Projects
Interface for the Seiko Datagraph UC-2001
digital wristwatch

In 1984, Seiko released the Datagraph wristwatch system,
consisting of the UC-2001 wristwatch and the UC-2301
interface for the Apple-II computer (via the gameport).
You will find lots of useful info about the datagraph,
the UC-2301 interface and the Apple-II here.
Unfortunately, the Apple-II is nowadays rather hard to find.
Wouldn't it be great to be able to upload data to the
watch from a modern PC, PDA or Mac?
Because I am planning to build my own watch based on
the UC-2000/2001 (see here), I want to have a way to
link this watch to my PC. And this interface seems to
be the most elegant way to do it.

Thanks to Tom Owad for providing me with a lot of useful
information about the interface.

It is quite simple to connect the UC-2301 (intended
for the Apple II gameport) to a standard RS232:

A RS232 interface is simple and allows connection
to many current computers, like PCs, PDAs or Macs.
A PC or Mac without RS232 can be equipped with
one using an easy to obtain USB->RS232 adaptor.


Update 2008: I finally found the time to tinker with the watch again.
Unfortunately, after a few years, the batteries in the UC-2301 had
died and leaked badly. I decided to remove the thoroughly corroded
battery holder and put a USB->RS232 adaptor in the vacant space,
using the 5V USB power from the adaptor to also operate the UC-2301.
I soldered 3 wires to the pads of the 3.5mm stereo jack and ran them under
the UC-2301 PCB to the space previously occupied by the battery holder.



I took a cheap USB->RS232 adaptor and removed the case and DSUB connector,
leaving only the small adaptor board with the USB cable attached.
Then I soldered the UC-2301-RS232 interface circuitry directly to it,
using a SOT23 SMD transistor (BC846C) and two 0805 SMD resistors (10k).



Connect all the wires, make a tight fit hole for the USB cable, done:


I made a simple Win32 PC (.NET C#) program that talks to the
UC-2001 watch using the modified interface.
It is a small program that simulates most of the UC-2100 keys, e.g.
for contrast, Memo entry and Calculator mode, and also allows to
download the 2 KBytes binary data stored in the watch and
upload 2 KBytes of binary data to the watch as data or program.
Here is a screenshot:

A zip archive containing the UC-2200 scheduler program and
the 4 games from the UC-2200 application ROM pack can be downloaded here.

A zip archive containing the MS Visual Studio 2005 solution with all source files
and the Win32 executable (requires .NET Framework 2.0) can be downloaded here.

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