toy rc helicopter pcm remote

On Sep 23, 7:51=A0pm, snipped-for-privacy@netzero.com wrote: >

>

Maybe it is but what exactly does it buy you? I also doubt the position detector on the servo is more elaborate than a pot as anything else costs too much. That means you're more or less back to the monostable whether you do it with a plain old MMV or convert your pot to PCM and compare numbers. Functionally it's the same thing. I submit that the PCM version may be less reliable than simple pulse widths as it requires more bandwidth in the TX / RX chain with greater possibility of errors. You did say it goes stupid which is how this thread started, right?

G=B2

Nothing. I just find your condescending attitude irksome. You're a dickhole, basically. You know nothing, yet you spout off anyways. You could have asked for a screen shot, instead you chose the path of the dick.

I was simply looking for help. *Someone* designed this, RC helicopters are not uncommon. You see the other people who replied? They helped. You didn't. You just wanted to hear yourself pontificate about what you doubt *I* saw. Idiot.

THERE ARE NO SERVOS YOU ILLITERATE BUFFOON. How many times do I need to REPEAT THAT!? IT'S AN ELECTRIC TOY HELICOPTER WITH DUAL ROTORS. So "doubt" away!

How old are you? Perhaps you are senile? Let me repeat again:

THERE ARE NO SERVOS INSIDE THE TOY HELICOPTER

Go grab your bifocals and your giant plastic Fresnel lens and take a look at this:

See any servos?

And when did I ever ask for help about non-existent servos anyways?

Good christ but you're tiresome with that. You're like a broken record. The things you have seen in your no doubt very long life are not the sum total of human experience. Monostable? What is this, 1973? It's either a toy ASIC or a microcontroller.

*There are no servos inside the helicopter.* Ugh.

There are two large brushed DC motors driven by some high frequency PWM drive and some 100A transistors. The unmarked microcontroller/ASIC inside the toy just varies the PWM to each motor which varies the torque/thrust the contra-rotating rotors deliver.

*****There is NO SWASHPLATE and NO VARIABLE PITCH TAIL ROTOR.*****

The tail rotor thrusts UP AND DOWN to tilt to helicopter forwards and backwards. It's a TOY. No FREAKING SERVOS.

All I know is the throttle has dead zones in it. I defy you to troubleshoot that with 18" rotors whirling away.

I wanted to find out more before I take the entire thing apart. Get it now? That's what I was looking to "buy", you fool, WHERE TO START. Knowing what the hell those pulses mean seemed like a good start to me. Perhaps you "doubt" that as well?

But all the other helicopters work fine with this "less reliable" method, dill weed. God you're such an arrogant little dick. You know NOTHING of the subject, yet veer off into chin-stroking comments. You're a professor, right? Some tenured moron who hasn't been challenged in decades? Am I supposed to tremble in fear at your every comment and re-write my reality to fit in your narrow world-view?

Please feel free to tell us how this method is "less reliable".

Have you seen a recent "hobby" grade helicopter remote? Want to pontificate while chin-stroking about those?

You know nothing, you are useless, you contribute nothing. You refuse to read, you refuse to learn, you refuse to help.

So, show me the servos or shut the hell up. I "doubt" you'll find them.

What is it that makes the tail rotor tip up and down?

At my first (ever) look at this post, I'd guess those two "motors" are actually "servos"... they look about the right size.

But the picture is an incomplete description. How about multiple _complete_ views? Full and close-ups.

Ascertain which "motors" drive the main and tail rotors. Then report back.

Hostility will only get your ass kicked :-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

                    Obama, All Blow but NO Hard

Oh Jim, now I know I'm being trolled. You definitely know better. However, because you asked...

Let's agree on definitions first, ok?

The word "servo" comes from the Latin "servus", which can mean "to watch over".

This implies two things.

1) There is feedback somewhere. In the hobby world, "servos" are little boxes with geared-down motors in them, and a means of sensing the angular position of some effector. Here's a picture of a servo from my RC nitro plane:

The arm moves in an arc of about 270 degrees IIRC. It has some torque to it but doesn't spin at hundreds of RPMs... Agreed?

You can also see the connecting cable with three wires. Ground, power, and feedback. There's three wires. Keep that in mind.

2) The servo mechanism itself doesn't provide power to move, lift or propel the aircraft. Rather, the servo *controls* the power source.

Here is a picture of my plane's nitro motor:

Would you agree that calling the motor a "servo" is wrong? Walk into a hobby shop and ask for a servo. No one will hand you a nitro motor, agreed? If you look carefully, you can see where the control rod attaches to the throttle. It's the white nylon bit (clevis) attached to the black arm. All it does is open or close the air valve. Fuel mix is a needle valve on the other side. Always fun to adjust...

OK, the entire fuel tank/motor/servo combination may be called a servomechanism, but the only part that is identified as a servo is ... well, the servo.

3) The servo is unable to spin 360 degrees. It has defined stop points. It describes an ARC.

A servo inside the plane controls a rod that opens or closes the throttle. The servo doesn't make the prop spin, agreed?

