Homemade Omnidirectional Speakers in a Unique Enclosure

While studying acoustics in college (university for non-Americans), [Nick] had a great idea for an omnidirectional speaker. Some models available for purchase have a single speaker with a channel to route the sound in all directions, but [Nick] decided that a dodecahedron enclosure with 12 speakers would be a much more impressive route.

To accommodate the array of speakers, the enclosure needs twelve pentagons with a 58.3 degree bevel so that they fit together in a ball shape. After thinking about all of the complicated ways he could get this angle cut into the wood pentagons, he ended up using a simple circular saw!

Once the enclosure was painted [Nick] started wiring up the speakers. The equivalent impedance of the array of 8-ohm speakers works out to just around 10 ohms, which is easily driven by most amplifiers. The whole thing was hung from a custom-made galvanized pipe (all the weight adds up to about 15 kilograms, or 33 pounds for Americans, so the rig needed to be sturdy). We’ve featured other unique speaker builds, but this is the first 12-speaker omnidirectional speaker we’ve seen. [Nick] is happy to report that the speakers sound great, too!

Welcome to the Garage of the Future

Over the last several years, hackerspaces have cropped up all over the world. These places have become a home base for hackers, tinkerers, makers, designers, and engineers alike. One of the biggest problems associated with these creative environments is the hours that are typically available. A lot of the time you just can’t walk in at odd hours of the night and expect to do anything at all. Granted, the best hackerspaces give out 24 hour access keys to those that pay for it, but sometimes it just feels better to do the work from the comfort of one’s home. Also, if a person doesn’t have the privilege of having a hackerspace in the area, then transforming a garage into a work shop can provide a nice entry point into the continuation of the maker revolution.

A trend is emerging where garages are being turned into hackerspace-like workshops that are neatly packed away within ordinary neighborhoods. A great example is EdsJunk Home Shop. His two car garage was converted into a maker shop complete with 3D printers, laser cutters, CNC machines, and more tools than one can dream of. The key, as [Ed] states, to creating such a useful home shop is organizing everything strategically.

This project has been a 5 year venture so far and there is still plenty to do. Years of experience have taught [Ed] to coordinate the tools in out-of-the-box ways. His air compressor, for instance, is stored in the attic with a retractable hose descending from the roof down into the garage which helps to save space and reduce noise.

Continue reading “Welcome to the Garage of the Future”

Update: 3D Printed Concrete Castle Completed

After two years of dreaming, designing, and doing, [Andrey Rudenko] has finally finished 3D printing his concrete castle. We’re sure a few readers will race to the comments to criticize the use of “castle” as an acceptable descriptor, but they’d be missing the point. It’s been only three months since he was testing the thing out in his garage, and now there’s a beautiful, freestanding structure in his yard, custom-printed.

There are no action shots of the printer setup as it lays down fat beads of concrete, only close-ups of the nozzle, but the castle was printed on-site outdoors. It wasn’t, however, printed in one piece. [Andrey] churned out the turrets separately and attached them later. He won’t be doing that again, though, because moving them in place was quite the burden. On his webpage, [Andrey] shares some insight in a wrap-up of the construction process. After much experimentation, he settled on a layer height of 10mm with a 30mm width for best results. He also discovered that he could print much more than his original estimation of 50cm of vertical height a day (fearing the lower layers would buckle).

With the castle a success, [Andrey] plans to expand his website to include a “posting wall for new ideas and findings.” We’re not sure whether that statement suggests that he would provide open-source access to everything or just feature updates of his future projects.

Wooden supports for concrete bridging.
[Andrey] used wooden supports to print concrete bridges.
We hope the former. You can check out its current format as the Architecture Forum, where he explains some of the construction capabilities and tricks used to build the castle.

His next project, a full-scale livable structure, will attempt to print 24/7 (weather permitting) rather than the stop-start routine used for the castle, which turned out to be the culprit behind imperfections in the print. He’ll have to hurry, though. [Andrey] lives in Minnesota, and the climate will soon cause construction to take a 6-month hiatus until warm weather returns. Be sure to check out his website for more photos and a retrospective on the castle project, as well as contact information—[Andrey] is reaching out to interested parties with the appropriate skills (and investors) who may want to help with the new project.

[via 3ders.org]

[Thanks Brian]

Hydropower from a Washing Mashine

Living off the grid is an appealing goal for many in the hacker community, perhaps because it can fulfill the need to create, to establish independence, to prepare for the apocalypse, or some combination of all those things. [Buddhanz1] has been living off the grid for awhile now by harnessing power from a nearby stream with an old washing-machine-turned-generator.

