Ploopy Open Source Trackball Keeps Rolling Along

We’ll be honest. When we first heard about a mouse, we weren’t convinced. The argument was that business people weren’t familiar with computers. That didn’t ring true since every business person in the last century had at least seen a typewriter keyboard, but most of them had never seen a mouse before the 1980s. The mouse has since become totally ubiquitous, so presumably, it was the right choice. However, if you are a serious touch typer, it is annoying to have to move your hands off the keyboard to a different location each time. There are several solutions for that, but the oldest one is probably the trackball. Ploopy is an open source trackball you can build yourself and it looks pretty capable.

While we aren’t wild about the name, Ploopy looks pretty good and is one of those projects that would have been very difficult ten years ago. It requires two PC boards. Those used to be hard to get. It also requires some very customized plastic parts. Getting a handful of plastic parts made used to be hard, too. But now you probably have a 3D printer that is just begging for something to do.

Modern electronics also helps the design. An ATMega32U works as the processor and an optical sensor watches the ball for motion. Speaking of the ball, apparently, it is a common miniature snooker ball. The designer sells a kit of parts — or at least will sell them. However, the details provided for sourcing your own parts is among the best we’ve ever seen. Where some bill of material lists will say something like M3x12 flat countersunk machine screw, the Ploopy wiki has the following details:

  • M3
  • 0.5 mm thread pitch
  • Any length between 8 mm and 16 mm
  • 5.6 mm head diameter
  • 1.65 mm head height
  • 90-degree countersink angle

Short of providing an actual link to the McMaster catalog, we aren’t sure how much more than could specify. Well, they didn’t tell us what type of metal the screw should be but now we are just being nit picky.

The 3D shape of the enclosure looks great. They use threaded inserts to thread the holes, so that should be pretty durable. The resulting trackball looks totally professional. Granted, you probably could run down to the store and buy a nice trackball for a fraction of the cost of this — especially if you assign a value to your time. But still, there’s something to be said for building something you’ll use a lot and that’s hard to price.

Oddly enough, this isn’t the first time we’ve seen a billiard ball pressed into service like this. At least they are cheap and easy to obtain.

35 thoughts on “Ploopy Open Source Trackball Keeps Rolling Along

  1. They seem to only care about right handed people (aka people who can easily find trackballs) . And the way the circuit boards are laid out it doesn’t seem that you could make a left handed version with them.
    Now I know that lefties are at best 10% of the market, but a left handed only track ball is something that i cannot buy at all. If it was a leftie, I’d have my credit card out right now. Instead im here leaving disapointed comments.

      1. yes, cura has an option to mirror the print in any axis you want. Then, you just need to fix the circuit board in there upside down and tadaah! You’re done! Anyways this is quiet a cool project! I don’t think I would just copy this and make it myself, especially not the electronics, but it might be a nice project to build my own mouse someday :-)

    1. What a great opportunity!
      You can download the open-source files and mirror everything.
      You’ll be queen of the left handed people looking for a left-handed trackball.

    2. I’ll offer up the KeyMouse Track as an alternative. They offer preassembled units along with kits you can assemble. Both a bit pricey though you could get the piece parts and 3D print the housing yourself. The huge benefit (from my perspective) is that these are true “no reach” mouse & keyboard combinations, while also giving lefties and righties equal usability.×600.png

      1. I’ve used a trackball for a couple of years, I’m still not sure if it’s the way to go, but I don’t move my arm as much, and don’t need desk space to move a mouse.

        It would be nice if trackballs were cheaper and more varied, but tyat comes with more users. I found a 75cent trackball at a garage sale, and it was fine but I missed a scroll wheel, so I splurged on a $50 trackball.

        One thing, a trackball is great for testing computers where you might not have desk space.

  2. “Short of providing an actual link to the McMaster catalog, we aren’t sure how much more than could specify.”

    Actually, to be stickler, the proper way would be to list it by the relevant DIN or ISO norm (DIN 963, 964 or 965 in this case for instance). Unless specifically listed metric thread forms are coarse threads (0.5 for M3) by default so no need to list the pitch.

    So my BOM would normally read: X pcs DIN 965 M3x12-16

    That’s basically exactly the same information. Unless you care that you specify Ph or Pz crosscut drive screws specifically that’s all you need. It’s what most people will have easy access to anyway.

    The alternative would be DIN7991/ISO10642 with an internal hex or ISO14581 with a torx drive. They have exactly the same head shape. Anyone voluntary using straight slotted screws should be fitted for a white jacket with long sleeves that tie in the back imho)

    1. Because the user wants to spend $68 to find out for sure what an ISO14581 screw is? One really doesn’t know what is specified in the standard without having access to it, so why reference it when probably all the information he has about a part is documented on the mcmaster website. I think the best he could say is “this is what I bought and it worked” and it is left to you to draw your own conclusions about the compatibility of whatever you want to buy.

      1. You don’t need to buy the standard to find that info. Most vendors I can find that sell fasteners list the DIN and/or ISO norm. Even McMaster-Carr does! And if you really need to know the size (instead of just “Oh, a flat head countersunk screw”) again most suppliers have size drawings for the products to look it up.

