Circuit Building With A Hammer And Nails


[Collin Cunningham] over at Make recently wrapped up another edition of “Collin’s Lab” – this time around, the subject is breadboards. He starts off by discussing a common solderless breadboard, something you are no doubt familiar with. What you might not know however is how breadboards got their name.

Way back when, before there was a RadioShack in every strip mall across the country, fancy prototyping supplies like your solderless breadboard did not exist. Amateur radio operators would prototype circuits on wooden boards, often using whatever was around as a substrate. Many times, this meant that the family’s cutting board ended up as a makeshift prototyping station.

One popular method of building circuits was to drive small nails into the breadboard, using wire wrapping to connect things together. [Collin] demonstrates this technique in the video, constructing a simple LED flasher circuit.

He says that the process works decently enough, and was kind of fun to do. He does mention however that building any sort of circuit requiring an IC would likely be out of the question.

If you have a few minutes to spare, check out the video embedded below – [Collin’s] take on technology is quirky and entertaining as always.

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Building An Augmented Reality Display Using Obsolete Technology


Augmented reality might be all the rage these days, but when you take a closer look at the technology, you will find that these sorts of optical illusions are not new at all.

Artist [Sebastian Schmieg] was pondering augmented reality for a bit and decided he could replicate the effect using old and obsolete technology. His creation, called “81 Points of View”, uses an old Kodak slide projector and an elaborate mechanical setup to simulate the effect.

The slide projector resides on a platform that can be rotated around its center in 81 steps. After each movement, the mechanism swaps out the current slide, selecting the next image depending on which direction the user turns. The resulting effect is similar to the implementations of augmented reality you might see today, with a 3d visualization superimposed on the surrounding room.

The concept dates back all the way to the 1860’s, when [John Pepper] first demonstrated the technique. Using mirrors and panes of glass, he was able to project translucent images in front of his audience, which is the same idea [Sebastian] uses in his project. You are likely quite familiar with the effect, if you have ever visited the Haunted Mansion at a Disney theme park.

It’s a neat project, though the resultant augmented reality display is obviously not quite as smooth as you would see from a smartphone. Either way, it is definitely worth checking out. Keep reading to see a video of the project in action.

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15-digit Nixie Clock Contains Mostly Non-useful Information

[Jarek Lupinski] is at it again, this time building a clock using 15 Nixie tubes. Just look at the time…. wait, how do you read this now? It’s not seconds since the epoch, but an homage to a very expensive New York City art piece. [Jarek] took his inspiration from the Metronome art installation in Union Square.

We hadn’t heard of it before and were shocked to learn that this art was commissioned at $4.2 million. It belches steam and confuses passersby with its cryptic fifteen digits. It seems that the eight digits on the left mark the current time – two digits for hours, two for minutes, two for seconds, and the final digit for hundreths of a second. The seven remaining digits count down the time left in the day. So when you watch it, you see the significant digits of the display increasing, and the insignificant half decreasing.

The Nixie version rests snuggly on a 15″x4″ PCB. We’re sure it doesn’t number in the millions, but that couldn’t have been cheap to have manufactured. Each tube has its own driver chip, removing the need for multiplexing. An ATmega168 controls the clock (along with some shift registers to expand the I/O count), reading time from a DS1307 RTC chip. It looks fancy, but where’s the belching smoke on this version?

Baking Pan Tube Amp Sounds Better Than You’d Expect


A few years back, [Gio] decided to try his hand at building a couple of tube amplifiers.

The first amp was more of an experiment to see how well a DIY single-ended tube amp would sound. The amp is based off the 6T9 design created by Spare Time Gizmos, and incorporates a pair of 6T9 vacuum tubes, hence the name.  He wired things up in an afternoon, then got busy drilling holes in a baking pan, where he mounted the amp. Bear with us for a second, it’s not as bad as it sounds. The amp actually looks pretty good mounted in the dark black steel, and this sort of enclosure is far cheaper than most DIY amp enclosures. He says that he was sure to be extra careful in isolating all of the electronic components from the metal chassis.

The second amp was built to test the performance differences between Pentode-mode and Ultra-Linear mode configurations. While both amps share a substantial amount of the same components, his UL amp benefits from slightly better capacitors and an uprated power supply, not to mention a more conventional case.

Both amps sound great, according to [Gio], but should be paired with efficient speakers for the best experience. He does note that the ultra-linear amp is the better choice, mounting options aside.

[Thanks, Philippe]

[via RetroThing]

AVR HVSP On A Tiny Breadboard

AVR chips are convenient because you can program them in circuit at their operating voltage. That is, unless you screw up the fuse settings and they’ll no longer listen to an In System Programmer. If you find yourself facing this problem, just build this circuit on a breadboard and ‘unbrick’ by holding down the button.

The circuit seen above is a High Voltage Serial Programmer. This is one of two high voltage protocols used by AVR chips; HVSP is for chips that don’t have enough pins to use High Voltage Parallel Programming. This rendition uses a 12V power source, which is the level necessary for the high voltage method. A 7805 linear regulator joins the mix to provide operational voltage, along with one transistor, an ATtiny2313 to control the circuit, a four-digit 7-segment display for feedback, and one button for control.

Watch the video after the break to see an ATtiny13 programmed to disable the reset pin using a breadboarded programmer. That chip is then easily rescued, having been automatically recognized by using its device signature.

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Alternate Keyboard Layouts – For Geekiness And Other Reasons

[BiOzZ] wanted to try a different keyboard layout than the ubiquitous Qwerty, so he grabbed an old keyboard and converted it to the Dvorak setup. This was accomplished by first popping off all of the keys from the black keyboard seen above, and boy did he find a mess underneath. It was nothing that a trip through the dishwasher (for the case only) wouldn’t fix, and the next step was to replace the keys in a different order. He found that a couple of them wouldn’t just go back in a different place, but had to be rotated 90 degrees to fit. Not a huge problem, you can see that he overcame the visual speedbump of letters facing the wrong way by adding his own letter labels. From there he walks us through the process of getting Windows to switch to the Dvorak layout.

I went through a similar process at the end of last year. I was experiencing a lot of pain in my hands from my prolific feature writing here at Hackaday so I chose to try out the Colemak keyboard. The white keyboard above is the one I repurposed using that layout. I found it quite easy to switch between two keyboard layouts using Ubuntu. After you’ve set it up in the keyboards dialog a layout icon appears on the panel. It wasn’t hard to pick the new key locations up, but it did reduce my typing speed by a factor of 8. In the end I found that adjusting my chair height and keeping my hands warm did the trick and I’m back on the Qwerty where I belong.

Blu-ray Laser Plotter Writes On Glow-in-the-dark Screen

This laser display is persistent thanks to a glow-in-the-dark screen. [Daniel] built it using a Blu-ray laser diode. As the laser dot traverses the screen, it charges the phosphors in the glow material, which stay charged long enough to show a full image.

The laser head is simple enough, two servo motors allow for X and Y axis control. A Micro Maestro 6-channel USB servo controller from Pololu drives the motors, and switches the diode on and off. This board offers .NET control, which [Daniel] uses to feed the graphics data to the unit. Check out the video demonstration below the fold to see a few different images being plotted. It’s shot using a night-vision camera so that you can really see where the laser dot is on the display. It takes time to charge the glow material so speeding up the plotting process could actually reduce the persistent image quality.

This is yet another project that makes you use those geometry and trigonometry skills.

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