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Old Feb 16, 2004, 09:29 AM
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mmormota's Avatar
Budapest
Joined Jul 2003
2,579 Posts
Hi, Mr DIY,

Yeah, just talking about it is easier... :-)

I am thinking about developing such a beast. But there are some parallel developments - not sure if the results of them will be free.
If there will be a free design available soon, it is a waste of time to develop another one. (Takao's hw design is effective and simple, if he publishes the final code too, hard to make anything better...)
And here is your and KreAture's work too.

If your and the other designs are not planned to be free, it is more interesting for me to develop a publicly available free one.
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Old Feb 16, 2004, 11:46 AM
Registered User
Akron, OH
Joined Feb 2004
3 Posts
BLDC free design

I have an open design posted here;
http://groups.yahoo.com/group/osmc/f...LDC%20control/
or go to
http://groups.yahoo.com/group/osmc/files
and look for Rods BLDC control.
It's for a 100A plus control, but the power
and control board could be modified to make a smaller
control.
I have one version of this design on a 2.5" round board by
7/8" tall.
The files require expresspcb,
www.expresspcb.com
which is also free and goes up to 4 layers.
Rod
www.qsl.net/w8rnh
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Old Feb 17, 2004, 01:30 AM
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Mr DIY's Avatar
South Africa
Joined Aug 2003
587 Posts
Rodhower

I did know about the open source project, but never really had a look at it. My initial thoughts at that time was that this developmental project was aimed a robotics and probably Robot Wars. The supplied links above pretty much confirmed my initial thoughts and to be really honest, there is nothing there that caught my attention. The controller board is way to big, but as you already said, it could be made smaller. But if one is to go to the trouble of reducing it (I suspect you will still not get it small enough) you might as well do your own thing if you have the ability.

Never the less, there are people out there that do not have all the required skills, and will find this project helpful, as no doubt, many have. Well done to the Yahoo group people for doing what you have done. Great to see you guys pull this one off.

Mmormota

You should go with you idea, as you never know what might happen to possible competition to your idea. You may be able to do it better and simpler and therefore have the advantage. At present, I do not know what I want to do with mine when I have it 100% finished… which should be in a months time. I suspect mine is a little too difficult for the average home constructor due to 0603 caps/resistors and fine-pitched devices. My new PCB is reasonably tightly packed in order to keep size as small as possible. I was considering supplying the local market at home with built units, as standard commercial ones are very expensive. Time will tell.
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Old Feb 17, 2004, 08:50 AM
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Tokyo, Japan
Joined Nov 2002
868 Posts
Mr DIY,

>Takao .. What is your ADC conversion speed in uS?

8MHz/2=4MHz, 250nS

ADC needs 13 clocks.

250nS x 13=3.25uS

Basically, the AD is 10bit type.
But, As the manual says high speed clock reduces the resolution.
That is why I measured it with 4MHz.

If I could use ATMega8 with 16MHz clock, Then .... I am not sure.
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Old Feb 17, 2004, 09:16 AM
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Mr DIY's Avatar
South Africa
Joined Aug 2003
587 Posts
Hmm ... Takao .. I see what you are doing..

BUT ... the data sheet says that a suitable clock frequency must be chosen between 50 - 200 KHz to drive ADC module. So at 200KHz, that results in 5uS x 13 clocks = 65uS. I suspect now that this 'conservative' figure is for low power consumption and what works best for 10 bit resolution.

Maybe I should try some radical over clocking tonight and see.... Thanx for the feedback Takao.

