Did you know...
Serial Wombats are No
longer for Sale!
It seems like the end of the Serial
Port and the rise of the Arduino hobby platform have
marginalized this product.
To fulfill the promise I made way back
in 2005, here's the source code: wombatfirmware.zip
You'll need the MPLab software from
microchip, and C18 compiler (Free / student version).
Start with the project file
wombat4620.mcp . After compiling and programming a chip,
make sure to set all eeprom bytes to 0, or the product
won't work right, if you aren't using a bootloader which
This code is now licensed under the
FreeBSD license, so you can use it in commercial products
if you like, without releasing your source code. See the
FreeBSD license for details.
I am no longer supporting this project.
Emails asking for tech support on this project are
unlikely to be returned.
Web Hosting for SerialWombat.com is
paid for through July 2012. After that, online
documentation may no longer be available.
Have fun, and thanks for your support
over the years.
A Serial Wombat:
- Is a microcontroller programmed with custom
- Connects to a PC, Palm-Pilot, WinCE handheld,
or other "Smart" Host device
through the serial port
- Acts as "Arms and Legs" by giving
the host device Digital and Analog I/O
- Uses a simple 8 byte protocol
- Is designed to be attached to the host device
- Provides up to 32 digial I/O pins
- Provides up to 13 Analog Inputs
- Comes pre-programmed. You don't download any
program to the Wombat; you send it commands
- Includes functions to reduce the work of the
host device, including servo control, stepper
motor control, LCD display control, keypad
scanning, filtering, averaging,
rotary-encoder and many other pin-modes.
- Can be upgraded by the user when new firmware
The Serial Wombat is a 40 pin, Microchip 18F4620 PIC
which comes preprogrammed with firmware to solve many
common interface problems. The Serial Wombat makes it
easy for people to interface things to their computer
without ever programming a byte of code into a
microcontroller. It talks to the computer over the Serial
Port, the easiest bidirectional port to program for. See
section of the Overview page for more detail on the
ideas which drove the creation of the Serial Wombat.
The Serial Wombat makes it easy to write software to
do more complicated things which can only be achieved
with the help of embedded software:
- Control up to 12 Servos from
the host computer, or set up a servo to respond
to other Wombat inputs
- Scan a matrix encoded keypad, and report and
remember button pushes for reporting to the PC
- Monitor a rotary
encoder and report the net number of
clockwise or counterclockwise turns to the PC
- Configure the Wombat to monitor for short
circuits and shut off an output within
milliseconds of a short condition, preventing
The Serial Wombat isn't just for PC's. Attach one to
an old Palm Pilot to create a portable,
powerful data aquisition and control system with a
graphic user interface. Or use a Wombat to add tons of
I/O and control options to your Basic Stamp project. See the Documentation and Protocol pages to get an idea of
the power, versatility, and ease of use of the Serial
The Serial Wombat has a built in bootloader. This
means that when a new version of software comes out, you
can download it into the chip yourself!
|Nov 13, 2009: Wow!
It's been a while
As you can see, it's been a
while since I've done a site update. Since the
last techincal update (July 19, 08), I've got a
new baby, and gone back to school to learn
Chinese. Quite busy! But have no fear, I've still
been filling orders and responding to
Tech-Support e-mail. I've also been working
sporatically on version 3.0 of the firmware. It
will add the ability to control the Wombat via
SPI rather than RS232. Is there a feature you'd
like to see in 3.0? Send me a note!
I've taken down the Forum. Since I set
it up I had like 3 threads on it. Basically, it
seems that everyone would rather email me for
support. The only people really using it are
spammers trying to increase the page-rank of
their WOW Gold Farming services. So, down it
goes. I'll miss the graphic, though...
I've also created a script to
add the pin mode code to many pages documenting
pin modes. That may help you understand details
of how the code works.
|November 11, 2008:
I'm cutting out a middle-man!
The news is always talking
about how legions of sellers are bailing out on
Ebay due to higher fees. As of now, I'm one of
them! From now on I'll be selling using a simple PayPal
shopping cart. What?
Who do you say owns Pay Pal? :-)
In addition, I've got some new items up,
including the LED display and IRDA kits mentioned
below. Just in time for the Hollidays, I'm also
adding a new 3-pack of Serial Wombat chips, at a
reduced price of $44.95, a 25% savings.
|July 19, 2008: A Serial Wombat in Your Bathroom. See how Robbert
van der Bijl uses a Serial Wombat to display how
much shower water is available from his Solar
Heating system. Thanks Robbert!
|March 21, 2008: Connect
your Wombat via IRDA A protocol chip from Microchip and a
surplus physical adapter, and you're on your way.
Check out the video!. A kit with all the parts
will be available starting at Notacon.
|March 19, 2008: I've been
invited to speak at Notacon in Cleveland, OH on April 4th through
6th. I met one of their founders a couple of
years at the Hamvention, and they sold Wombat
kits through their desk last year. I'll be
talking about how to anticipate the desires and
fears of people who may want to use a tool you
develop. There's lots of cool speakers,
and tickets are only $50 if you get them before
March 23rd. I'll have Wombat kits and other fun
trinkets for sale.
|March 17, 2008: Pin
Mode for SPI LED Display.
