This page documents what you need to do to actually build one. Do not fear, I know several people with mediocre soldering skills who’ve done it (I count myself as one of those).

Bill of materials

This is the physical stuff you’ll need.

  • One or more floppy disk drives. Both 3.5” and 5.25” work. One FluxEngine will even run both drives (but not at the same time, obviously). You’ll also need the appropriate cabling to plug the drives into a PC.

  • A Cypress PSoC5LP CY8CKIT-059 development board, which is a decently fast ARM core wrapped around a CLDC/FPGA soft logic device. You can get one directly from Cypress via the link above for $10, but shipping can be extortionate depending where you are. You can also find them on eBay or Amazon for about $20.

  • Either a 17-way header pin strip or a 34-way IDC motherboard connector (or one of the other myriad compatible connectors; there’s a billion).

  • A suitable power supply. 3.5” floppy drives use 5V at about an amp (usually less) — sadly, too much to power from USB. 5.25” floppy drives also require 12V. An old but decent quality PC power supply is ideal, as it’ll frequently come with the right connectors.

  • a Windows machine to run the Cypress SDK on. (The FluxEngine client software itself will run on Linux, Windows, and OSX, but you have to build the firmware on Windows.)

  • Basic soldering ability.

  • (Optional) Some kind of box to put it in. I found an old twin 5.25” Hewlett Packard drive enclosure and ripped all the SCSI guts out; this not only provides a good, solid box to house both my 3.5” and 5.25” drives in, but also contains an ideal power supply too. Bonus!

Assembly instructions

All you need to do is attach your chosen connector to the board. You’ll need to make sure that pin 2 on the cable is connected to pin 2.7 on the board, and pin 34 to pin 1.7 on the board (and of course all the ones in between). Apart from grounding the board (see below), this is literally all there is to it.

The pads are small, but soldering them isn’t too bad with a needle-nosed soldering iron tip.

If you’re using a connector

Line it up like this.

closeup of the board with connector attached

Note the following:

  • You’re looking at the back of the board (the side without the big square chips). The connector sticks out of the front.

  • The notch on the connector goes at the top.

  • The top row of pins on the connector overhang the edge of the board: they remain unconnected.

Also, be aware that some floppy disk cables don’t have a projection on the motherboard end to fit into that notch, and so will plug in either way round. That’s fine, but some of these get round this by missing a hole for pin 5. That way they’ll only plug into the connector one way round, because the connector is missing a pin. If you have one of these cables (I do), you’ll need to use a pair of needle-nosed pliers to pull pin 5 out of the connector.

If you’re using header pins

Line it up like this.

closeup of the board with connector attached

You’re now looking at the top of the board.

(It’s also possible to put the pins on the bottom of the board, or to use a row of header sockets allowing you to plug the board directly onto the floppy disk drive; for simplicity I’m leaving that as an exercise for the reader.)


You also need to solder a wire between a handy GND pin on the board and connect it to ground on the drive. Because the board is powered by USB and the drive by your external power supply, they can be at different potentials, and they need to be tied together.

If you’re using a connector, the simplest thing to do is to bend up one of the unconnected pins and solder a short piece of wire to a GND pin on the board. Alternatively you’ll need to splice it into your drive’s power supply cable somehow. (The black one.)

Building the firmware

On your Windows machine, install the Cypress SDK and CY8CKIT-059 BSP. This is a frustratingly long process and there are a lot of moving parts; you need to register. You want the file from the above site marked ‘Download CY8CKIT-059 Kit Setup (Kit Design Files, Creator, Programmer, Documentation, Examples)’. I’m not linking to it in case the URL changes when they update it.

Once this is done, I’d strongly recommend working through the initial tutorial and making the LED on your board flash. It’ll tell you where all the controls are and how to program the board. Remember that the big end of the board plugs into your computer for programming.

When you’re ready, open the FluxEngine.cydsn/FluxEngine.cywrk workspace, pick ‘Program’ from the menu, and the firmware should compile and be programmed onto your board.

Note: If programming doesn’t work and you get a strange dialogue box asking about port acquisition, then this is because the device isn’t responding to the programmer. This is normal but annoying. You should see the device in the dialogue. Select it and press the ‘Port Acquire’ button. The device should reset and an extra item will appear in the dialogue; select this and press OK.

If acquiring the port doesn’t work, resulting in the IDE hanging for 45 seconds and then producing a meaningless error message, you need to reset the programmer (the little board hanging off the side of the bigger board). You’ll see that the light on the programmer is pulsing slowly in a breathing pattern. Press and hold the little button near the light for five seconds until the light stays solidly on. Now you should be able to acquire the port and proceed normally.

Building the client

The client software is where the intelligence, such as it is, is. It’s pretty generic libusb stuff and should build and run on Windows, Linux and OSX as well, although on Windows I’ve only ever used it with Cygwin. You’ll need the sqlite3, meson and ninja packages (which should be easy to come by in your distribution). Just do make and it should build.

If it doesn’t build, please get in touch.

Next steps

The board’s now assembled and programmed. Plug it into your drive, strip the plastic off the little USB connector and plug that into your computer, and you’re ready to start using it.

I do make updates to the firmware whenever necessary, so you may need to reprogram it at intervals; you may want to take this into account if you build a case for it. I have a USB extension cable plugged onto the programmer port, which trails out the side of my drive enclosure. This works fine.

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