Brian
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Old Feb 17, 2004, 09:24 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,927 Posts
Discussion continued overhere, a new BLDC thread in the "DIY Electronics' subforum:
http://www.rcgroups.com/forums/showt...hreadid=200567

Groeten Ron
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Old Mar 01, 2004, 06:49 AM
Registered User
Tokyo, Japan
Joined Nov 2002
868 Posts
New chip

I had found one interesting chip.

http://www.silabs.com/products/micro...sig_matrix.asp

The development tool is $99!
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Old Mar 01, 2004, 07:46 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
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Takao, the discussion is continued overhere, in the "DIY electronics" subforum:
http://www.rcgroups.com/forums/showt...hreadid=200567

Groeten Ron
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Old Sep 21, 2004, 04:16 AM
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Joined Sep 2004
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New chips for BLDC

Dear Mr.Takao Shimizu ,

I am very interested in your product of BLDC http://www.rcgroups.com/forums/show...8&postcount=148 Control. I would like DIY the BLDC, but cannot find MLH 6643, what IC can repla it. Your promptly answer will be very appreciated.

fsxhqsg_sg@yahoo.com

Thanks.
Best regards.
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Old Sep 23, 2004, 06:23 AM
Registered User
Tokyo, Japan
Joined Nov 2002
868 Posts
fsxhqsg_sg,

>MLH 6643

O, oo...
I made a mistake written.
It is "LMH6643", rail to rail full swing OP amp.
This device has 100mA drive capability with 130MHz responce.
Good enough for any high input capacitance FET drive as high current motor drive.

http://www.national.com/pf/LM/LMH6643.html

The schematic is up-dated(also, I had written the GND mark on power line).

Sorry about that,

Takao

Quote:
Originally Posted by fsxhqsg_sg
Dear Mr.Takao Shimizu ,

I am very interested in your product of BLDC http://www.rcgroups.com/forums/show...8&postcount=148 Control. I would like DIY the BLDC, but cannot find MLH 6643, what IC can repla it. Your promptly answer will be very appreciated.

fsxhqsg_sg@yahoo.com

Thanks.
Best regards.
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Old Sep 23, 2004, 09:21 AM
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Joined Sep 2004
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New chips for BLDC

Takao Shimizu

Your promptly answer will be very appreciated.

Thanks.
Best regards.
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Old Feb 14, 2005, 12:59 PM
Bolton barry
Bolton, lancashire UK
Joined Feb 2005
2 Posts
Brushlees controllers

Since I am new to all this, this may not get through ! I logged on beacause I felt sure there may be some way of making a cheap DIY Brushless controller -- but looking at all the messages about this it seems to be beyond me! I am building a 42" span electric Lancaster with 4 KP02 motors off 8 cells. the motors are only marginal, and having experience of other brushless models, wondered if 4 small brushless (CD-Rom? )motors would do -- but 4 speed controllers? is it possible to run more than one brushlees from one controller, if the motors sere "fired up" one by one, and "caught" before each one had stopped spinning? I suppose we all want something cheap! Bolton Barry
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Old Feb 14, 2005, 01:45 PM
Impossible? Hah!
KreAture's Avatar
Oslo Fornebu, Norway
Joined Jun 2003
3,074 Posts
Identical motors with identical load can run in paralell on a single controller. They start together and stop together.

However, a big plane may display different load to a prop inside the turn compared to one on the outside. Result may be loss of synch and power...

I am setting up just such a bird to test how well it works in real life.
http://www.kreature.rchomepage.com/p...at_twin_04.jpg

Both motors are capable of 150w or so and are run by a single 45 amp ESC from 3s LiPo.

The bird is made to be a floater so any loss of power will not cause a crash.
Will know soon how it performs
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Old Dec 24, 2005, 06:25 PM
Registered User
Akron, OH
Joined Feb 2004
3 Posts
Messages end in Feb?

I was looking through the messages and realized there is nothing past Feb 2005.
I haven't monitored this list since last year and was wondering where the new messages are located.
Thanks,
Rod
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Old Dec 25, 2005, 05:22 AM
Registered User
Tokyo, Japan
Joined Nov 2002
868 Posts
I am trying the brushless controller.

http://www.rcgroups.com/forums/showthread.php?t=200567

See near the last page.
You may get many info. to design.

Takao

Quote:
Originally Posted by rodhower
I was looking through the messages and realized there is nothing past Feb 2005.
I haven't monitored this list since last year and was wondering where the new messages are located.
Thanks,
Rod
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