This SDK demonstration
creates a pin mode capable of driving an st2225a
based LED AlphaNumeric Display.
|February 24, 2008: Python
programming example created by Wombat Customer
Carl Nolf. Check out the PyWombat project on Sourceforge. Thanks Carl!
|February 8, 2008: SED 1330
Graphic LCD Driver. This add-on pin mode was created using
the SDK. It allows you to take easy advantage of
a really cheap graphic LCD sold by All
|February 6, 2008: Sample project in C. This sample
application is written in C, and should work on
most POSIX compatible systems, such as under
Linux and Cygwin for Windows. This was the first
thing I programmed with my new Linux based eee PC
ultra portable notebook. It includes code for
using the Wombat's generic HD44780 LCD driver.
|February 2, 2008: Firmware
version 2.2.0 is now available. This firmware adds pin modes for
datalogging, and minimum-maximum tracking. It
also fixes a lot of minor bugs I've found through
a new automated testing routine. Download
2007: Wombat Panel 2.0 is now available.
Lots of new features, plus
much improved sample code in the Wombat.cs class.
|June 18, 2007: Firmware
version 2.1.0 is now available. Only one change in this firmware: The
addition of a CTS hardware flow control pin (if
configured). Why the sudden interest in flow
control? Two hints... Download
June 1, 2007: We're #4...We're #4...We're #4. Apparently Google thinks we're getting
more important. Our page rank went from 3 to 4!
This is based on the number of pages that link to
this one, so a special thanks to everybody who's
out there promoting the Serial Wombat! I couldn't
do it without you!
|May 30, 2007: We had a great time at the
Hamvention. We did great
this year, selling out of most of the items we
brought to the show, including around 60 Serial
Wombat chips. For those of you who bought an
experimenters kit, I'm in the process of
documenting the parts. Check it out in the forum. After the show we also got a nice shout out in one of ARRL's newsletters. Thanks to everyone who stopped by the
|May 17, 2007: Version 2.0.0 is
out! With support for the
new SDK, a generic HD44780 driver, SPI master
mode, Remote control reading, and upgrades to a
number of existing modes, this is the most
important new release since We've started! Get
Wombat Forum is open! I'll
be answering most future support requests inside
of this forum. Hopefully, it will also build a
great user base. Check it out at http://forum.serialwombat.com (will redirect).
We're Going to the Hamvention! See you in
Dayton this weekend! Look for a new release of
the Wombat Panel, as demoed at the Hamvention,
within a couple of weeks. The source code for
controlling the Demo board will also be
|May 8, 2007: The
Wombat kicks it Old-School, with a sample programming framework for QBasic. Wow. That
sounded a lot less dorky before I typed it.
Still, the code is fun. Check it out.
|Apri1 29, 2007: Welcome to our
friends from Notacon! Thanks to
everyone who bought a kit at the convention!
|Apri1 21, 2007: Firmware Version 2.0.0 BETA3 is available. It
turns out that the previous beta wasn't
dangerous. The user reporting the problem had a
power supply issue. On the bright side, I went
thorugh the code looking for problems, and fixed
a few I hadn't previously found! (For those who
are curious, Beta 2 was only released
version of firmware has a bunch of cool new
features, including a Generic HD44780 LCD driver
pin mode, a Sony Remote Control reading pin mode,
a software UART receive mode, and more! Look for
documentation on these new modes coming soon!
|March 12, 2007: Beta
Temporarily Withdrawn One
of my customers is reporting problems with a dead
Wombat shortly after downloading the Beta. I'm
taking it down until we can figure out what
|March 11, 2007: Firmware Version 2.0.0 BETA and Pin Mode Software Development Kit BETA are available.
This new version will incoporate a lot of new
features, and should perform faster than the
version 1 releases. Additionally, there's support
for you to write your own Pin Modes in C and
download them into the Wombat! I'm still in the
process of writing the documentation, but check
out what's up so far. Feedback on this would be
|February 25, 2007: Support
over Skype. When I'm just
hanging around on my Lab PC, you can Skype me if
you need help. I'm doing this on a trial basis,
to see how it works. I work on Wombat stuff at
night and on weekends, so that's the best time to
the right should show my status.
|February 10, 2007: We've got one of
those fancy favicons
now... I figure it's just a
matter of time now before those venture capital
guys come knockin'...
On a more serious note, Version 2.0 of the
software is coming along quite well. Experiments
have shown my design for a Wombat Pin Mode
Software Development Kit will work. You'll be
able to write your own Pin Modes in C, and upload them to the Wombat.
