Ping Pong Ball-Juggling Robot

January 22, 2017 by 6 Comments

There aren’t too many sports named for the sound that is produced during the game. Even though it’s properly referred to as “table tennis” by serious practitioners, ping pong is probably the most obvious. To that end, [Nekojiru] built a ping pong ball juggling robot that used those very acoustics to pinpoint the location of the ball in relation to the robot. Not satisfied with his efforts there, he moved onto a visual solution and built a new juggling rig that uses computer vision instead of sound to keep a ping pong ball aloft.

The main controller is a Raspberry Pi 2 with a Pi camera module attached. After some mishaps with the planned IR vision system, [Nekojiru] decided to use green light to illuminate the ball. He notes that OpenCV probably wouldn’t have worked for him because it’s not fast enough for the 90 fps that’s required to bounce the ping pong ball. After looking at the incoming data from this system, an algorithm extracts 3D information about the ball and directs the paddle to strike the ball in a particular way.

If you’ve ever wanted to get into real-time object tracking, this is a great project to look over. The control system is well polished and the robot itself looks almost professionally made. Maybe it’s possible to build something similar to test [Nekojiru]’s hypothesis that OpenCV isn’t fast enough for this. If you want to get started in that realm of object tracking, there are some great projects that make use of that piece of software as well.

Newton’s Cradle For Those Too Lazy To Procrastinate

January 22, 2017 by 11 Comments

Desk toys are perfect for when you don’t want to work. There’s a particularly old desk toy called the Newton’s cradle. If you don’t know the name, you’d still recognize the toy. It is some ball bearings suspended in midair on strings. If you pull back, say, two balls and let them swing to impact the other balls, the same number of balls on the other side will fly out. When they return, the same number will move on the other side and this repeats until friction wears it all down.

We think [JimRD] might be carried away on procrastination. You see, he not only has a Newton’s cradle, he has automated it with an Arduino. According to [Jim], this is his third attempt at doing so. You can see the current incarnation in the video, below.

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An Eight Inch Floppy For Your Retrocomputer

January 22, 2017 by 38 Comments

For people under a certain age, the 8 inch floppy disk is a historical curiosity. They might just have owned a PC that had a 5.25 inch disk drive, but the image conjured by the phrase “floppy disk” will be the hard blue plastic of the once ubiquitous 3.5 inch disk. Even today, years after floppies shuffled off this mortal coil, we still see the 3.5 inch disk as the save icon in so many of our software packages.

For retro computing enthusiasts though, there is an attraction to the original floppy  from the 1970s. Mass storage for microcomputers can hardly come in a more retro format. [Scott M. Baker] evidently thinks so, for he has bought a pair of Qume 8 inch floppy drives, and interfaced them to his CPM-running RC2014 Z80-based retrocomputer.

He goes into detail on the process of selecting a drive as there are several variants of the format, and interfacing the 50 pin Shuggart connector on these drives with the more recent 34 pin connector. To aid in this last endeavour he’s created an interface PCB which he promises to share on OSH Park.

The article provides an interesting insight into the control signals used by floppy drives, as well as the unexpected power requirements of an 8 inch drive. They need mains AC, 24VDC, and 5VDC, so for the last two he had to produce his own power supply.

He’s presented the system in a video which we’ve put below the break. Very much worth watching if you’ve never seen one of these monsters before, it finishes with a two-drive RC2014 copying files between drives.

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The Impressive Z80 Computer With The Unfortunate Name

January 22, 2017 by 40 Comments

We’ve seen a lot of retro builds around the Z80. Not many are as neatly done or as well-documented as [dekeNukem’s] FAP80 project. Before you rush to the comments to make the obvious joke, we’ll tell you that everyone has already made up their own variation of the same joke. We’ll also tell you the name is a cross between an old design from [Steve Ciarcia] called the ZAP80 and a reference to the FPGA used in this device.

