p.Brain ds24 Hardware Design

p.Brain-ds24 Robot Controller

p.Brain ds24 Hardware Design

Postby Matt Denton » Wed May 21, 2008 9:15 am

Hi,

As some of you may know I have been working on a release version of my p.Brain-ds24 robot controller, and I'm just finalizing the hardware design. The p.Brain will come in a couple of different flavors:

A) Hardware only, leaving the user to write their own programs using MPlab and a suitable PIC programmer. I will add code examples to my website for accessing the various on board I/O and PWM multiplexor. It should be noted that the dsPIC33F series processor used has an average flash write life of 1000 writes, however, microchip only guarantee a minimum of 100 writes!

B) Hardware plus dedicated firmware such as a hexapod engine. I hope to add a boot loader to the p.Brain for easy firmware updates. This is aimed at the user who wishes to control a hexapod at a high level using serial commands, but does not want to get into the locomotion algorithms etc.

At some point I may release hitec C library versions of the hexapod engine, however, this will be at the bottom of the list.

Download the PDF here: pBrain-ds24.pdf

Any comments or suggestions welcome.
Matt Denton
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micromagic systems ltd
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Re: p.Brain ds24 Hardware Design

Postby RayRenteria » Thu May 22, 2008 12:23 pm

Matt,

Did you design the p.Brain? Is it available for sale? I don't see it on the product listing of the Micromagic Systems site.

If so, are the IK translation and rotation algorithms demonstrated in your hexapod videos available as part of the purchased system?

--Ray
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Re: p.Brain ds24 Hardware Design

Postby paulp » Thu May 22, 2008 1:39 pm

Hi Matt

Nice to see another possibilty coming to the market at last.

I have tried several different controllers over the last 18 months and each was lacking in one or more areas.

Most are dedicated as Serial Servo Controllers and are limited usually by the max baud rate or the number of servo's they can handle.

Many are Atmel based and to achieve 115200 baud they usually run at 14.7456Mhz which means they run at a fairly low clock speed.

Some come with the ability to add your own code such as the Atom Basic units but they are 'Basic' and only control up to about 12 servos. Many will only do 8.

What you are proposing seems ideal (to my expectations at least).

The Hexapod engine version would be great for those times when you just want to run the thing round the room / garden. The self-coding version would meet the needs of those with a challenge in mind. It would obviously be capable as can be seen from your videos.

My concerns are to do more with my own limitations than those of the board. I have worked in 'C' before but am by no means an expert and writing optimised functions would be beyond me. You mention some libraries you would make available, any idea yet what these would entail. Most people seem to stumble on interrupt driven UARTS and accurate PWM.

I do like the modular design of the SMB and pBrain units. Could then just buy 1 SMB and switch between gait engine and self-programming modules.
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Re: p.Brain ds24 Hardware Design

Postby Matt Denton » Thu May 22, 2008 6:06 pm

Hi Ray,

RayRenteria wrote:Matt,

Did you design the p.Brain? Is it available for sale? I don't see it on the product listing of the Micromagic Systems site.


Yes the p.Brain is a denTON design :) , not yet available for sale, I have finished the hardware design, and am just about to send the PCB's off for manufacture. Once I have the PCB's back I need to get them populated, so all going well I think it will be about 4/5 weeks before I have the first production p.Brain.

RayRenteria wrote:If so, are the IK translation and rotation algorithms demonstrated in your hexapod videos available as part of the purchased system?

--Ray


I am trying to make the system as modular as possible. So you would purchase a p.Brain-ds24 controller and a p.Brain-SMB mother board (or use your own design of motherboard). The p.Brain will either come bare or with a bootloader and a basic serial servo controller on board, this way you can get a servo waggling straight away.

I will post C code and examples of how to generate PWM signals and UART code, maybe I will post the serial servo controller project so that if people wish to develop there own code they have somewher to start. For this, MPLAB, a C compiler (I use Hi-Tec's) and an ICD2 programmer will be required.

If you do not wish to develop your own code, the idea is that you purchase the p.Brain-Hexapod engine. This engine will do most of what you see my hexapods doing, and is configured via the p.Brains serial port and terminal software. Once the hexapod geometry, and servo settings are configured, the hexapod can be controlled by sending simple commands via the P.Brains controll port ( TTL UART or bluetooth with additional module). The idea is to load the p.Brain-Hexapod engine using the bootloader and a serial lead.

I'm also working on an aluminium hexapod kit based on my Hexapod V4b design. This kit will use hitec servos, and I will have a configuration file ready to load onto the p.Brain-Hexapod engine.

That all probably sounds quite confusing... hopefully it will become clearer as this forum progresses. :)
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Re: p.Brain ds24 Hardware Design

Postby Matt Denton » Thu May 22, 2008 6:10 pm

Hi Paul,

paulp wrote:Hi Matt

My concerns are to do more with my own limitations than those of the board. I have worked in 'C' before but am by no means an expert and writing optimised functions would be beyond me. You mention some libraries you would make available, any idea yet what these would entail. Most people seem to stumble on interrupt driven UARTS and accurate PWM.


What I'm thinking is that I will write a serial servo controller that will come with the p.Brain as standard. This SSC will have all the necessary code for interrupt multiplexed PWM and interrupt driven COMMS, if I share this C code it should give you a good starting place.

paulp wrote:I do like the modular design of the SMB and pBrain units. Could then just buy 1 SMB and switch between gait engine and self-programming modules.


Exactly, or once you have played with the SMB, you can make your own motherboard with out having to worry about any surface mount as this is all on the p.Brain controller.
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Re: p.Brain ds24 Hardware Design

Postby paulp » Fri May 23, 2008 5:09 pm

That would be an excellent starting place.

Unlike many, I have no formal programming experience, all my coding experience is from observing how others have done it. Perhaps not ideal and sometimes a very steep learning curve.

I would suggest that any code you do release is covered by something like GPL or lesser GPL. I can never remember which is appropriate for this kind of code.

Perhaps start a library that all can contribute to, or did you already say that?
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Re: p.Brain ds24 Hardware Design

Postby Matt Denton » Mon May 26, 2008 8:55 pm

paulp wrote:I would suggest that any code you do release is covered by something like GPL or lesser GPL. I can never remember which is appropriate for this kind of code.

Perhaps start a library that all can contribute to, or did you already say that?


Don't really know the ins & outs of GPL, but I'm sure it would probably require something like this.

A Library may not be a bad idea, but I have lots of other stuff to get going first :)
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Re: p.Brain ds24 Hardware Design

Postby paulp » Tue May 27, 2008 8:22 pm

Wondered why it was quiet, It seems the email notification isnt working.
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Re: p.Brain ds24 Hardware Design

Postby Matt Denton » Wed May 28, 2008 7:50 am

paulp wrote:Wondered why it was quiet, It seems the email notification isnt working.


Ok, will look into it again. :?
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Re: p.Brain ds24 Hardware Design

Postby Matt Denton » Wed May 28, 2008 4:36 pm

Hi Paul,

I just got a topic reply notification?? have been tinkering all day, am still confused! Forum notifications seem to work fine. Let me know if you get this notification.

Cheers.
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