Most of my current electronic projects revolve around the MC68HC11,
which is a neat little "computer-on-a-chip" complete with 512 or 1024
bytes of internal RAM, 512 of EEPROM, fast 8-channel A/D converter,
serial communications and various I/O ports. I'm using the 'E9, the
'E20, and the 'F1 versions which have 12K windowed EPROM, 20K windowed
EPROM or OTPROM, and 32K RAM/128K FLASH respectively. Many of my projects
have used the MIT Miniboard:
Electronic projects and software to download
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Here are some of the things I'm doing with the MC68HC11:
- A 68HC11 loader/debugger
(No Windows port yet)
This useful tool uses minimal resources on even the smallest
MC68HC11's, leaving you free to load and debug your programs
even in single-chip mode. It's a free download, all
I ask is that you send me a postcard.
- R/C car robot
A cheap full-control R/C car can make a
good base for a robot.
- Pan-tilt head
I modified the "neck" mechanism out
of a golf-ball typewriter to get a tough pan-tilt platform,
which has continuous 360 degree panning and 80 degrees of
tilt. I have yet to fit the servomotors to it, but the pictures
here should give you an idea.
- Direction-sensing sonar
The pan-tilt head needs this direction-sensing
ultrasound sonar unit, which uses my stereo version of the circuit
published by Gerry Coe, of Devantech. It's remarkably effective!
- Midi Percussion controller
This is a general purpose 64 channel data acquisition device
with serial output, except that the inputs can stretch pulses
from a piezo wafer, and the datacomms is either RS232 or MIDI.
The result is a board you could use for anything from a
burglar alarm to a drum machine. It can scan all 64 channels
in 1.4ms while generating serial output.
I'm using it initially to build a 5-octave vibraphone
controller for a musician friend. The prototype has only
two octaves, and the pads are made from flooring rubber,
vinyl and plywood. It's working great but I have a lot more
work to do in the software department before it's a
professionally usable instrument.
Initial tests show that it's capable of outperforming some quite
expensive drum machine controller hardware in a number of ways,
due to the novel acquisition and timing methods used to prevent
double triggering and false triggering.
The board is single-sided but compact, and was designed using
Circad. Sorry, you can't download the board design because I
am considering selling this design (and/or products built with
it). Contact me if you have a proposal!
- Floppy drive stepper-motor robot
This is one of those robotics rites-of-passage. It took only one
afternoon to build, which was mostly contructing a dolly wheel from
bits out of a printer, and is pretty gutless. I used the lowest
current steppers I could find in the hope of getting more efficient
ones, but they're just gutless. I must change them for some of the
other ten in my collection. It's also driven by a Miniboard.
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