Fail Of The Week: Sand Casting Copper

June 7, 2017 by Dan Maloney 90 Comments

There’s trouble in the Kingdom of Random – the smithies of the realm are having trouble sand-casting copper. And while [King Grant] might not be directly asking for help, we think the Hackaday community might have plenty to say about his efforts.

We’ve all seen plenty of sand casting efforts before, including attempts to make otherwise unobtainable engine parts. And “lost foam” casting, where a model of the part is constructed of polystyrene foam that flashes off when the molten metal is poured, is a relatively new twist on the technique that’s been used to good effect on a recent Gingery lathe build. But most backyard foundries work in aluminum, which is apparently much easier to work with than the copper that [Grant Thompson] is working with. Ironically, his first pour worked the best — not perfect, but at least the islands defining the spokes of his decorative piece didn’t break off and float away as they did in every pour shown in the video below. That leads us to think that the greensand is too dry by the second video. Or perhaps the density of copper just makes it more likely for the sand to float. Maybe a cope and drag mold is in order to keep the islands in place and direct the flow of the copper better.

We know there’s a lot of expertise out there, so sound off in the comments about what you think is going on with these pours.

Continue reading “Fail Of The Week: Sand Casting Copper” →

Reading Bingo Balls With Microcontrollers

June 7, 2017 by Voja Antonic 38 Comments

Every once in a while a project comes along with that magical power to consume your time and attention for many months. When you finally complete it, you feel sorry that you don’t have to do anything more.

What is so special about this Bingo ball reader? It may seem like an ordinary OCR project at first glance; a camera captures the image and OCR software recognizes the number. Simple as that. And it works without problems, like every simple gadget should.

But then again, maybe it’s not that simple. Numbers are scattered all over the ball, so they have to be located first, and the best candidate for reading must be selected. Then, numbers are painted onto a sphere rather than a flat surface, sometimes making them deformed to the point where their shape has to be recovered first. Also, the angle of reading is not fixed but somewhere on a 360° scale. And then we have the glare problem to boot, as Bingo balls are so shiny that every light source reflects as a saturated bright spot.

So, is that all of it? Well, almost. The task is supposed to be performed by an embedded microcontroller, with limited speed and memory, yet the recognition process for one ball has to be fast — 500 ms at worst. But that’s just one part of the process. The project includes the pipelined mechanism which accepts the ball, transports it to be scanned by the OCR and then shot by the public broadcast camera before it gets dumped. And finally, if the reading was not reliable enough, the ball has to be subtly rotated so that the numbers would be repositioned for another reading attempt.

Despite these challenges I did manage to build this system. It’s fast and reliable, and I discovered some very interesting tricks along the way. Take a look at the quick demo video below to get a feel for the speed, and what the system “sees”. Then join me after the break to dive into the details of this interesting embedded build.

Continue reading “Reading Bingo Balls With Microcontrollers” →

Show Us Your Internet Of Useful Things By Monday

June 7, 2017 by Mike Szczys 14 Comments

Don’t forget to get your connected device entered in the Hackaday Prize by Monday morning. The current challenge is IuT ! IoT, a clever tilt at the Internet of Things, which is so hot right now. We don’t just want things to connect, we want that connection to be useful, so save your Internet Toasters and Twittering Toilets for another round.

So what are we looking for here? Any device that communicates with something else and thereby performs a service that has meaningful value. The Hackaday Prize is about building something that matters.

We’ve been covering a lot of great entries. HeartyPatch is an open source heart rate monitor and ECG that communicates through a smart phone. We’ve seen an affordable water level measuring station to help track when water levels are rising dangerously fast in flood prone areas. And the heads-up display for multimeters seeks to make work safer for those dealing with high voltages. Get inspired by all of the IuT ! IoT entries.

There’s $20,000 at stake in this challenge alone, as twenty IuT projects will be named finalists, awarded $1000 each, and move on to compete for the top prizes in the finals.

If you don’t have your project up on Hackaday.io yet, now’s the time. Once your project is published, entering is as easy as using the dropdown box on the left sidebar of your project page. [Shulie] even put together a quick video showing how to submit your entry. Check to make sure “Internet of Useful Things” is listed on your project’s sidebar and if not, use that dropdown to add it.

DIY Ram Pump Obeys The Laws Of Physics

June 7, 2017 by Dan Maloney 45 Comments

Despite the claims of “free energy” on the title of the video below, this is not yet another wacky perpetual motion story. We here at Hackaday fully support the laws of thermodynamics, and we think you should too. But you have to admit that a pump that works without any apparent energy inputs looks kind of shady at first glance.

The apparatus in question is a ram pump, a technology dating back all the way to the 18th century. The version that [Junkyard – Origin of Creativity] built uses commonly available materials like PVC pipes and fittings. About the only things on the BOM that might be hard to scratch up are the brass check valves, which should probably be flap valves rather than the easier to find spring valves. And the only custom part is an adapter to thread the plastic soda bottle that’s used as an air chamber to the PVC, which a 3D printer could take care of if you choose not to hack a bottle cap like [Junkyard] did. The video below shows the impressive lift achieved just by tapping the kinetic energy of the incoming flow.

There, the Second Law of Thermodynamics remains inviolate. But if you still think you can get something for nothing, check out our roundup of perpetual motion and Overunity quackery.

Continue reading “DIY Ram Pump Obeys The Laws Of Physics” →

Summer Is Approaching. Are You Prepared To Relax?

June 7, 2017 by James Hobson 5 Comments

[Blake Schreurs] found himself in dire straights — there was a critical lack of available hammocks in his immediate vicinity, and he wanted one. Fast. So he built a hammock stand in half an afternoon.

Initially dismayed by the cost of store-bought models, [Schreurs]’ hammock stand is perfect for woodworking-newbies and yard-loungers on a budget alike, as the build requires only a few straight cuts and some basic tools to whip up.

After cutting and laying out the lumber to make sure that it will all fit together as intended, [Schreurs] aligned and drilled holes through the pieces — don’t worry, he’s included the measurements in his post. Playing a game of connect-the-boards-with-carriage-bolts-nuts-and-washers — with a minor pause in the action to attach the feet to the base — all but finished this quick build. All that’s missing now is a hammock in which to recline!

One final note: be sure to use galvanized hardware for this — or any — project that’s expected to spend time out in the elements. Rust is not usually your friend!

Lounging in your backyard beginning to feel a little cramped? Take you relaxation on the road.