Newsgroups: comp.robotics
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From: sasrer@unx.sas.com (Rodney Radford)
Subject: Re: PIC chips
Sender: news@unx.sas.com (Noter of Newsworthy Events)
Message-ID: <sasrer.768148245@cinnamon>
Date: Thu, 5 May 1994 14:30:45 GMT
References: <2q8dp6$7kq@panix.com>
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Organization: SAS Institute Inc.
Keywords: PIC PICSTART-16B
Lines: 45

kwas@panix.com (Chris Kwasnicki) writes:

>Has anybody used the PICSTART-16B and associated chips (PIC16/17).
>I'm interested in their usability with robotics/home control.  Basically,
>I would like to string a couple of these puppies along a RS-485 network
>to handle the I/O side (motor control, checking switches and sending a
>packet only if a change, etc.) talking back to central controller.

>I had picked up the the 68HC705 kit Motorola offered, but the 705
>simply doesn't have enough pins for my projects.

I am doing the same thing that you suggest above. I have a 386dx20 PC
motherboard as the main processor tied together to various other 
peripheral microcontrollers.  I am currently working on a closed-loop 
speed control system for the base motors using a PIC16c54 for PWM control
(two 8bit channels, data passed via an 8bit data bus) and another processor
(posibly a 6811 variant) for the PID calculations and monitoring the
shaft encoders.  

Originally I was going to use the ACCESS.bus protocol for tying the
various modules together. However after further investigation it looks
like the software overhead for each of the ACCESS.bus peripherals may be
more than it is worth for my purposes.  I plan on using some of the
advantages of ACCESS.bus in my design - but cut out those that I don't need.

The first two months of the project were involve with building the body
(aluminum riveted frame, 3x12v gel cels, each 8AH, 2 very strong motors
from a kid's electric ATV) - the body was recently tested to be able to
carry a 160lb weight (one of the developers).  I then bought some laptop
switching power supplies that will generate the necessary voltages from
the 12v gel cels and have mounted the motherboard.  At this time, I am
working on the design of the motor microcontroller - the first in a long
list of controllers to be built (one for an ascii LCD display, one for
bumper/battery monitoring, one for sonar measurements, and some for
RC servo and stepper controls).

Let me know if you need additional information - and please keep me posted
of any progress you may have. Thanx.


--
---
Rodney Radford,     Senior Systems Developer,  Image Technology Group
sasrer@unx.sas.com  SAS Institute, Inc, Cary, NC 27513  (919) 677-8000 x7703

