This article is from the Robotics FAQ, by Kevin Dowling firstname.lastname@example.org with numerous contributions by others.
The Mini Board is an outgrowth of the MIT 6.270 robot course and
design project. It is a small and inexpensive design for a controller
board based on the ubiquitous (yet sometimes hard to find) 68HC11
The Mini Board 2.1 Extended is the latest version of the Mini Board.
It is based on the Mini Board 2.0 Extended (see file
pub/projects/miniboard/docs/mbextend.txt ), and includes the
following new features:
* full six-wire SPI jacks include power, ground, and all four SPI
* optional diode protection prevents reverse-polarity voltage input
when using DC power jack.
* power and ground on Port A headers may be bridged to motor power
and ground, allowing RC servos to be plugged directly into the
Port A header (when using a 5.5 to 6v power supply).
* extra space between PLCC socket and female header connectors to
allow for newer, slightly larger PLCC sockets.
* mounting holes drilled for single RJ11 jack (for RS-232 serial),
saving money on triple RJ11 jack if SPI ports are not to be used.
Download the file pub/projects/miniboard/docs/mb21ext.PS.Z to see
the silkscreen of the new board.
The MINI BOARD 2.1 is a complete embedded computer board for robotic
applications. It can directly power four DC motors and receive inputs
from numerous sensors. Its miniature size (smaller than a business
card) makes it suited well for mobile applications as well as other
It can be programmed in 6811 assembler code or C for stand-alone
operation, or it can serve as a serial-line based controller operated
by a desktop computer.
overall dimensions: 3.3" by 1.86", smaller than a business card. If
desired, an off-board serial connector can be used, allowing an
additional .6" of board length can be chopped off.
nearly all parts can be purchased from Digikey (including all
connectors and switches). Extensive use of resistor packs minimizes
uses Motorola 68hc811e2 microprocessor with 2048 bytes of internal,
electrically erasable PROM and 256 bytes of RAM.
four motor drivers for bidirectional control of small DC motors (up
to 600 mA current, 36 volts each motor).
eight analog inputs; eight digital inputs or outputs; several timer
and counter I/O pins, all broken out to convenient header ports.
on-board 5v regulator allows board to be powered by any DC power
source from 5.6 to 36 volts.
RS-232 compatible RJ-11 port for communication/program download
between host computer.
two modular high speed serial jacks, allowing networks of multiple
MB 2.0's to be constructed using common 4-wire phone cable.
Multiple-mastering bus protocols supported.
optional battery level monitoring using voltage divider from supply
voltage before regulation.
XIRQ line broken out to a pad: when this line is given 12.5v, an
'hc711e9 chip with 12K of EPROM can be programmed in place.
MS-DOS, Macintosh, and Unix software provided for downloading
programs to board. 6811 monitor program provided for recording changes
in sensor state, controlling motors and interacting with other board
features over serial line.
C/assembler libraries provided for code development using Dunfield
Development Systems' Micro-C compiler, and ImageCraft's freeware icc11
C compiler. A fifty-page manual describing how to build and operate
the Mini Board is on-line on the FTP server:
People who don't have access to anonymous FTP can do FTP-by-mail,
provided as a public service by DEC. Send a message containing the
single word "help" to "email@example.com" for instructions.
Also on-line is software for programming the Mini Board from MS-DOS,
Macintosh, and Unix machines.
"Douglas Electronics, Inc."
2777 Alvarado Street
San Leandro, California 94577 USA
Douglas Electronics has been a manufacturer of prototyping
"breadboards" for over 40 years, and we also manufacture hundreds of
custom order printed circuit designs every month for people using our
Macintosh-based CAD/CAM software. One such user of our software is
Fred Martin, of MIT, who is the designer of the MiniBoard. We have had
several requests from people wanting a few MiniBoards of their own
over the years, so we figured we might as well stock them if we could.
Douglas Electronics, a Macintosh PCB CAD software house and a
commercial PCB fab facility, is a distributor of blank Mini Board
PCBs. [Thanks to Bill Schuler@douglas.com]
Pricing for the new mini-board is as follows:
1 board only ................. $ 10.00
2 to 9 boards ................ 7.50 ea.
10 to 50 boards .............. 6.25 ea.
50 and over .................. 5.00 ea.
