wasn't filled enough, luckily =) He's built the by far simplest and most functional mini Remote Controlled unit. It weighs under 7 grams, is made of carbon fiber and it's smaller than your thumb (or a hamster, as the author seems to prefer to compare). Go check it, it's truly a amazing feat."

Comments

Want to buy one?

[zeux]

From this page:
Pixels are unique prototypes, and are not for sale. I am sorry for all those who would like to buy one.

Too bad I can't buy one... Do you know if it's possible to buy an equivalent or to build my own? Is it a hard work?

Looking at the pictures it doesn't seem hard to do...

Neat-O! No swashplate!

[GMontag]

So, how many hamster units equal a Library of Congress?

Neat that he eliminated the swashplate, but he is a bit mysterious about the details:

Back in 2000, I started playing with the idea of eliminating swashplate, servos, pushrods and so on. I was actually successful in realizing this.

A patent was filed early 2001. The 'problem' is that soon after that, a company took a license on this technology, and required to keep confidentiality. This implies I can not show pictures, or give details or comments about the way this works. I even had to edit some of the pictures on this site to make sure this was respected. And off course there is a money side to it. I hope you understand.

Interesting development though. It certainly cuts down on the weight and complexity. Wondering if it is workable in full-size aircraft? Well, that is an assumption that it is not a variant on the "Rigid Rotor" system that the Cheyenne AH-56A and other aircraft used.

More history of Army aircraft here

Re:Neat-O! No swashplate!

[Cid Highwind]

A patent was filed early 2001. The 'problem' is that soon after that, a company took a license on this technology, and required to keep confidentiality. This implies I can not show pictures, or give details or comments about the way this works. I even had to edit some of the pictures on this site to make sure this was respected. And off course there is a money side to it. I hope you understand.

Ummm, the whole *point* of a patent is that it protects your implementation, but makes the underlying theory available to anyone who wants to know. Part of the patent process is disclosing how your invention works.

Who is this unnamed company, and why do they get to demand this secrecy that is contrary to what a patent was meant to accomplish in the first place? IM(NS)HO, a stunt like this should be grounds for throwing out a patent.

Re:Neat-O! No swashplate!

[Anonymous Coward]

he doesn't use servos but magnetic actuators, PicoBird from Didel: "The the 6.9 grams Pixelito. built by Alexander van de Rostyne uses DIDEL motor, gears, PicoBird and IR control (TedRa and Mim4)."

--
Croco

Re:Neat-O! No swashplate!

[Crypto Gnome]

A patent was filed early 2001. The 'problem' is that soon after that, a company took a license on this technology, and required to keep confidentiality. This implies I can not show pictures, or give details or comments about the way this works. I even had to edit some of the pictures on this site to make sure this was respected. And off course there is a money side to it. I hope you understand.

You licensed your patent to a company and allowed them to include draconian exclusivity clauses?

All I can say is I sure hope you are now *really friendly* with your bankers in Switzerland otherwise you got *badly screwed*.

Re:Neat-O! No swashplate!

[GMontag]

There was something like that in the old (1985-era) Army Aviation Museum at Ft. Rucker, AL. The aircraft was much older. Concept did not go past the flyable prototype stage IIRC. Was essentually a fully-articulated rotorhead with servos and a multi-connector disk/brush system.

Even if this new concept is exactly the same thing that certainly would not stop some patent offices from granting a patent anyway (as we have seen reported by /. numerous times).

Flight issues at small scale?

[Lord_Dweomer]

So I know when you scale helicopters down they get much harder to control, which is why RC helis tend to be so damned jumpy compared to their full size brethren.

Could anybody who knows the physics behind this please explain how this thing will perform/behave compared to a normal RC heli, and then compared to a full size heli?

Re:Flight issues at small scale?

[LiquidCoooled]

isnt it to do with the range of motion the servos have than the full sized control units?

TO miniturise them you can only get a preset range of positions.

I am only speculating, but it seems plausable after the mini RC cars I have owned, my original large 1/12 scale had variable steering, but the smaller ones all seem to operate simply between straight ahead and full lock.

Re:Flight issues at small scale?

[Anonymous Coward]

It's all weight and momentum.

Just like a huge ship takes a long time to turn, the larger/heavier flyers are more stable (especially outside).

With gyros the small ones can be very stable when there is no wind.

Re:Flight issues at small scale?