He started with a Fisher & Paykel smart drive, which he stripped down to the middle housing, retaining the plastic tub, the stator, the rotor, the shaft, and the bearings. After a quick spot check to ensure the relative quality of the stator and the rotor, [Buddhanz1] removed the stator and rewired it. Unchanged, the stator would output 0-400V unloaded at 3-4 amps max, which isn’t a particularly useful range for charging batteries. By rewiring the stator (demonstration video here) he lowered the voltage while increasing the current.

The key to this build is the inclusion of a pelton wheel—which we’ve seen before in a similar build. [Buddhanz1] channeled the water flow directly into the pelton wheel to spin the shaft inside the tub. After adding some silicon sealant and an access/repair hatch, [Buddhanz1] painted the outside to protect the assembly from the sun, and fitted a DC rectifier that converts the electricity for the batteries. With the water pressure at about 45psi, the generator is capable of ~29V/21A: just over 600W. With a larger water jet, the rig can reach 900W. Stick around for the video after the break.

Continue reading “Hydropower from a Washing Mashine”

Adding Features to the DoorBot

network sniffing doorbell

There’s an interesting network-enabled doorbell on the market from Edison Junior called the DoorBot that boasts some useful features, notably that it can make calls to a phone when someone pushes the button for the doorbell. However, [MadBeggar] saw the potential in this device and couldn’t wait to get some more functionality out of it, so he has reverse engineered the communications protocol for the doorbell.

His goals for the project were to implement third-party notifications such as text messaging, VoIP/SIP integration, and maybe even a desktop client. So far he has only been able to analyze the communications protocol but he hopes that others will be able to build upon his work or even add features he hasn’t thought of yet. The makers of the device promise to eventually deliver on some of these features but so far haven’t delivered.

There are some other projects out there that integrate wireless connectivity with a doorbell. However, [MadBeggar] notes that the DoorBot really stands out among all of the internet-enabled doorbell, mostly because nothing else around is as clean or is as easy to install as the DoorBot. He just wishes that the software wasn’t so clunky and that it had its full potential unlocked with these extra features. We’d say he’s on the right track!

ATtiny Watering Timer Turns off the Water When You Forget

ATtiny Water Timer

A pal of [Kyle's] was regularly leaving his sprinkler on for too long. He also had forgotten to turn the water off while topping off his pool a couple of times, an embarrassing and wasteful situation. Being such a good friend, [Kyle] offered to make him a water timer. This isn’t a regular water timer that turns the water on and off at the same time every day. This device allows the user to push a button to have the unit switch on a solenoid valve, permitting water flow. After a predetermined amount of time the unit removes power to the solenoid valve which stops the water flow, successfully preventing pool overflows and excessive watering.

[Kyle] started off his design using a 555 chip to do the counting. He quickly became worried that timer lengths over 10 minutes would cause inconsistent functionality due to the leakage current of the capacitor and the charge current of the resistor. There are ways around this, but rather than complicate the design he switched to an ATtiny microcontroller. The added benefit of the ATtiny is that he could connect up a potentiometer to adjust the on-time without replacing parts or making a new unit. When the potentiometer is turned, the on-board LED will flash a number of times which corresponds with the delay in minutes. Ten flashes means a 10 minute delay. It’s a simple and clear interface.

As if the home etched PCB wasn’t cool enough, [Kyle] 3D printed up a case for the unit. The case permits access to the screw terminals and has provisions for the indicator LEDs. Check out the integrated flap in the top of the case. When this portion of the case is pushed in, it presses the PCB-mounted on/off switch.

If you are interested in making one, all of the files and code are available on [Kyle's] site.

via [dangerous prototypes]

Arduino Gives Your Toilet Options

toilet water saver

With the severe drought going on in California with no end in sight, [TVMiller] decided he could put an Arduino and a toilet together to try and save at least a few gallons of water per day. The invention fills a toilet to the minimum level, saving around two gallons per day for the average “user”.

A typical toilet functions by using gravity and moving water to create a vacuum, sucking the waste down and out of the toilet. As long as there is nothing, uh, solid in the bowl, the toilet will be able to function on the reduced amount of water. The Arduino cuts the flow of water off before the toilet fills up the entire way.

In the event that anyone -ahem- needs the toilet’s full capacity, there is a button connected to the Arduino that fills the reservoir to capacity. [TVMiller] notes that if 1,825 hackers installed this device on their toilets, we could save a million gallons of water per year and be well on our way to saving the planet.

The project site is full of more information and puns for your viewing pleasure. We might suggest that the “2″ button would be very easy to integrate with the toilet terror level indicator as well.