Shipping is specified by and paid by the customer, and California
residents are subject to state sales tax. These are bare boards only
(we don't sell assembled units or kits) but all of the parts you need
to populate the MiniBoard should be available from common parts
suppliers such as Digi-Key, Newark, etc. and a silkscreened legend on
the board helps you put everything where it belongs. Douglas accepts
all major credit cards. There is also a dollar volume discount on
Douglas' breadboard products, that applies over and above the
per-board quantity discounts, as follows:
For more info see:
Three individuals are independent suppliers of Mini Board technology:
* Gregory Ratcliff , 1763 Hess Boulevard, Columbus, Ohio 43212;
(614) 487-0695 Greg sells blank boards for $6, parts kits, and
assembled boards. Please contact him for information. You can also
send him an order directly.
Make checks out to The Progressive Solution and mail them to him
at 1763 Hess Boulevard, Columbus, Ohio 43212; call him at (614)
487-0695 for more information.
$66.00 Parts kit of all parts that mount on the PCB, less PCB (see
above). Assembled boards will also continue to be available....
$82.00 Assembled and Tested with DLM 2.0 downloaded (we need that
in to test...of course you could overwrite the dlm)
$2.00 Fred's 45 page document set...only with board order.
Shipping in the USA: $3.00 per order... regardless of quantity.
Delivery is based upon demand.
* Mark Reeves 1117 Braemar Court, Cary, NC 27511; BBS and voice
(919) 481-3170 (voice hours from 5-7 pm EST). Shipping - all
orders will be shipped ASAP, we do not need to wait for a certain
number of orders (although there may be delays while certain parts
are gotten). If a delay happens you will be notified by email or
postcard. No check or MO will be cashed until the order is ready
PRICES (subject to change without notice) All kits include a PCB,
a kit without a PCB will be $5.00 less. A kit without the 1 RJ11
adpt will be $2.50 less, a kit without the 3 RJ11 adpt will be
K0 - a super basic kit, does not include any RS232 stuff, or motor
drive items, inductors, or most of the other discrete components,
it does have a PCB, CPU, socket, one 36 pin header, and a few
other items. Good for TTL level RS232, via some other chip, for
the person wants to use the board for expansion purposes, or
whatever. Contact us for price.
* K1 - basic kit all parts needed to get a board up and going, one
RJ11 jack, no headers, for the true hobby person $41.00
* K2 - same as above, but has all header connectors (3 female, 2
male - 36 pin header connectors) $46.50
* K3 - basic + motor controller the full kit with all needed parts,
with all LED's and motor controller chips, one RJ11 jack $57.50
* K4 - full kit same as K3, but has the 3 RJ11 jacks for
interconnecting with other boards $60.00
* B1 - bare PCB board, double sided, extended version silk screened
parts location, etc. $5.00
* J1 - a DC power jack and power switch for the board. Use if the
screw power connector is not used; this would work with a plug in
power supply. Note- these items are sold at cost, they are not
Add $25 to any kit to get it built, add an B to the kit number, i.e.
K4-B or K4-B-A for the 68hc11A1 version of the kit. All assembled
boards will have all parts soldered on them, but to meet FCC
requirements there will be minor work to be done ( you have to install
NOTE: the basic kits do NOT include the motor controller chips or the
motor LED's, they do have the RS232 parts, they are for people who
want to use the board for things other than robotics. No speaker or
sensors are included. All motor controller chips are the TI version,
1A drive current. All prices are subject to change without notice;
please e-mail to check if prices have gone up or down since this
Mark is a supplier of the recent board revision called the "Mini Board
2.0 Extended." This version of the Mini Board includes a power switch
and DC power jack for ease of use. Please see the file
pub/miniboard/mbextend.txt for more information.
CW Technology, Wally Blackburn
Miniboard 2.1 Extended Kit: $84US
Miniboard 2.1 Extended Assembled/Tested: $109US NOTE TO INSTITUTIONS:
Any order to a school, company, or any other large institution will
ONLY be shipped via FedEx at an additional $10US. This is to avoid the
"lost in the receiving department syndrome" that often occurs in these
Send orders to: CW Technology, 7328 Timbercreek Court, Reynoldsburg,
OH 43068-1181. COD orders can be sent via e-mail or by calling
Hard copies of the Mini Board manual may be ordered by sending a check
payable for U.S. $5 to "MIT Epistemology and Learning" at:
"Epistemology and Learning Publications"
MIT Media Laboratory
20 Ames Street
E15-301, Cambridge MA 02139.
There is now a mailing list for discussing the board. The purpose of
the mailing list is to discuss robot controller boards, and robot
control in general. In particular, the list will be used to support
the Mini Board 2.0 and 6.270 board design by Fred Martin and Randy
Sargent of MIT. However, any and all traffic related to robot
controllers is welcome.
Administrative address: firstname.lastname@example.org
(send a message containing the word "help" for directions) Mailing
list address: email@example.com
Please DO NOT send administrative things to the main mailing list
address, as then everyone will get annoyed.