      2. Somehow it seems my reply got eaten.. Try no. 2

        You don’t need to buy the norm documentation to find out what the screws are. Pretty much ANY vendor I can find that sells fasteners lists the ISO/DIN number for their products (McMaster-Carr too). So you could just google ISO14581 and have all the info you need. And if you really need to know the head dimensions they list those too. It’s really not any slower than having to check whether the screw you found has the correct head dimension (Hint, if it’s an M3 flat head countersunk machine screw it will be). In fact, if you need oddball screws you’ll have WAY more success finding it at a vendor for an affordable price if you know the DIN norm. And you can find that easily enough by clicking through the pictures in the catalogue/shop of expensive vendor.

        1. I guess that is my point, you are just using the ISO number as a meaningless keyword, it, in of itself, does not provide any information content to the normal person. It is just a string of letters and numbers that serve as a substitute for real knowledge and will only confuse the mouth breather at your local home despot. I think this is a shame on a basic level. I guess mcmaster carr might decide tomorrow that they will rearrange their website, descriptions, and their part numbers.

  3. I’d say the market can be much bigger. Using mouse or trackball is a simple task that can be learnt quickly. The benefit is that a mouse or a trackball on the left is much closer to where one keeps their left hand while typing. I recommend it.

  4. Something weird is happening. I don’t see the picture on this article. Comparing the source with one from another article there is a trailing after the picture-tag. It is my Firefox messing up things or is the HTML actually wrong? Looking at “inspect element” i see some CSS on the picture that should not be there. What??
    FF 60.9.0 ESR

    1. My Logitech M570’s (I have 3 of them) work great and cost under $30. Even the high-end trackballs are under $100. And the MS Trackball Explorer, considered by some to be the best trackball ever made (I semi agree) is available as NOS for $100. You expect me to pay $200 and I have to put it together?

        1. Just one problem with the MS Trackball Optical, the steel ball bearing points. If you want the finger or thumb versions to work for a long time you have to be absolutely fastidious about cleaning. Wash your hands before using the computer. When you feel the least little bit of drag on the ball, pop it out and wipe off the three steel balls.

          If you just use and abuse it like any other trackball, you’ll wear flat spots on those steel balls and the trackball will drop down and drag in the plastic socket.

          There used to be people who would rehab these by somehow removing the steel balls and replacing them with silicon carbide ones, like Logitech and others use.

          If someone would clone both MSTBO’s with a silicon carbide upgrade, that would be very nice.

          Around the time Microsoft discontinued these, there were a ton of returned thumb ones cleared out on eBay. The problem was the transistor for the tracking LED was in a position where during assembly it could get hit and crack one or two of the solder joints. I assume how they passed QA was the assemblers had a USB power port and would plug them in and see the dimmer and decorative “I’m Optical!” red LED light up then send it on down the line.

          Easy to fix, open the case and hit all three legs of the through hole transistor to fix any broken solder, then bend the transistor towards the middle a little.

          1. I still have a bunch of logitec optical trackballs, the ones that came with the little hoozie that would let you plug them into a ps/2 or s usb connector. The computer geeks had them for $9 a pop like 15 years ago and I bought a bunch of them, and they just do not die. You pull the ball out once in a while and clean the optical pick up with a q tip and wipe the grub off the teflon and you are good to go. The things are indestructible.

            When their kit gets to the sub $10 level, I am all in.

  5. Ah yes, I remember the Microsoft Trackball Explorer. Say what you will about MS business and project practices, but they make some good hardware. I nearly cried when mine bit the dust… and replacements were $300+ on ebay. I got noticeably worse at shooters when I had to go back to a mouse.

    1. Same here, and I’ve been watching this project because this thing is a dead ringer for it! It was the only trackball I really ever liked and was comfortable using for extended periods. Those Logitech thumbballs just make my hand hurt!

      I got more than 10 years out of it, though. I think I picked it up in 1999 and it outlived my PowerMac G4, which I stopped using in 2009. I found it in a box a couple years back and plugged it in, but couldn’t get it to work.

    2. You can get it refurbished!

      I own 2 of them (one for work, one for home), and I was panicking when my work one started to get flaky. I sent it to this guy, and I am a VERY satisfied customer:

      The home one is starting to be a bit flaky lately, I’ll probably send it in too.

      That being said, it is interesting to see this project as a possible replacement. Given how popular the MS trackball is amongst those that have used it, it’s always surprised me that someone doesn’t make an equivalent.

  6. I’ve still got me olde faithful logitech that I get out everytime I blow out my back and need to lie in that one position in bed. But I do yearn for trackballs in some situations. Mostly when the touchpad on whatever machine I happen to have picked up sucks, but I don’t have mouse surface/space. I only get along with about 2 out of 7 touchpads. I miss those side clip-on trackballs most rather than the desk dwellers. Though I’d also think about a desktop keyboard with one built into the top corner. I’d also go for one of those pistol grip or wii nunchuck handle type ones with a trackball on top. Mostly I prefer a mouse when there’s room though. I needed something “mid air” the other week and ended up using an inverted mouse with a post it note stuck on my thumb LOL.

  7. This needs a thumb ball version, preferably a perfect clone of the Microsoft Trackball Optical 1.0, but with silicon carbide bearing balls instead of the cheap steel Microsoft uses that required being fastidiously cleaned to keep them from wearing down.

    Some cheaparse penny pincher at MS wouldn’t spend about 10 cents more per unit, which would’ve been nothing at the price those originally sold for.

  8. Two points. The GitHub link mentions a snooker ball and not a billiard ball. They are different creatures. Second, having just read about the air bearings, I vote an air bearinged version to “keep the user’s hand cool and less sweaty.” :D

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