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New Project Ideas


It’s high time for a new project here at BMOW. These days I spend so much time on Floppy Emu, it’s hard to squeeze in anything else! A new project would help stir things up, and get the creative juices flowing. Here are some ideas I’ve been kicking around:

Electric Scribbling Machine – I described this one in yesterday’s post. It’s a tripod with colored pens for legs, and a motor that makes it move, drawing tracks on the paper beneath it as it goes. Yesterday’s post described a “vibrabot” design using an offset weight on the motor shaft, which randomly jiggles the machine and creates interesting erratic drawings. I’ve since been working on an alternate design in which the motor is used directly as one of the legs, which spins the whole machine in rapid circles, and creates elegant looping drawings somewhat reminiscent of a Spirograph.

USB Keyboard/Mouse Adapter for Vintage Macintosh – Classic Macintosh computers like the Mac SE and Mac II series used input devices based on ADB – the Apple Desktop Bus. The Mac Plus and Mac 128K/512K were more primitive, and used custom protocols for keyboard and mouse rather than any bus-based system. Both systems are fairly well documented, and I have some experience with them already. Using a modern microcontroller, it shouldn’t be too difficult to build an adapter that functions as a USB host for a modern keyboard and mouse, and translates the input data to ADB or the Mac Plus protocol.

Weather Logging Station – A few years ago I designed the Backwoods Logger, an ultra-tiny portable weather station. I envisioned it mainly as a graphing altimeter for people going on mountain hikes. After many discussions with interested people, it became clear that most people didn’t care about portability, or about having graphing functions or even a screen. What they wanted was a stationary module that could take regular temperature, pressure, and maybe humidity readings, and save a history of weeks or months of data. There are already a few designs like this, but maybe they’re too intimidating or their feature set isn’t quite right, because I still get occasional emails from people asking for something like this.

Nibbler KitNibbler is a 4-bit CPU that I designed entirely using basic 7400-series logic elements. It was a one-off project for my own entertainment. William Buchholz later designed a nice Nibbler PCB for his hacker group, which got me thinking that something more polished would be nice. My web stats say the Nibbler pages are some of the most popular content on this site, so maybe there would be enough interest to justify a Nibbler kit? My only fear in offering a kit for something this complex is the potential support headaches. It might make more sense to offer finished Nibblers instead of kits, though that would take some of the fun out of it.

Electric Bow Tie 2.0 – As with the Backwoods Logger, I think I misjudged popular interest when I designed the Electric Bow Tie Kit. It’s fun to have neckwear that blinks and beeps, but mostly people don’t seem interested in assembling a kit – they just want something kitschy they can wear to a special event and get some laughs. I can say from personal experience that the blinking effect is fun, but the beeping effect starts to grate on your sanity after about 60 seconds. Electric Bow Tie 2.0 would probably drop the sound effects, but add many more LEDs controlled by a microcontroller, enabling all kinds of entertaining and annoying patterns like chase lights and starbursts. I’d also try to replace the 9V battery with one or two smaller CR2032 batteries to reduce weight.

Read 17 comments and join the conversation 

17 Comments so far

  1. Mark - March 3rd, 2016 9:15 pm

    I vote for the nibbler.

    Thanks for all your great posts. I check your site regularly for new posts.

  2. Steve - March 3rd, 2016 9:50 pm

    Do you think a Nibbler kit would be of more interest to people, or a finished Nibbler computer?

  3. Mark - March 3rd, 2016 10:46 pm

    I think a kit would be more interresting. The build would be half of the fun.

    I do get your point about support though. Maybe you could set up a simple forum where other people could chip in and offer assistance as well?

  4. Eric - March 4th, 2016 5:12 am

    I like the ADB adapter, weather station, and nibbler kit in no particular order. I think the ADB adapter would be particularly useful. I would like to do the weather station kit with some students. Could be fun to build upon the platform. Include other environmental monitoring sensors like water or air quality.

  5. Trygve Laugstøl - March 4th, 2016 6:29 am

    I also vote for the nibbler as an unassembled kit. It would be nice if it would include many test points so that it can be inspected for searching faults. Something easier to program than EEPROM chips would be nice for speed of development.

  6. Steve - March 4th, 2016 7:45 am

    I hear you on the difficulty of programming the EEPROM. Those chips can be reprogrammed from within the system, and my 68 Katy project did that. But Nibbler doesn’t have a serial port or other external communication link, nor enough RAM or other computing capabilities to do that. And adding all that stuff would spoil the simplicity that makes Nibbler appealing, I think. Even front-panel switches would require some major changes, as Nibbler can’t currently execute instructions stored in RAM! I’ll give this some more thought.

  7. Trygve Laugstøl - March 4th, 2016 7:59 am

    Hm, so what about making a board that contains SRAM that can be programmed through a serial port? Being able to inspect the ram with openocd would be awesome and useful for many retro projects. I’ve been looking into making something like that for an old Z80 board I’ll never be able to use without an easier way to program than using EPROMs.

