How to reverse engineer Brother PED Memory Card/Slot to make adapter

It is going to be extremely difficult to convert from a USB memory stick format to a 42-pin card format. It is likely that some parallel memory interface is used, and USB is a serial format. It would require some microcontroller to achieve the task. You'll need a logic analyzer at a minimum to try to decipher things unless you are lucky and find some information online. The cost of a logic analyzer and prototyping up a solution with a microcontroller will exceed the cost of the blank 4MB card many times.

shabaz good feedback and good things for me to consider.

Not sure if you are still interested in this, but I've recently taken a look at this and the Amazing or Magic Boxes are virtually identical with the exception of the firmware in the box. More to the point, they are cheap, and work well in a VM running WinXP using a USB to serial adapter such as the Tripp Lite usa-19hs, which comes with a data monitor built in.

The slot for the Brother card is an Amp 175758-1 connector, which is a 1mm pitch x 40 pin connector and an adapter can probably be made using a 40 pin 1mm pitch female connector soldered edgewise to a PCB that exposes the connections to a "normal" 40 pin socket. This would take the place of the memory card.

From there a Gotek possibly?

Just googled this question and very happy to see your answer just a month ago ️

My pleasure, here's (most of) a post that I made on Youtube as to how to create a work-around:

Is the issue that you are having Windows refusing to install the drive because it isn't "signed" by Microsoft? If so, drop down to #2 and install a virtual box on your PC (or Mac). The virtual box is nice for a couple of reasons, the first being that what happens over in the virtual box stays in the virtual box and won't mess up your main OS. Second, backing up your virtual box is as simple as making a copy of the "machine" (a file usually around 50GB or so) and using the most recent copy to restore your virtual box OS. 

Find yourself a cheap Magic Box/Amazing Box (they are the same hardware from what I can tell). And with luck you will get the card as well. But you're going to have a few issues:

1) Be sure that the cables are included. I've seen them for sale on eBay without the "wallwart" power supply. Be sure that it comes with it, but if the price is really good these can be replaced rather easily. The serial cable is most likely a null modem cable and the USB to serial adapter should be able to plug directly into the box without the cable. And there currently is an auction for a box that has a broken power connector. It probably will still work, but I would want the seller to lower the price to reflect the condition of the box.

2) The software for these devices is old and will not run on a modern 64-bit PC. Not a problem, go here and (legally) get Windows XP for free: https://www.makeuseof.com/tag/download-windows-xp-for-free-and-legally-straight-from-microsoft-si/ Follow their instructions for installing it to a virtual machine. I would caution you not to set up the Windows XP side to connect to the Internet since XP won't last long on the Internet these days... Remember what I said about the boxes looking the same? There's a good chance that either version of the software will work with either box. So download the software from the the boxes site.

3) New PCs don't have a serial port these days. The serial port issue can be solved by getting a cheap USB to serial converter. eBay has them for as low as $7.77 with free shipping. Be sure that the driver supports Windows XP and earlier. The reason for this is because you are going to need to run the software in the virtual box that you have Windows XP setup in.

And remember, you still have to find a card, specifically a "Brother" card, for it.

I'm a retired Controls Engineer and we face this sort of problem (or much worse) as part of the job. Companies aren't going to chuck out their machinery just because Microsoft upgraded Windows. So we have to set up PCs that match the environment that the software was written for (all the while dodging the guys from IT that want to tell us what software to use). Did I mention that I'm retired? Some one else's problem from here on out. :)

I have a PE-180D that I guess that it's time to pull the cover off of and see if I can add something like a Gotek and bypass all of this silliness.

Hi - I recently got my hand on a PE-100 and am in the same boat. Basically I would just like to transfer designs to the machine that I am making with inkscape / inkstitch, but super annoying how they built in this bottleneck of proprietariness with these memory cards.

Something like a Gotek would seem like a great idea as well.

Any luck on any of these fronts?
Very interested + gladly cheering you on!

There is some discussion on the old Brother card formats here which may be of interest:

https://www.eevblog.com/forum/reviews/brother-(possibly-also-bernina)-embroidery-machine-memory-cards/