Brushless ESC are now a very cheap device which can be bought from our friend hobbyking. These ESCs are great for planes but they don't quite fit what we need. So lets reprogram them to do what we want.

Controllers are now using Atmel and Silicon Labs microcontrollers. Both can be reprogrammed, however silicon labs MCU requires a different programming adapter.

For Code See
www.launchpad.net/brushed

Brushed Motor ESC
The brushless ESC consists of 3 half bridges. It should be possible to repurpose two of these to make a single H-bridge. This is similar to a brushed motor mode which is available in some high end controllers. This should be able to be done with most HK controllers.

Goals for Brushed Controller
This TODO list is much more complex in reality due different code for SiLabs and Atmel MCUs

Proof of Concept - Complete
Fully Functional Controller - Complete
- Add max slew rate - Complete
- Exponential rates - Complete
- Programmable mode - Complete
Identify suitable controllers for classes - Complete

Controller State
Special 2in1 Antweight Controller -Complete
Battle Tested in Antweight - Complete
Battle Tested in Beetle - Complete
Battle Tested in Feather- Complete

Battle Tested in Lightweight - Under Development
Battle Tested in Middleweight - Under Development
Tutorial - Complete - http://www.robowars.org/forum/viewtopic.php?t=1609

My first aim is to be able to 2x Plush 30s to run scooter motors in a feather. The ESCs should be able to take it.

Here is a picture.


You can see the 6 programming pins. Just tracing them now.

http://dl.dropbox.com/u/815267/IMG_1008.JPG

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Last edited by marto on Sat Feb 05, 2011 11:35 pm; edited 2 times in total

As per discussions on MSN, I suggest looking at Turnigy Brushless ESC 85A w/ 5A SBEC ( TZ85A ). This looks like a more combat ready controller physically and the amperage and voltage ranges should be suitable for the featherweight class. The size, weight and price of the TZ85A are very attractive.

I'm prepared to purchase a couple of these to put towards development.
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So from left to right in the above picture.

1. Reset
2. VCC
3. Ground
4. SCK
5. MISO
6. MOSI

And we have a programming connector

And apparently this is the schematic.

http://www.rcgroups.com/forums/showatt.php?attachmentid=3693455&d=1293741089
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

The code on the ESC appears to be locked. It can be read but its just a repeated pattern



Here is the code.
http://dl.dropbox.com/u/815267/Plush30/Plush30-Read.hex
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Steven Martin
Twisted Constructions
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Ok Fet details for the Plush 30s

4407GM
http://dl.dropbox.com/u/815267/Plush30/4407GM.pdf

IRF 932

http://dl.dropbox.com/u/815267/Plush30/P932M.pdf
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Steven Martin
Twisted Constructions
http://www.botbitz.com

quote:

---

Originally posted by Jaemus:
fast work! got a video?

---

I've been discussing with Steve on reprogramming various controllers for different weight classes.

Antweight
H-KING 10A @ $5.98
HobbyKing 12A @ $7.81.

Beetleweights
TURNIGY Basic 18A @ $13.99
TURNIGY Basic 25A @ $15.86

Featherweights
Turnigy Brushless ESC 85A @ $36.59
TURNIGY Sentilon100A HV @ $84.01

Research still has to be done into each controller, but if it does prove successful, it might mean a new era for cheap, disposable speed controllers for everyone.
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Just to add some extra stuff to this project. If you blow up one side of h-bridge (half-bridge) on these controllers, it should be a simple case of reprogramming them to use the spare, 3rd half-bridge instead so the controller works as normal again. Therefore you might get a chance to blow it up twice before throwing it away
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Uploading video now with moar reverse just to prove it actually does work.
http://www.youtube.com/user/QRSClub#p/u/0/mAbSaG7nFBQ

As for amps I am not sure. Only way we will know is to test. But odds are for beetles it will still be cheapest option. Even if we can't do feather sized motors.

Also the schematic I uploaded is incorrect High C actually = High A

I am going to start a launchpad repository for the code as revision control is something which I really need. As I have a tenancy to throw away all the code then realise I need it all back....
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Steven Martin
Twisted Constructions
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Last edited by marto on Sun Feb 06, 2011 9:16 pm; edited 1 time in total

I am pretty sure it should work. I just probably have bugs in my Code.

I am going to strip it back a little tonight and just see if I can get Bang-Bang with a RC input working. Might also wire up a LED to the spare motor wire for debugging. Finding uses for that extra channel already.

I am still wondering why no one has done this before.....

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

So latest.

http://www.youtube.com/watch?v=ZhOPOTYCwdk

If you want to see code check out http://www.launchpad.net/brushed

Ah was quite a few stupid mistakes in the code..... No PWM atm but that is to come.

Brett if you see this could use a bit of input on the code particularly for switching the fets.

Steve

Edit: Also updated first post.
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Steven Martin
Twisted Constructions
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After quick look at PWM code I think there is something wrong with my timer setup. Sleep will tackle full PWM tomorrow.
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Words do not describe the awesomeness, even proving bang/bang control via RC is enough, the days of grossly overpriced esc's are nearing their end... Wonder if any of the american guys have seen this yet...
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YEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH

Good work Steve.
I'll start testing the code on a few of my BESC's when I get back from NSW. I also have a few other ideas to bouce off you with regards to functionality.
Also, cheers for making me the 'Driver' on Launchpad
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