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About BMOW

Big Mess o’ Wires is an electronics blog and e-commerce store for hobbyists and enthusiasts, run by Steve Chamberlin. Need some accessories for your Apple II, Lisa, or vintage Macintosh? Looking for info on microcontrollers or custom embedded hardware development? Enjoy tinkering with a soldering iron and vintage electronics? If so, you’re in the right place. You might even learn something about life in the maker business too.

Here you’ll find my custom CPU designs and related computer builds. You’ll also find occasional equipment reviews of oscilloscopes, logic analyzers, debugging tools, and other goodies. Thanks to many years of tinkering, I’ve become fairly skilled at working with various microcontrollers, designing custom circuit boards, and manufacturing my designs. Along the way I also got involved with vintage Apple computers, and have become something of an expert in a few niche areas surrounding Apple II and Macintosh disks and ROMs. Eventually I combined these passions, and now sell custom retro-computing hardware in the BMOW store.

Back in early 1980’s, I lived and breathed the world of the Apple II, Atari 800, Commodore 64, and their brethren. I could PEEK and POKE those machines like nobody’s business, and I spent countless hours writing programs, playing games, or just fiddling around. In contrast to today’s PCs, the computers of that era were inviting to tinkerers, with a comparatively simple hardware design and a BASIC prompt at boot-up.

As a computer engineering major in college, I learned the details of digital logic design. I used Texas Instruments’ big yellow TTL data book to help build everything from an LED blinker to a simple video game. I even built a rudimentary computer on a prototyping kit built into a suitcase: MIT’s infamous “Nerd Kit”. But after graduation it was all torn down, I went on to a career in software and video games, and my enthusiasm for electronics was forgotten.

Decades later I was finally able to explore my hardware passions again, and document the adventure here.


Big Mess o’ Wires

Why not “Big Mess of Wires”? What happened to the letter F? It just sounds better this way.


33 Comments so far

  1. […] (this is the part were more than half of you think I’m crazy, nerdy, or both) In a nutshell, it’s a home made CPU. Personally I think it’s fricking awesome. […]

  2. bryan l - May 28th, 2009 6:14 am

    I am amazed at what you have been able to accomplish with just a few wires and posts (and other assorted bits). This kind of thing just blows me away because I know the difficulty and frustration projects like this can bring. Bravo!!

    P.S. My cat would have a field day with that thing, but I wouldn’t let any cats near it….lol!

  3. The Real Adam – Shippin’ ain’t easy - May 29th, 2009 7:53 pm

    […] because you can: living frugally, JavaScript pixel art and hand-built microprocessors. Also, C as a functional language is nicer to think about than I’d first thought. If you ever […]

  4. ShinWarrior - November 8th, 2009 9:24 pm

    Beautiful work.
    I really admire what you have done. I am surprised you didnt have connection(continuity) problems.
    Thank you for sharing this with the world !

  5. Ahmad Mushtaq - February 23rd, 2010 3:39 am

    I’m motivated and thinking to do it by myself. But first I need to learn those logic gates stuff. Anyways… Thanks for sharing this with the world.

  6. Gregg C Levine - June 11th, 2010 8:02 pm

    Steve, you’ve seen me say this before, but that’s how I got started. I practically wore out an unsuspecting Apple II doing all of those things with it.

    Come to think of it, the same thing happened to a series of IBMPC compatible jobs before I ended up at this end.

    I’m still interested in how the machines think (or seem to be thinking).

  7. JB Autric - May 18th, 2011 9:54 am

    Nice wire wrapping job ! who knows now what is wrapping ?

  8. Peter - July 24th, 2011 2:03 am

    Steve, can only hook on to the comments before.
    GREAT jobs done here !
    Thank you for sharing and spending your time.

  9. Chuck Duppong - December 6th, 2013 9:35 am


    This is simply awesome! My brother and I both cut our teeth on 6502 machines.

