Hi,
Mr. Takao has version 1.3 of his code posted..

http://www.rcgroups.com/forums/attac...postid=1530527

Regards

Do a search for the ST72141 part it is a 3phase motor controller with the bemf module built into the device.

They even sell a developement kit with code and a motor

http://www.st.com/stonline/products/...72141-0101.pdf

DanC,

Did you also find a supplier for this part? I couldn't locate it in any of the standard US suppliers - guess I will have to look a little harder. Couldn't even find it at Arrow who lists STMicro on their linecards.

This device is quite interesting since it is an 8-bit microcontroller with 8 channels of 8-bit A/D, 14 configurable I/O and such.

The negatives are that ST products are typically double the cost of AVRs or PICs. The development system has a MSRP $695. (I could buy 12-13 10-12Amp brushless controllers for that price!) It is also ROM, OTP or EPROM based - would be tough to tweak the code.

-John

whanderson;
I have tried checking everything, BEMF is fine, connections are fine. Still can't ge tto arm. I will try the changes you suggest and try again.

Thanks!


Mr. DIY;
Thank you for your schematics a while back and that setup looks really nice. I am happy that you are getting things working.



I think we are getting somewhere with this project, there are some really sharp people posting here!

P.S. Mr. DIY, where do you get your PCB's made? Very nice.

Originally posted by zagisrule!
whanderson;
I have tried checking everything, BEMF is fine, connections are fine. Still can't ge tto arm. I will try the changes you suggest and try again.

Thanks!


Mr. DIY;
Thank you for your schematics a while back and that setup looks really nice. I am happy that you are getting things working.



I think we are getting somewhere with this project, there are some really sharp people posting here!

Matt,

A couple of questions. When you start up your controller does the motor beep? Does the motor move at all? What motor are you using? Have you tried Takao's latest software version mentioned earlier in this thread?

BTW - I get my boards from www.expresspcb.com. Their layout and schematic software is free. Their miniboard is $60 for 3 ea. 2 1/2 x 3 3/4 2 sided plated through holes, 3 day turn around. This picture is an example of their work. PCBexpress does similar work, but are a little more expensive.

Hi. I've been looking at all the chips selected for theese designs and most of em are not good at all. The 141 chip from ST needs a center-tap to work right.

There is however a great chip from Toshiba called TB6537F. Datasheet avaiable here:
http://www.semicon.toshiba.co.jp/td/..._datasheet.pdf

Basically, this is a fully-fledged brushless controller. It has most of what it needs buildt in.

Features:
- PWM input (wants about 16 khz) for speed controlling
- buildt in startup logic
- stops when no pwm is received (PWM = 0% duty)
- small and light (24 pin SSOP only 0.32 grams!!!)
- over-current protection
- no center-tap needed
- programmable lead angle: 0, 7.5, 15 and 30°

Needs:
- 2 external opamps, 1 for OC detection and 1 for commutation wave amplification.
- 1 3-phase driver array or 6 FET's + 3 drivers for the P-FETs.
- crystal/oscillator (1-10MHz)

and a PWM signal!

I am working on getting my hands on one of theese chips. They should integrate very well with any small microchip both AVRs and PICs.

With a 10 MHz resonator max speed should be about as good as the MGM controllers.

Hi Everyone,

I have gotten PCB's done from ExpressPCb in the past, but I was curious where that nice solder-masked PCB Mr. DIY had came from. Just curious.



Kreature;
I have tried very hard to get the same chip, then use a PIC to drive it and act as the rx interface. I called maybe 6 distibutors across the US and they said that the DIP package (for prototyping) was unavailable and samples for the chips in SSOP form will take months to arrive and nobody has any stock to just buy the chip. I don't think that we could get a hold of many unless we "ordered" a large quantity like a manufacturer. Have you managed to get some sent to you and are waiting on the mail or have you yet to try? If you are getting some samples, request a few and I would be glad to pay postage for you to send one out here. Seems like a promising chip, if we can get it.


Whanderson;
The motor beeps continuously, a Mega 16/15/3 is the only commercially made motor that I have and I have been using to test.


I will test again with software changes and report the results.

I have been in contact with multiple suppliers, but have yet to hear from some of them. Those I have heard from are positive to the idea of getting me some samples and say they are working on it.

I am doing this through the university. This helps a lot as the companys know that it may lead to mass-production.

That is great Kreature! I am betting that these chips have alot of potential.

My first implementation will be a tiny ESC capable of max 4-5 amps. (With a small 1A BEC)

It will be to try and use cdrom motors. (They are after all an abundance.)

Originally posted by zagisrule!
Hi Everyone,

I have gotten PCB's done from ExpressPCb in the past, but I was curious where that nice solder-masked PCB Mr. DIY had came from. Just curious.

ExpressPCB will do solder mask and other features if you want to spend the money. They have a number of production services including 4 layer boards.

But aren't that a insanely expensive way to do it ?

I'd have to pay over $20 pr board if I use a real boardhouse for my simple stuff...

Originally posted by KreAture
But aren't that a insanely expensive way to do it ?

I'd have to pay over $20 pr board if I use a real boardhouse for my simple stuff...

Sounds pretty reasonable to me for boards for SMT parts, double sided, plated through holes, and solder plated.

That was bare boards. No components.
Besides, I etch my own for $1 a board.