[c4Ff3In3 4ddiC]

Actually, you just have to quit buying toys. For example, I recently picked up a 1/18 scale Losi Mini-T. It's just a smaller version of their 1/10 scale truck. Fully proportional stearing, electronic speed control, etc. Mine will go about 20MPH (No, it's not stock).

Re:Flight issues at small scale?

[jd_esguerra]

Not-too-technical speculation ahead:

A few points: First, a craft with small inertias would be susceptible to random environmental disturbances: It would get blown around in turbulence. Second, in the case of sensor/electrical noise, the lower inertia of an RC craft would allow the actuating mechanisms to impart a noticable mechanical response to higher frequency noise (F=ma, T=I(dw/dt)). And C, the huge mass of the control surface components of the full-sized helicoptor would not allow their servo control loops to be operated at so high a bandwidth. An analogous situation would be the power steering mechanism of a car vs the steering mechanism of a RC car. (How fast can you alternate between 45-degrees right and 45-degrees left with the RC car ? With the real car ?)

These args also apply to the system response to operator input. A twitchy finger on the RC control will send a twitchy reference signal to the servos on in the RC vehicle. The high-bandwidth servos will move track the "twitchy" reference signal, moving the control surfaces. Being not-so-massive, the RC heli will respond (accelerate) quickly to the change in forces/torques created by those surfaces. A "twitchy" operator in a real heli might impart an equally "twitchy" reference signal to the heli's servos, however, a combination of large-mass, actuator/control system limitations, and mechanical limitations will cause the "twitchy" part of the signal to be low-pass-filtered.

In a calm operating environment with undisturbed air, a RC heli could probably be made to operate like a full size heli by lowpass filtering the commands to the actuators controlling the control surfaces.

Re:Flight issues at small scale?

[deblassc]

Its all about Mass.

a full scale (real) heli in a hover is easier to control due to the mass of the aircraft. wind and turbulance have much less effect on it and the craft as a whole reacts "slower".

when you get down to the .60 size choppers slight winds and such that wouldnt be even felt with a full scale start to buffet the chopper requiring more input . it also reacts quicker then the fullscale due to less mass being thrown around.

when you get to something like the pixel sized... a small fan can be catostrophic.

same with airplanes. a 1/2A scale plane (.049 sized engine) is a whole lot harder to fly then a 40% giant.... but a lot cheaper.

Re:New solutions create new problems...

[Moderation abuser]

You put a camera on board.

http://www.rc-cam.com/

Other things you can do with RC helicopters

[Realistic_Dragon]

One of the research groups here has a RC helicopter that has mounted on the bottom a video camera, a still camera, location system and 4 FM 56kbps transmitters. It has an embedded xscale and embedded PPC processors.

It's supposed to be a testbed for data compression and transmission type stuff, but in fact they mostly use it on hot summer days to look in local gardens for sunbathing women :)

This looks like a nice project..

[Awptimus Prime]

I would like to see someone post some mini-RC howto sites. Some instructions on how to build a little chopper or plane would be some nice reading.

Re:This looks like a nice project..

[Awptimus Prime]

Okay, I am not one to usually reply to my own comment, but I went searching for small-scale projects and found a design involving using parts from a $10-40 TOMYTEC mini-RC car (or clone) and a $13 electric airplane.

It involves a decent amount of hardware hacking, but looks like a fun design for not much money. Mind you, you can probably buy a pre-built toy with similar capabilities for about the same money.

The project is located here.

he should really

[Digitus1337]

He should really attach a little beeper thing to it. Like a car in a parking lot, this thing could be lost very easily.

email

[nycsubway]

I was getting dozens of junk emails about the "new mini RC cars! the smallest RC car available" around christmas time last year. I wonder if he had anything to do with those emails....... hmmmm.....

Bending carbon rods

[vikstar]

I'd like to try my hand at one of these. You can easily buy straight carbon rods at a hobby shop, but does anyone know of a away to bend them into a desired shape, like the helicopter chassis in pixelito?

looks like it uses a piezo controller

[nietsch]

instead of a swashplate, it uses one piezo contoller that adjusts the angle of the rotor blades (tilt is longitudonally (sp?)) The peizo element is driven by the current running between two contact pairs.
1 for forward/reverse 1 for sideways.

(now for some -i know it better than this guy- ramblings:
It could be done even simpler with a little more logic in the controller: eliminate the divided pickup ring and replace it with two continous contacts on the rotorshaft. determine the rotor speed from a optocoupler or the motor, and have your controller output the right pulses at the right time. More electronics, less moving pairs. better control over the rotor angle at all parts of the cycle)