Power Protection Circuit Tutorial

January 4, 2012 by Brian Benchoff 17 Comments

Building your first circuit is empowering, but make sure it’s not too empowering. [Jon] sent in a great tutorial of power protection circuits to make sure you don’t release the mystical blue smoke that make electronics work.

There’s an in-depth tutorial of the classic series diode that’s the simplest of all power protection circuits. There’s not much to it – just a diode that provides reverse polarity protection. A fuse and parallel diode doesn’t have the voltage drop a series diode has, but doesn’t do anything for an overvoltage. A P-channel MOSFET gets around the problem of voltage drop, and [Jon] gives us some really nice empirical data to demonstrate his testing setup.

There’s a ton of nice write ups on [Jon]’s site that are perfect for getting ideas for projects like ten switches on one pin and some strange stuff [Jon] picked up at his Goodwill. If you’ve got any tutorials on general electronics, be sure to send them in on our tip line.

[Bob] Shows Us How To Make DIY Calendars For Vintage Computer Geeks

December 29, 2011 by Mike Nathan 1 Comment

[Bob Alexander] wrote in to share a hobby of his that we thought was pretty timely considering the new year is quickly approaching. For several years now he has put together a custom calendar for himself, including both dates he finds important along with sweet pictures of vintage computer equipment. Friends and family found his calendars so intriguing that they asked him to make some for them as well.

Each year his stack of calendar requests grew, and he found that no outlet – online or otherwise could produce exactly what he wanted. Instead of settling, he wrote a small application that lets him customize and print calendars to his heart’s content.

We think this is much cooler than buying one at your local bookstore, and we’re guessing that our readers likely agree. If you were creating your own custom calendar, what cool vintage computer hardware would you choose to display? What if you were designing a Hack-a-Day calendar? Let us know in the comments – we’re itching to find something interesting to look at while we count down to New Year’s Eve!

Ammo Tin ][

December 26, 2011 by Brian Benchoff 10 Comments

Ammo crate PCs have been around since Unreal Tournament LAN parties, but this one goes further back than that; [Simon] put an Apple II in an ammo crate. It’s a fitting anachronistic build from the same guy that built the TARDIS MAME cabinet.

Thankfully, [Simon] didn’t tear apart an Apple IIc for this build. A bare-bones Celeron motherboard was acquired for this project to run the AppleWin emulator. Instead of shoving all the parts into the box and calling it a day, [Simon] did it right and fabricated a very nice frame for the computer. With a wimpy CPU and no expansion cards, the Ammo Tin ][ can run very cool without drawing a lot of power.

We really have to hand it to [Simon] for this build. The metal work on this build looks great (it should for someone who is rebuilding an Austin 7), and we’ve got to respect the love for the Apple II. Now all that’s needed is a real Apple II keyboard on that USB port.

We’re On An Atari Jaguar Kick, Apparently

December 24, 2011 by Brian Benchoff 11 Comments

We don’t know why, but the Atari Jaguar is getting a lot of attention this week. [10P6] just came up with this Jaguar/CD combo that reminds us what Atari could have come up with in 1993.

The build itself is relatively simple once you get past [kevincal]’s ‘April Fools’ type joke he played on the Atari Age forum. [10P6] took a regular Jaguar CD drive and cut a hole into a Jaguar case. The whole case mod took less than a three hours, but [10P6] gives us a lot of commentary into what Atari could and/or should have built in 1993.

[10P6] suggests this type of Jaguar would have saved Atari money if the CD drive was stock on the base unit and released at a slightly increased price. This would cut out the cost of the cart slots and reduced the amount of plastic in manufacturing. [10P6] also talks about how Atari engineers could have dropped the 68000 coprocessor with an increase in the system clock. We’re not quite fond of that idea (ask us about our tattoo), but the logic does make sense.

Of course, this build comes on the heels of the Jaguar Portable we saw a few days ago. Honestly, we have no idea what’s going on with the Jaguar build.

Numitron Tube Tutorial

December 21, 2011 by Brian Benchoff 24 Comments

Nixies and VFDs are great displays, but when using them you’ve got to deal with some fairly high voltages, at least for the micro projects we see on Hack a Day. Luckily, there’s another ancient technology that can be driven at tiny voltages. [Kenneth] put up a great tutorial on Numitron tubes to show the Internet how to get these guys working.

Numitron tubes are like Nixies, but instead of the ten number-shaped filaments in each Nixie, Numitrons are old-school seven-segment displays. [Kenneth] picked up a few on ebay and the seller was kind enough to include a Russian data sheet. Each filament in his IV-9 Numitrons required about 20mA to light up, perfect for the constant current LED drivers [Kenneth] picked up

The test circuit consisted of an ATtiny2313 and an A6278 LED driver. The code on the ATtiny cycles the digits 0 through 9. This is sent through the LED driver and lights up the tiny filaments inside the tube. Check out the video after the break to see the Numitron in action

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Rebuilding Dried Out Capacitors

December 9, 2011 by Brian Benchoff 31 Comments

If you’ve ever torn into very old equipment for a little refurbishment, you’ve seen ancient capacitors among tube sockets and carbon resistors. These caps are long past their life expectancy and are dried out. Putting a brand-new metal can cap in a piece of equipment from the 40s just seems wrong, though. Luckily, [unixslave] posted a nice cap rebuilding tutorial on the Hack a Day forum.

To get inside, [unixslave] melted the resin and wax plug at the base of an old cap with a soldering iron. After cleaning out 70-year-old goo with the tip of a flathead screwdriver, he drilled a hole through the core of the cap.

[unixslave] took the old wax-pressed tube of the old cap and put some modern electrolytics inside. The result reminds us of a shady practice happening in a cap factory somewhere, but [unixslave] is keeping everything on the level. The repaired cap has the same value as what’s on the label, just enough to get that old tube amp working.

Hack A Webcam And A Film Camera Into A USB Microscope

December 8, 2011 by Caleb Kraft 8 Comments

Most of you probably have a webcam sitting around somewhere, and after all the high voltage projects you’ve done using disposable cameras, we bet you have some camera lenses too. You could always do what [Butch] did and combine the lens from the camera with the webcam to do some up close inspection.

This seems like something we’ve seen several times, but we can’t find it in our archive. Such a simple and quick hack looks surprisingly effective in his shots. If you want to see the details, like where he tied into the webcam’s board to power an external LED, you’ll have to download the PDF.