So a servo controls, has feedback, doesn't provide power, only turns in an arc. Yes?

OK, now take a look at this:

The same servo, the same stove, and a microcopter. Take a look at the thing, the microcopter couldn't even *lift* that servo. Instead, the microcopter uses small brushless DC motors to drive two gears that each drive one half of the coaxial rotor assembly.

Note that the motors:

1) Provide direct power to the rotors 2) Have no feedback, two wires.

(Also note the interesting LiPo battery in front. Cute huh?)

Here's a closeup of the microcopter's drive motors. You can just make out the two plastic gears:

So... Am I starting get my point across? Somewhere a chip takes in some PCM info about the controls and pumps out some PWM to the various motors. That's it. That's all. (In case you're wondering, the microcopter uses an infrared remote, which Glenn would probably "doubt" as well, even with three IR LEDs on the remote.)

Now, on to the tail rotors! Unlike conventional helicopters, these coaxial choppers use a fixed-pitch prop that can spin in both directions, but thrusting up and down instead of sideways:

Tiny, huh?

These coaxial choppers have several advantages.

1) Inherently stable, easier to control. 2) Simpler mechanical design, no swashplate. 3) To spin the helicopter entails varying the rotor drive power differentially. 4) Mechanically, there are only motors and gears, no complex push rods and swashplates. The top rotor *does* have a balance bar (called the "gyro") with push rods, but they are passive and very simple. 5) Light, powerful LiPo batteries and tiny DC motors enable toys even smaller than my microcopter.

The disadvantages are:

1) Much less control than a real helicopter. You can't fly sideways since there's no cyclic control. You have to turn the entire chopper then move it.

2) Tendency to generate lift out of the smallest breeze. Let's just say I've been on the roof a lot lately!

So here's the picture of the big guy that doesn't work. It's the same design.

And I can't get much clearer than this:

Two big gears driving the rotors, two metal gears coming from those large motors. Why yes the metal frame is buckled, that happened when it fell out of the sky from about 30 feet.

And the big guy's tail rotor.

Hmm, a DC motor, a gear and a fixed pitch prop that thrusts up and down. Note this tail rotor is the same diameter as the microcopters main rotors.

I'm tired of this. There are no servos and the remote is PCM (which is MORE RELIABLE, unlike what Goondlach preaches).

Am I becoming the Phil Allison of RC toys? Let's just say I understand him more and more lately. Some people in here shouldn't be allowed access to the net.

Anyways, in case I've piqued your interest, the microcopter is almost indestructible and probably for sale in every toy/hobby shop in the world. I've ordered a few on eBay where they are half-price but the shipping times from Hong Kong are 3-4 weeks.

Search for Syma S107 but be careful; they're addictive!

And this concludes this week's episode of a7yvm blowing his stack. Hope you enjoyed it, stay tuned for next week's episode!

With only rotors, something has to be able to "tilt" to effect control/direction/up/down, etc.

Something's missing here. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

                    Obama, All Blow but NO Hard

On a sunny day (Sun, 26 Sep 2010 12:23:17 -0700) it happened Jim Thompson wrote in :

You brain. At least you could have typed it in google and find it is a three channel, where the horizontal tail rotor tilts it forward or backward, and the difference between the coaxial rotor speeds sets direction. There IS no servo, and this was all in the OPs original post. makes me think if you EVER designed a controller for a plane. The thing has real gyro too, so I easy to fly. The digital control claims 32 steps for the motor speeds. So that is just PWM, but could be could be as simple as the presence / absence of one of 5 pulses in the control frame, simple binary code? Should be easy to test, one pulse should change most frequent when changing level. But they do mention some RF codes... A, B?? dunno. Look it up. I know a lot about it already after 5 minutes google, you find them at

it is easy to use even for a republican, well OK, maybe not.

Sigh.

There is no cyclic control.

You TILT THE ENTIRE CHOPPER WITH THE TAIL ROTOR. There's your forward/ backwards.

You vary the RPM of ONE of the motors to change directions. NO TILTING OF ANYTHING REQUIRED.

You vary the RPM of BOTH motors to change the thrust. NO TILTING OF ANYTHING REQUIRED.

That's it. That's all.

Facepalm. I explained everything. It's simple, it's obvious, it's all there.

Why are you guys all picking away at easily explained stuff but ignoring the PCM part? That's all I want to know about. I've set up the logic analyzer but this is going to be boring.

I'm going to wire the PCM signal from the remote directly to the receiver PCB with some wire and see what that does.

If you're so smart, why do you bother to ask? Your explanation of all the mechanisms involved is quite a bit less than lucid. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

    Parents are the bones on which children cut their teeth :-)

I'm speechless.

I guess the only way to solve this is by sending you one to play with.

,

They call it a 3.5, for the trim, but it sends out the trim as a seperate bunch of pulses, so logically it's a 4 channel remote but since the trim affects the same thing as the main stick I guess it's a "half" channel.

THANK YOU. It astounds me to see how baffled people are by this toy. No servos. PCM remote.