[dekeNukem] says his goal was to create a Z80 computer without all the baggage of using period-correct support chips. You can argue about the relative merits of that approach versus a more purist build, but the FAP80 has a 5 slot backplane, VGA output, a PS/2 keyboard port and more. You can see one of many videos showing the machine below.

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Stuff An Android In Your Xbox Controller’s Memory Slot

January 22, 2017 by 5 Comments

What is this, 2009? Let’s face facts though – smartphones are computing powerhouses now, but gaming on them is still generally awful. It doesn’t matter if you’ve got the horsepower to emulate any system from the last millennium when your control scheme involves awkwardly pawing away at glass when what you need is real buttons. You need a real controller, and [silver] has the answer – a 3D printed phone mount for the original Xbox Controller.

It’s more useful than it initially sounds. The original Xbox used USB 1.1 for its controllers. With a simple OTG cable, the controllers can be used with a modern smartphone for gaming. The simple 3D printed clamp means you can have a mobile gaming setup for pennies – old controllers are going cheap and it’s only a couple of dollars worth of filament. The trick is using the controller’s hilariously oversized memory card slots – for some reason, Microsoft thought it’d be fun to repackage a 64MB flash drive into the biggest possible form factor they could get away with. The slots also acted as a port for online chat headsets, and finally in 2017, we’ve got another use for the form factor.

For the real die-hard purists, [silver] also shares a photo of a similar setup with a Nintendo 64 controller – including a big fat USB controller adapter for it, hanging off the back. Not quite as tidy, that one.

It’s a neat little project – we love to see useful stuff built with 3D printers. If you’ve been looking for something functional to print, this is it. Or perhaps you’d like to try these servo-automated 3D printed light switches?

Vive Tracker Brings Easier VR Hacking

January 22, 2017 by 10 Comments

CES 2017 is over and there were VR gadgets and announcements aplenty, but here’s an item that’s worth an extra mention because it reflects a positive direction we can’t wait to see more of. HTC announced the Vive Tracker, to be released within the next few months.

The Tracker looks a bit like a cross between a hockey puck and a crown. It is a self-contained, VR trackable device with a hardware port and built-in power supply. It can be used on its own or attached to any physical object to make that object trackable and interactive in VR. No need to roll your own hardware to interface with the Vive’s Lighthouse tracking system.

Valve have been remarkably open about the technical aspects of their hardware and tracking system, and have stated they want to help people develop their own projects using the system. We’ve seen very frank and open communication on the finer points of what it took to make the Lighthouse system work. Efforts at reverse-engineering the protocol used by the controller even got friendly advice. For all the companies making headway into VR, Valve continues to be an interesting one from a hacking perspective.

[Image source for bottom of Tracker: RoadToVR]

 

Heavy Metal Chess

January 21, 2017 by 31 Comments

Chess is a slow game of careful decision-making, looking several moves ahead of the current state of the board. So is machining, and combining the two is an excellent way to level up your machine shop chops. And so we have the current project from [John Creasey] who is machining a chess set out of stainless steel.

This isn’t that new-fangled computer numerical control at work, it’s the time-tested art of manual machining. Like chess, you need to plan several steps ahead to ensure you have a way to mount the part for each progressive machining process. In this first video of the series [John] is milling the knights — four of them, with two which will eventually get a black oxide treatment.

Milling the horse head is fun to watch, but you’ll be delighted when the work gets to the base. [John] is using a pipe fitting as a fixture to hold the already-milled horse-head-end while working the base on his lathe. The process begins by getting rid of the inner threads, then working the pipe fitting very carefully to the diameter of the chess piece for a perfect press fit. Neat!

At the end, [John] mentions it took “quite a few months of weekends to get to this point” of having four pieces made. They look great and we can’t wait to see the next piece in the set come to life. You’ll find the video embedded below, but if you can’t sink this kind of time into your own chess set, you may try three-dimensional laser cut acrylic pieces.

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