  8. MikeG - March 4th, 2016 8:19 am

    I previously assembled the Nibbler with and without using William’s board which was a lot of fun. An assembled version would be less exciting. I think in either case it is important that it has some expansion capabilities. Built-in programmer would be neat, though not essential. Some sort of i/o port will actually make the board useful (as opposed to just fun to build). Perhaps just a data/address bus connector for simple parallel i/o.
    More RAM will only be useful if an indirect memory addressing mode is added to allow arrays or pointers. As it stands, the Nibbler has more RAM than a real program can address. There is no need to store instructions in RAM (and that would be difficult given that RAM is 4 bit and instructions are 8/16 bit). Programming switches can work with EEPROM though programming with switches is going to be more painful that taking the chip out.
    I don’t know if it is possible to add indirect addressing without adding too much complexity (additional commands, address registers etc). I think it is more important to keep the design simple.

  9. Wesley - March 4th, 2016 1:05 pm

    I love the idea of an ADB adapter…bonus points if it can do both PS/2 and USB keyboards/mice. I’ve got a pair of the old Belkin Mac adapters…possibly build in a simple DB15 to HD15 VGA adapter too? Basically clone the Belkin adapter, which is mostly impossible to find. One catch though…watch out for the old ADB stuff. I gather there is something different about the early implementations, and apparently the Belkin adapter doesn’t play perfectly nice with it. On an old Mac LC, the adapter won’t work with *both* keyboard and mouse connected. However, if I loop the ADB through to the other adapter I have, I can use one for the keyboard, and one of the mouse, and it works…weird. Just something to keep in mind if you pursue that route…

  10. Fred - March 11th, 2016 9:43 am

    I jumped on your site looking desperatly for a way to replace the old floppy drive of my Roland D-20 music keyboard (used to save songs and sounds). Sadly, it’s not a standard 34 pin 720k floppy drive, but a totally different model.
    By giving a look at the service manual for this synthesizer (available here: ), and trying to figure out what kind of floppy drive “standard” this could be, I noticed on page 13 that the drive used “two-phase drive pulses to step motor for head shift”. The PIN description is very similar to apple DISK II interface cable, but I have no skills to chek this out…
    I don’t know if you have acces to that kind of synthesizer to give it a try, but your floppy-emu device would look great on those vintage keyboards (and there’s probably a market in vintage synths: floppy drives, extension boards, etc. 😉

  11. cb88 - March 11th, 2016 10:03 am

    The ADB adapter already exists… sort of.
    and … he doesn’t see large runs of kits like you do though.

    Personally I’d like to see a 5.25 and 8in Floppy to USB adapter … the only one I know of is read only :/ <- like this but with read/write support. Mounting known file systems as mass storage.

    Mainly want one for myself to make it easier to get files on and off my AT&T Unix PC.

    After that, a kit to make a PDP-8 using modern transistors and routed PCBs etc… would be a little pricey (around 1000-1500 transistors) but a ton of fun to put together… paper tape punch/reader. In theory it should be possible to keep the kit cost under $150-200 unless there are problems finding workable transistors in the right price bracket. Actually this is what I think "Heathkit" should be doing…

  12. Keith Kaisershot - March 11th, 2016 10:51 am

    I personally would *love* a USB->ADB/Plus converter board that works with my USB KVM switch. Having to keep three or four keyboards and mice strewn around my desk makes my work area pretty cramped and cluttered, not to mention that my primary USB keyboard is in much better shape than my Apple ones.

    Bonus points: could you also rig up a converter to the Lisa keyboard protocol? We both know my Lisa keyboard is in some pretty bad shape. 😉

  13. Steve - March 11th, 2016 11:11 am

    Yes, bbraun has done some great work on the keyboard/mouse adapter idea, and I have one of his prototypes. I’m not sure he’s interested in pursuing it, though. He ran into some trouble with the reliability of USB initialization that I don’t think he was ever able to solve. I was imagining something a little less complex (and no PS2 support), but his solution would be great if he decides to take it further.

  14. Keith Kaisershot - March 11th, 2016 11:23 am

    Yeah, I asked him a while back for one of them, but like most things he’s working on, he’s taking his time with it. 😛

  15. Jeff - March 16th, 2016 12:04 am

    My vote would be for a universal pre-ADB/ADB/PS2/USB adapter – kind of a mashup of bbraun’s stm32f0discovery-based Mac Keyboard Interface project mentioned above with Hasu’s Teensy-based ADB to USB keyboard converter ( and M0110 USB converter ( projects.

  16. Pascal (gfcwfzkm) - March 22nd, 2016 4:17 am

    Well, the most interesting project that i always check out is your nibbler Computer.
    A kit would be not bad. But maybe add two input-ports (like the output-boards) so a 4×4 Pad would fit would be awesome too… 😀

    For a homemade computer its also one of the simplest design (without using a finished CPU).

    I would love a nibbler kit with maybe bit more I/O (like four IN/OUT -Ports)…

  17. Peter - June 10th, 2016 10:34 am

    Perhaps this is a little too ambitious, but I’d love a modern day vintage mac replacement. Something I could buy that was hardware compatible with the various vintages of pre-OS X systems out there that would allow me to run vintage software but with modern amenities, like faster speed, USB, higher resolution video, etc., and, er, not the baggage of time causing hardware to fail.

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