I *am* surprised to see what difficulty he's having with this... I'm utterly speechless. He's an electrical engineer? Usually software types are the ones completely disconnected from physical reality.

sence of one of 5 pulses

Well, for my large chopper the number of pulses is always the same but the width changes. More like the duty cycle. A 50% pulse seems to be a

0, and a 33% high pulse seems to be a 1.

ng level.

Oh it is, but the problem with the big guy is the random cutting out of the throttle, which has nothing to do with servos or swashplates, but some people just don't get it. I don't have a problem witht he mechanics. It's the electronics. That's why I asked in here.

It's not one pulse. It's more complex than I expected, and obviously too complex for some people in here.

I just don't have the PLACE to start taking apart such a large helicopter and all I wanted was some help decoding the PCM format.

I've stopped working in electronics a long time ago and don't have the lab I used to. I have various tools but no freaking space.

The microcopter uses an IR remote with three codes, A, B and C. The chopper has a sticker under it telling you what channel it's on. You can use the same remote for different choppers.

.google.comit is easy

No kidding. I can't understand the problem people are having here. How do they drive a car?

LOL I don't know....

I just don't know what to say or do anymore. It's kind of funny in a way.

I really just wanted to know about PCM encoding in toy remotes. Guess it's such a complex, arcane subject requiring decades of peak training and strict exams. I'll never find out. It's too complex for me.

To be fair, I never found waveforms for today's hobby remotes either. It's a weird hole in global knowledge. It's a closely guarded secret handed down from one generation of remote makers to the next.

I'm off to do the dishes. And put my servo back where it came from.

Hmm, I also think it has a servo. Can you send me one to play with? :)

M

I once landed a contract to actually generate servo control signals for a household robot that this guy was trying to market - the user needed a joystick; my client had just heard of "Butler in a Box" and wanted voice control for his robot. He had used Futaba servos, with the xmtr at the wheelchair.

So, I actually made an appointment with the local Futaba tech, and he spilled his guts, since I'm also a tech - I was only playing design engineer. ;-)

The scheme was quite simple - analog PWM.

But it certainly could do no harm to call, email, or write whoever makes your servos and ask nicely if they'd be so kind as to share their PWM or PCM or whatever modulation scheme - especially if you make it sound like it's another marketing opportunity for them. ;-)

Good Luck! Rich

Are all neocons so dense? Of course, it's silly to ask. Of COURSE they're dense, that's why they're neocons.

I have a perfect picture of what a7 is saying, and get the impression that he wants to control his servos with something besides the stock remote; he's only asking if anybody knows their PWM code.

Of course, if that's not accurate, I'd much prefer to be enlightened.

And the logical people to ask are the makers of the servos in question.

Unless I've also missed something.

Thanksk, Rich

It definitely has servos. And I am a republican. Please send me two. :)

tm

On a sunny day (Sun, 26 Sep 2010 19:40:19 -0400) it happened "tm" wrote in :

I am not a republican, and I think this way: Many times I thought of buying one of those little copters. But what to do with it? There are the big 4 rotor ones, they come with camera, maybe make some money with aerial photography, security. Those have limited flight time anyways. A better thing would be a big glider with electro motor, it could stay up there for many hours. But what is the use, except obstructing air traffic? No, I would like a really big one, like Hawkins described in his TV series, space ship, that accelerates at 1G, and, after many years, reaches almost the speed of light, In 80 years reach a star, now I would like one of those, while you are giving.

On a sunny day (Sun, 26 Sep 2010 13:42:13 -0700 (PDT)) it happened snipped-for-privacy@netzero.com wrote in :

Been thinking about that RC IR code. It could just be a simple SDLC or HDLC frame, sync byte, some data bytes, address, address, address (A,B,C), channel1, channel2, channel3, and CRC.

If you move a control the CRC byte, the last few bits, would always change. But also one or more bits before that in a channel field. Having CRC makes sense, as somehow in bad signal conditions, the chopper will have to check if the frame is valid. The coding could then be NRZ or such.

I played with that system in the past, a Z8530 (Z80 chip) can generate and decode that format.

But a safer bet would perhaps be to do some googling for RC IR helicopter codes etc.

Personally I would take out the little PCB, and say if there is a 5 bit data path between the IR decoder and the PWM generator, check for shorted tracks, and bad soldering. Also in your picture I see cut of wires...

channel2, channel3, and CRC.

e.

will have to check if the frame is valid.

d decode that format.

codes etc.

ata path between the IR decoder and the PWM generator,

Good eye. Those toy choppers come festooned with dozens of flashing LEDS which I find annoying. (I've decided to call them Goondlach Lights.) I remove them and the wires. I kept the front white LEDS, they're cool. The light show strips on the back are useless to me, but there's a white light under the tail rotor which I kept.

snipped-for-privacy@m15g2000yqm.googlegroups.com...

Syma S107 on eBay! Pick and choose the best deal. Wait three weeks for shipping. Enjoy! (And note the utter and complete absence of servos)