    In my first job, I used to troubleshoot and repair big custom wire-wrap boards like yours. A lot of people don’t understand that when done right, wire-wrapped connections were/are very solid and reliable. I actually enjoyed doing it, and built a parallel port printer selector switch box for work (which became known as Megatron’s Brain).

    I actually used FORTH to debug and troubleshoot the wire-wrap boards. FORTH was actually easy for me, and I got quite good at it.

    Thanks for posting all this. It’s fascinating to see people actually do what I only talked about doing “some day”.


  10. RAM - December 14th, 2013 7:06 pm

    Howdy I am so thrilled I found your weblog, I really
    found you by error, while I was researching on Askjeeve for
    something else, Anyways I am here now and would just like to say cheers for a remarkable post and a all
    round thrilling blog (I also love the theme/design), I don’t
    have time to look over it all at the moment but I have saved it and also added in your
    RSS feeds, so when I have time I will be back to read a great deal more,
    Please do keep up the great work.

  11. Luca Severini - January 25th, 2014 9:48 am


    Your drive emulator for the old Macintosh looks really impressive. Congratulations!
    I’d like to buy one asap for my old Macs (Plus, SE/30 IIci).
    Perhaps my mistake but reading your blog I didn’t understand exactly how you sell them.
    On Ebay? Under what name?
    Thank you so much!

    Best regards,


  12. Steve Chamberlin - January 25th, 2014 5:47 pm

    You can place orders from the Floppy Emu main page, though it’s currently sold out.

  13. aris - March 9th, 2014 2:15 am

    I really wish you also had a mailing list for your new posts as I do not use RSS. Maybe try feedburner or mailchimp? I really like to read about you fab adventures as I am contemplating having something of my own manufactured too.

    Best of luck!

  14. Steve Chamberlin - March 9th, 2014 8:20 am

    Thanks! You can subscribe via Feedly- there’s a link in the upper-right corner of the page.

  15. aris - March 9th, 2014 10:28 am

    OK Steve, did that.

    Had seen the option before I commented. Unfortunately, now feedly has my email address instead of you. IMHO you should really be making it a priority to be capturing our consensually supplied email addresses as an email list is a very powerful tool. Especially when you:
    A. sell products
    B. sell products that are so specific

    Regardless, I still like your blog 🙂

  16. Steve Chamberlin - March 9th, 2014 1:21 pm

    Fair enough – I never really thought about it to be honest. I do get your email address if you choose to enter it when commenting (WordPress records it), but there’s nothing like a mailing list, and people who don’t leave comments are invisible. Everyone seems to think Feedburner is going to be discontinued any day now, so I intentionally don’t use it. I’ll look at some other options.

  17. Todd S. - June 7th, 2014 11:06 am

    Your site is an inspiration for us all, thank you for making it available. Your projects should be included in Computer Science departments.

  18. Renaud - January 2nd, 2016 3:20 pm

    Hi to all,
    First of all, happy new year. May all your wishes come true for the new year !!

    After having received the missing chain from the new world and Classic Mac, I can’t succeed to enter in HD mode. If someone knows, that would be so perfect !
    Thanks in advance for whoever helping me.

    Kind regards,
    Renaud F.

  19. Jonah - January 23rd, 2016 9:09 am

    Hello Steve just wanted to say i am extremely happy with your workmanship you are a genius. just wanted to know how can i put photos on the emu like Steve Jobs did in the unveiling of the macintosh video your help would be very much appreciated please get back to me on my email address thank you

    Impeccable packaging and delivery all the way to the UK

    kind regards Jonah Ripley

  20. Achraf Hussein - August 5th, 2016 1:15 pm

    Greetings Steve,

    I’m looking to buy the bundle kit right now for my dad who’s abroad right now. I have a friend who’s traveling tomorrow night and will take it with him. Can you do over night shipping? Please contact me asap on 201 668 9813. I live in Elizabeth NJ. Where are you located?!