Your firmware will work along with mine (not
replace it), so all the functionality you already
know and love will still be available.
|January 18, 2007: Can't figure
out how to open a serial port? How about a socket? This new sample application serves up a Serial Port on your PC as a
TCP/IP socket. Access it locally, or across the
|January 13, 2007: New Firmware
version! I know it's been a
while since a site update, but boy, I've been
busy improving things! Lots of pages have updates
with better documentation, and
firmware version 1.2.0
is available on the downloads page! This adds a
few bug fixes, plus two major new pin modes, Hardware Pulse Measurement, and 2D
Lookup table. Check 'em
|July 25, 2006: Communicate
with a Serial Wombat over Ethernet. Lantronix makes
a product called the XPort which allows serial
devices to be controlled through a Telnet
connection. Hooking one of these up was a snap.
Check out my quick review of the XPort.
|July 23, 2006: Our Second
Sample Application. The Serial Wombat iTunes Controller application written in C# can display
the current playing track on an LCD, and allow
you to change tracks, control volume, and
play/pause using a rotary encoder, potentiometer,
and button. Check out the video for a demo!
July 18, 2006: Documentation for counter
mode allows a pin to keep track of the number of
transitions that have occured since a pin was set to
counter mode. Inputs can be debounced if desired. This is
great for keeping track of the number of button presses
between queries from the host.
|July 6, 2006: Our First Sample
Application. The Wombat Panel
application written in C# makes it easy to test
out your Wombat. Download it to check out the
code, or just to use the application (an .exe is
in the zip file).
June 3, 2006: Fix for BOOT> problem.
Under some condititons it is
possible for the Serial Wombat's EEPROM configuration to
be corrupted. Firmware version 1.1.1
has been released to fix this problem.
May 23, 2006: Back
from the Hamvention! We sold a
bunch of Wombats and learned a lot about what people want
in the next version of firmware.
May 13, 2006: The Getting Started page is up, complete with video. See how easy it is to build the Serial Wombat
circuit, and turn an LED on and off from Hyperterminal.
May 8, 2006: SerialWombat.com will be
exhibiting at the Hamvention in Dayton,
OH, May 19-21! Come to inside booth 404 to see our various
demos, and pick up a Wombat with no shipping charges!
22, 2006: Matrix Encoded Keypad scanner documentation online. The
Serial Wombat can scan matrix encoded keypads and put the
keypresses into a queue, or provide it as public data for
use by other system pins.
March 23, 2006: Pulse on
Public Data Change
documentation online. Want to blink
an LED on reception of a byte from the host? Or beep a
piezo momentarily when a button is pushed or knob is
turned? The Pulse on Public Data Change pin mode makes
this easy, with no help from the host.
March 17, 2006: Command Processor cgi
Script is online. Want to send
cool, binary commands using text strings in
hyperterminal? No more tedious conversions. This page will do the
conversion for you!
2006: The support for our first HD44780 LCD display is complete. The Serial
Wombat now directly supports this 2 x 24 HD44780 based
display. Scroll one or both lines, and create your own
12, 2006: The support for the first LCD display is complete. The Serial
Wombat now directly supports the WD-C2401P LCD Panel.
Just download a string to the Wombat, tell the Wombat how
the pins are connected, and your message appears! Best of
all, this LCD is only $1.85 at All Electronics.
January 7, 2006: Slight restructuring
of the web site. The site is now
made up of a larger number of smaller pages. This should
make it easier for people to find things, both at the
site and by using search engines.
December 28, 2005: The documentation
for the Servo Driver Channel Mode is up! The Wombat can
drive up to 12 Futaba S3003 servos at once at 10 bit or
better resolution! We're pretty psyched about this
ability, since this guy wants 12 bucks for a chip that can only drive
5, at 8 bit resolution (See the edeFT639 product).
December 22, 2005: The parts for the
starter kit have arrived! Look for a kit soon in our Ebay
store! More documentation added for additional channel
December 14, 2005: The Command Set for
the initial release is complete on the Protocol Page. The
Ebay Store is ready to take your order for a Serial
More commands will be added to the protocol in the
near future with the 1.1. release.
Right now, only the programmed chip itself is for sale
in the Ebay Store. Look for a starter kit in a couple of
December 10, 2005: Started filling in
the Command Set in the Protocol Page.
Check it out to get an idea of how to talk to the
Wombat, and how easy it is to get started using only
The site is now also generated using a Perl Script
which creates each page by filling in a template from a
December 8, 2005: Added documentation
and Protocol pages, a contact us page
The documentation and protocol pages are preliminary
and incomplete. But they should give you some idea of
what you can expect from the Wombat.
December 7, 2005: On track for release,
New Ugly Web Site.
The Serial Wombat is on track for release on December
15th, 2005. See the Overview and Documentation sections
for details of what to expect from the Wombat's premiere.
This web site has been overhauled. It is no longer
created by one of those "Easy Website with no
coding" type programs. Unfortunately, I'm much more
of an embedded-systems programming guy than a web
programming guy. So the website is ugly.
On the bright side, I am a decent programmer in Perl,
so I'll be able to use this format to Auto-Generate pages
based on the Wombat's documentation, assuring that the
documentation on the web and in the documents always