Most people who deal with Commodore hardware will also like the term "ZoomFloppy". I've been using this hardware for some time, too, but I've also been bothered for so long that the board is extremely large and unwieldy. The ZoomFloppy is also delivered as a naked board, without any case. This made me shrink the ZoomFloppy.


The ZoomFloppy is a very popular piece of hardware. This board allows the connection of old Commodore peripherals to the PC. The board offers not only a connection for the serial floppies, like the 1541 or 1571, but can also operate the floppies of the CBM series via the IEEE-488 socket. There is also a parallel port as known from SpeedDOS. The connection to the PC is established via a USB interface. The corresponding software openCBM is available as Open Source for many operating systems. The source code is also available.


ZoomFloppy von Retro Innovations


Personally I rarely use the parallel port and even less the IEEE-488 port on the PC. And I've often been disturbed by this unwieldy board, especially since I always have to be careful not to accidentally short-circuit the contacts because they are all open. So I thought about how I could get the ZoomFloppy small.

The first thing I needed was a circuit diagram. I didn't find a complete schematic on the internet, but there are always parts of single sections on the internet. Also a part of the description can be found in the source code package of openCBM. So it was quite easy to combine the whole sections. The resulting schematic was redrawn with KiCad.


Xoomfloppy Schaltplan


Of course the IEEE-488 in its original size was not possible on a much smaller board, also the parallel port had to give way. I then had a board made in Asia. However, I was not really satisfied with the result. In the beginning I only had a USB and the IEC socket integrated on the board, which still made the board quite big. So I tried to shrink the board more and more. Also all components should be placed on one side to facilitate the later assembly.

Then the question of a case arose. A small board is one thing, but it would still be as unprotected as the large ZoomFloppy board. So I searched the internet for a nice small case. The selection there is huge, but I didn't like many of them. Then I got the idea, if there is not a nice USB stick case. But also this was not so easy. I didn't want to drill, it should have an appealing design and of course everything had to fit into it.

In the end I found a suitable case at the company Richard Wöhr GmbH. The good thing was that you also delivered to end customers. Less practical was the minimum order value and that the individual price of a case was also not very attractive. I decided for a case from the series GH02SG001 in transparent.


3D Modell des USB Stick Gehäuses


The advantage of the housing was that it is screwable and has a cable outlet. Additionally there is a protective cap for the USB plug. At the same time it turned out that my idea developed into a collective order in The demand was so high that I had to order 100 of these cases. But that made the price per piece in a very attractive region.

Now only the circuit board had to be optimized accordingly.


Verschiedene Versionen der XoomFloppy


I experimented with a variety of different components in order to optimize the routing of the tracks, but also to simplify the subsequent soldering process. And since all components should be on one side, these 3 points were not so easy to reconcile. The whole thing was like a little puzzle game. But in the end I had developed a version, which fit these criteria and what was even more important, also into the case.


XoomFloppy PCBs im Panel


The picture shows the final version of the board. Whereby here 6 pieces of it are summarized in a panel. 

Feritg assembled it looks like this:


XoomFloppy PCB Bestückt


At some point I decided to at least lead out the parallel interface. These are the upper 10 contacts next to each other on the picture. There you can solder a ribbon cable to connect it to the floppy.

The files for this project can be found in the download area. Questions or suggestions can be left in the comment area. 


Have fun with the replica. 


I still have some circuit boards left. This can be requested for a small contribution towards expenses: PCBs


Translated with


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Artifex's Avatar
Artifex replied the topic: #55 1 week 2 days ago
Hello, is there any chance of getting the files for this project? Download links disappeared during last couple of days. Thanks!
diwou's Avatar
diwou replied the topic: #56 1 week 1 day ago
Hello Artifex,

The download area is currently offline. But I offer the boards directly. PCBs
Anonymous's Avatar
Anonymous replied the topic: #57 1 week 51 minutes ago
Hello, Dirk.
Thanks for an answer, I have my board already done from times before but I didn't have time to complete it yet and now, the partlist and FW is not reachable.
diwou's Avatar
diwou replied the topic: #58 1 week 30 minutes ago
I'm in the process of completely rebuilding the download area. If you give me your eMail address via the contact form, I can send you the things before.

I will still need something, until the download area is ready.

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