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Old Apr 11, 2012, 03:36 PM
Micro Jet Pilot
Chris T's Avatar
Joined Jul 2005
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Originally Posted by jkarran View Post
Nintendo Wii handset?

This is really cool work Chris.
You got it i took the handle from a nice logitech joystick...
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Old Apr 11, 2012, 03:50 PM
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Hampton, VA
Joined Mar 2009
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Chris T,

Dude, you are strictly cutting edge! Been watching from afar. Will love to see this one fly.

Ksqm
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Old Apr 15, 2012, 12:13 PM
Micro Jet Pilot
Chris T's Avatar
Joined Jul 2005
2,080 Posts
Hi,

I am looking for a source of disc magnets for servos. D2mm x 1mm N50 magnetized through the length. Anybody knows where to get that?

Thanks

Chris
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Old Apr 15, 2012, 03:43 PM
Addicted to building...
Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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Quote:
Originally Posted by Chris T View Post
Hi,

I am looking for a source of disc magnets for servos. D2mm x 1mm N50 magnetized through the length. Anybody knows where to get that?

Thanks

Chris
Closest thing I know of, some of which I own, and have bought through this company: 1/16" dia, 1/32" thick, so guess its more like 1.5mm dia x .8mm. Link to magnets.
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Old Apr 18, 2012, 12:43 AM
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Oak Ridge, Tennessee
Joined Dec 2007
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How many disc magnets do you need? I've got some from here:
http://www.supermagnetman.net/produc...roducts_id=145
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Old Apr 18, 2012, 08:14 AM
Micro Jet Pilot
Chris T's Avatar
Joined Jul 2005
2,080 Posts
Damn, how come I didn't find these? I ordered a bunch of N48 ones here
http://magnetmonster.de/
They are not N50, but the difference should be small. Dan, I would love to get some more of the brass tubes for .5mm shafts you sent to me once. Would you tell me where I can buy these?

Thanks

Chris



Quote:
Originally Posted by shagrug View Post
How many disc magnets do you need? I've got some from here:
http://www.supermagnetman.net/produc...roducts_id=145
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Old Apr 18, 2012, 10:06 AM
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Oak Ridge, Tennessee
Joined Dec 2007
374 Posts
Not easy to find, only a few KS vendors carry this size:
K&S Round Tubing .006" 1/32" TT61

It comes in 12" lengths, usually 8 sticks per package. The ID is undersize so you will need to ream the bearings with a .020" bit. (.5mm for you)
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Old Apr 18, 2012, 12:27 PM
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Freddie B's Avatar
Omaha Nebraska
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Quote:
Originally Posted by shagrug View Post
Not easy to find, only a few KS vendors carry this size:
K&S Round Tubing .006" 1/32" TT61

It comes in 12" lengths, usually 8 sticks per package. The ID is undersize so you will need to ream the bearings with a .020" bit. (.5mm for you)
If you find a vendor, please share. I'd love to have some of that too!

Fred
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Old Apr 18, 2012, 02:46 PM
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United Kingdom, England, Surrey
Joined Aug 2002
834 Posts
Hi Chris and all,

Thanks for your help on the sensorless controller, I now have a working controller and have built a couple of motors. For speed control I centre the on period between two zero crossings (based on the interval between the last two zero crossings) and vary its width, max throttle being 70% on. So for example if the last interval was 100ms, at full throttle I switch on 15ms after the last ZC and off at 85ms, then wait for the next ZC.

Is this similar to what you do? I don't have a reliable startup yet, I have to flick the prop, any pointers?

Something I can't explain is the two motors i've built so far (4x8mm magnet, 0.2mm wire) one 40 and one 60 turns seem to show identical RPM at the same voltage? I was expecting the RPM to change, maybe I need to try thinner wire and more turns, coil resistance was <2ohms so maybe the KV in both motors was just too high for the prop I'm spinning (AA prop).

Cheers, Joe
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Old Apr 18, 2012, 10:27 PM
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mudville
Joined Nov 2002
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vendors for tubing...

http://www.amazon.com/Engineering-Ro.../dp/B0006NAT4I

http://www.hobbylinc.com/htm/k+s/k+s15035.htm


SteveH
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Old Apr 18, 2012, 10:29 PM
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Thanks SteveH. Very pricy but very hard to make too I imagine.

Fred
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Old May 01, 2012, 01:49 PM
pem
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Frankfurt Intl, Germany
Joined Feb 2004
290 Posts
for tubes look there as well:

http://www.hero-berlin.de/German/Pra...agerliste.html
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Old May 02, 2012, 02:12 AM
Micro Jet Pilot
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Joined Jul 2005
2,080 Posts
Hey guys,

here is an update: I finished a prototype of my all new wii type tx. I wanted to show a photo of that good looking piece right here. I still can do but I have to report that I am a lot less enthusiastic about it now I got it to work well, I even resolved my range problem by introducing a printed circuit bifa antenna, so I shouldn't have those motor dropouts anymore, which the big squall showed from time to time. Now comes the problem. I figured how important a reproducible neutral position of the controller is. On a stick tx, I first perfectly trim the model and then control the plane by short stick movements and letting the stick return to its neutral position. This way I know exactly, when the model is going straight. With the wii type controller you don't have a reproducible neutral control. You kind of have to feel where the orientation of the controller is that corresponds to neutral and every tiny deviation will make the model roll, climb or dive. I tested with the 6'' squall to have a comparison. I managed to handle it in the end and did a full circle. Then with full speed I went over my head and through the sun, while turning my body and the tx to the other side. Here comes the other problem. That movement causing centrifugal forces looks to the controller like elevator down. I knew that already and intended to make a compensating up movement. But by the time the model came out of the sun, It was diving in with full speed and 70000rpm. I have done about 50 launches with that controller and abused the 6'' so much that I came to the conclusion that that type of control will never give the authority and precision we are used from a stick. Too bad, but that seems to be the fact.

The motor mount of the squall came loose when it knocked in and the running rotor broke. That's it. The fuse is fine. Incredible. Now I might improve the motor setup, since it is already out

I will continue on the 3'' model as soon as this is fixed. At least I know that I shouldn't put a lot of effort into the tx

Chris
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Last edited by Chris T; May 08, 2012 at 07:05 AM.
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Old May 29, 2012, 05:10 AM
Micro Jet Pilot
Chris T's Avatar
Joined Jul 2005
2,080 Posts
Update:

Hi,

I have been buzy optimizing my servo code lately. I didn't want to hear that noise any more the servos made. So I introduced a 30kHz pwm and PI-control. Now you have to go really close with the ear to be able to tell if they are running. The loudest noise they make now is the stepping through the target positions on a fast transition, since the ppm signal is updating the target position only every 20ms, which on a fast stick movement is quite a step. I am planning to filter this by interpolating the the ppm information. Also I will try to mix in D-control for better stability. It is stable now, but the damping is not very much, and I want the code to run on different setups without adaptation. BTW, the current consumption has dropped significantly too. Very good for the nano squall...

Not such good results on the tiny rx yet, bad range still. I prepared a test board to find out a suitable setting. One of the next steps will be the bl controller with the A3903 bridge.

Cheers,
Chris
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Old May 29, 2012, 05:03 PM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
11,148 Posts
Sounds like lots of R&D going on over your end Chris! Thanks for the update.
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