Mechanical Skeeball Built From Knex

August 15, 2012 by 18 Comments

We don’t really know what to say. This Skeeball cabinet is built entirely from Knex. It works exactly how you’d expect Skeeball to work. You plug in quarter and it dispenses balls and keeps score.

[Shadowman39] worked on the build for more than a year. Everything that went into it is a Knex part with the exception of a few rubber bands, and the paper numbers that are used on the scoreboard. There are six motors which drive the machine. Four of them are responsible for turning the scoreboard digits, the others handle ball return.

The link at the top starts off with a bunch of images of the various parts, but you’ll want to watch the video after the break for a closer look. It shows the coin hopper in greater detail. It’s built to only accept quarters and to reject all other coins.

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Connect 4 Binary Clock

August 15, 2012 by 5 Comments

As part of a class at University, [Emacheen22] and his teammates turned an old Connect 4 game into a binary clock. This image shows the device nearing completion, but the final build includes the game tokens which diffuse the LED light. We enjoy the concept, but think there are a few ways to improve on it for the next iteration. If you’re interested in making your own we’d bet you can find Connect 4 at the thrift store.

Instead of using the free-standing game frame the team decided to use the box to host the LEDs and hide away the electronics. Since they’re using a breadboard and an Arduino this is a pretty good option. But it means that the game frame needs to be on its side as the tokens won’t stay in place without the plastic base attached. They used a panel mount bracket for each LED and chose super glue to hold all of the parts together.

We think this would be a lot of fun if the frame was upright. The LEDs could be free-floating by hot glueing the leads to either side of the opening. Using a small box under the base, all of the electronics can be hidden from view. After all, if you solder directly and use just a bare AVR chip there won’t be all that much to hide. Or you could get fancy and go with logic chips instead of a uC.

Automatic Speaker Control Via TV

August 15, 2012 by 5 Comments

[Jon] wanted his speakers to come on and off along with his TV. The speaker heats up if left on so he didn’t want to do that. But killing the power also resets the volume level (this is an old set of PC speakers and the remote is wired, not IR) so using one of those switched power strips was out as well. He thought a bit about trying to use the power LED on the TV to build his own circuit when it dawned on him. It’s possible to monitor the USB port on the TV and use it to switch on the speakers.

The circuit above uses a couple of opto-isolators to protect both the television and the speakers. The 5V line from the USB port on the back of the TV is monitored by an XNOR gate (which helps to filter out some of the toggling at power-on). When that gate latches it activates a 555 timer which in turn fires up the speakers. Presumable this happens when power is cut as well, but we’ll let you work through the circuit logic yourself.

Buying Cheaper Electronics And Not Saving Money

August 15, 2012 by 125 Comments

As an engineer at Spectrum Design in Minneapolis, [Carl] works with clients to get their product out to the masses. When designing a new USB-powered device, one client thought it would be a great idea to include a USB car charger with the device. The client promptly ordered a few thousand car chargers from China and everything was going swimmingly.

Everything was fine, of course, until [Carl] decided to test the Chinese car chargers with the client’s device. The USB PHY burnt out in short order, and the likely culprit was a shorted 12 volt regulator. This demanded a closer inspection, so after cracking open the charger [Carl] was amazed at what he found.

Yes, what you see on that circuit board is accurate. The manufacturer of these car chargers never even populated the switched mode regulator for this car USB charger.  Amazing, considering a single 10 cent 7805 DC regulator would have almost worked for this application.

If there was ever an example of being careful when purchasing the cheapest possible product to increase profit margins, this would be it.

Ever the engineer, [Carl] sent this into the tip line as a Word document. That’s available here, along with a slide show of the pictures [Carl] snapped.

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Toorcamp: Bliplace 2.0

August 15, 2012 by 7 Comments

We’ve shown [Tanjent]’s Bliplace 1.0 in the past. He handed out a few hundred of the open source audio toys at Burning Man. At Toorcamp, he’s been showing off an improved 2.0 version of the project. This one has a more powerful microcontroller and many more RGB LEDs.

The device uses the ATMega328 and an electret microphone to sample ambient noise. It the processes the sound into a light pattern which is displayed on the line of RGB LEDs. The demo that I saw showed the LEDs synchronized to bass frequencies, which it could pick up at a range from the large sub-woofers at Toorcamp. It’s powered by a CR2032 coin cell battery, which means it can be worn as a neat audio toy.

This prototype version was etched in his kitchen but [Tanjent] is working on making a production version of the PCB. He plans to release it as a surface mount soldering kit.

Hackaday Links: August 15, 2012

August 15, 2012 by 9 Comments

An Octopart for RC equipment

When [Zach] started building a quadcopter he found it very difficult to source the required parts. Thus was born CompareRC, an aggregation of several online RC retailers. There’s over 150,000 parts in the database, all searchable and sortable by lowest price.

Segway iPad Skype teleconferencing robot

It’ll be a while until robots completely eliminate the need for any human interaction, but until then there’s Double. It’s a two-wheeled balancing robot with an iPad dock, controllable via a remote iPad.

Free electronic design

In case you weren’t aware, Fedora has an electronic design distro that includes just about everything needed to build electronic circuits called Fedora Electronic Lab. FEL has PCB designers, circuit simulators, editors for just about everything, and support for PICs, AVRs, and 8051 micros. Thanks for sending this in, [Simon].

Make your own Megadrive ROMs

Last month, [Lee] sent in a build where he connected an Arduino Mega to an old Sega Genesis/Megadrive cartridge. He’s figured out how to read the contents of the cartridge now, allowing you to preserve your 100% complete Sonic & Knuckles / Sonic 3 save for time immemorial.

A surprising amount of graphics tutorials

Khan Academy, every autodidacts best friend, is now teaching computer science. Right now, there is a heavy focus on drawing graphics, and everything is coded in the browser (using Javascript…), but at least it’s a start. The fundamentals of programming are platform and language agnostic, so this looks to be a great way to learn programming.

Here’s a blog post from the lead dev of the Khan CS project.