  21. Steve - August 5th, 2016 7:51 pm

    I’m unable to offer any expedited shipping options, sorry. Normal orders ship 1-3 days after order and go by Priority Mail within the USA.

  22. Claudio De Souza - September 17th, 2016 11:32 am

    Hi Steve, I have an apple IIc and would like to know what\’s the difference from the Floppy Emu Model A to the Floppy Emu Model B for my system.
    I am guessing the model B is compatible with more machines, but I just have an apple IIc, is that correct? or there are more important differences.

  23. WWinter - May 25th, 2017 9:53 am


    Any plans for another batch of Floppy Emu boards? I’d purchase immediately.


  24. Steve - May 25th, 2017 9:58 am

    Yes, see the note on the page, more should be available next week.

  25. WWinter - May 25th, 2017 10:03 am

    Fantastic! I guess I’m just in time. Will be buying as soon as I see it available. Thanks!

  26. HE LAN - September 26th, 2017 5:10 am

    Really cool works!!
    I built a desktop printer (some kind of 3D printer)which can print transistor circuits with organic transistor/oxide transistor(not only transistor circuits actually, but also solar cells, OLEDs, various sensors etc. and yes I am an entrepreneur), I think democralizing the technology and enabling everyone to printer their own computer at home is something really worth-doing. Any chance of collabrating with you?

  27. Gregory Schroeder - July 25th, 2018 4:48 am

    Steve, Are you the Chamberlin from IL that I known. I didn’t knew you were an apple ii user.
    Are you making a batch of disk emulators soon?

    To the guy with the 3D printer, how much would be to get one that prints solar cell?

  28. Keith - October 26th, 2018 12:10 am

    Thank you for the awesome stepping out of the commercial aspect of being a hobbyist. How ever. I realize life is busy. But where is the update on what you’ve been doing Steve? My first name is Keith. But a coworker used to call me Steve. I got used to it. Until some one corrected the situation. With my proper first name. Please. When you have a few minutes to update your fans. Thank you in advance.

  29. James - March 18th, 2020 3:04 pm


    I have a question.

    I bought a floppy emu. I need the Macintosh firmware. I have the links. But Can I just drag and drop it onto my sd card?

    Does it have to be a disk image?

    I’m planning on going to the library tomorrow with my MacBook Pro and an sd card reader?

    Just wondered how exactly to install the firmware?

  30. John - December 3rd, 2020 3:52 pm

    Thank you for your blog and for the products you are making – I found you on hackernews and although I am not an Apple collector/enthusiast I *do* run many old Sun/SGI/CBM machines in my lab – it makes me happy to see equipment and projects like this.

    I have no idea if you have any use for a free-forever account, but if you do, just email me and I will set one up for you.

    Thanks again.

  31. Ruffs - June 6th, 2021 4:36 pm

    Steve, this is great! Just ordered Mac ROM-inator II – and the year is 2021!

    I hope you keep at it, and look forward to the Mac ROM-inator III (three) one day, when some new idea pops up in your head or you have some great new idea!

    Thanks so much!

  32. Chris Thomas - June 16th, 2021 12:28 pm

    It’s nice to see there’s a fellow fan and tinkerer of Apple ][ still around! I have plans to buy the floppy emu in a couple weeks after I get back from vacation to back up my old work! If not for this series of computer, I would not be the same person who I am today. You’re right – there’s just something about them that “invites” one to tinker with it. I was programming in Applesoft BASIC at 5 years old.

    How difficult would it be to get the Apple ][ Joystick to work on a modern PC? That’s one huge piece I have been missing when it comes to using any of the emulators out there. Not being able to use the hardware just doesn’t have the same “feel”.

    P.S. I don’t know if anyone else has noticed the font in use in this comment box. What a very nice t0uch.

  33. falecore - August 6th, 2022 11:45 pm

    The Pirate ROM and Floppy EMU are total game changers! Thank you for such incredible products! We had a blast putting it together and hooking it up to the Mac SE, SE/30 and Classic. We didn’t even realize the goodies it came with!

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