Tesla Coil Bullet-time Photography

June 29, 2011 by Mike Nathan 20 Comments

One thing we can all probably agree on is that Tesla coils are one part high-voltage electricity and two parts pure awesome. [Rob Flickenger] thinks so too, and he built a pretty nice one in his workshop some time ago. He took a bunch of pictures showing off the coil’s capabilities, but he thought that one photo taken from a single angle didn’t do much to relay just how fantastic it is to watch a Tesla coil in action.

Taking a cue from the Matrix movies, he bought a stack of Canon point and shoot cameras and constructed a bullet time rig in his workshop. In order to get the pictures just right, he flashed each camera with a customized version of the CHDK firmware that allowed him to trigger all ten shutters with a single button press. A few scripts help facilitate collecting all of the images for processing, after which he identifies the good shots and stitches them together. You can see the awesome results in the video below.

[via LaughingSquid]

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Ring Ring Ring Ring Ring Ring Ring Emotiphone!

June 25, 2011 by Mike Nathan 5 Comments

Instructables user [zvizvi] was working on putting together a portfolio for his application into Industrial Design school, and thought it would be neat to repurpose an old rotary phone that used to belong to his grandmother.

He originally had pretty lofty goals for the phone, but eventually pared back his vision to include one-way communications to Twitter. After gutting the phone of its unnecessary parts, he got busy installing LEDs behind the dialer’s finger holes. The LEDs were connected to an MCP23017 I/O expander, which takes its direction from an Arduino he crammed into the phone’s shell.

When the receiver is lifted from the cradle, the Arduino initiates a connection to the Internet via the WiFly shield he installed. Once he dials a number, the Arduino translates the digit into a predefined emoticon, posting it to his Twitter page. While the emoticons are not quite as descriptive as the messages from the Tweeting Roomba we featured earlier this week, they relay his mood just fine.

It’s a fun project, and it happened to get [zvizvi] into the design school he was applying at, so we can’t ask for much more than that.

“Zero Overhead” Z80 Computer Focuses On Performance

June 24, 2011 by Mike Nathan 33 Comments

z80_wirewrap_computer_zero_overhead

There’s something quite satisfying about building your own computer. Nowadays, constructing your own desktop PC is relatively easy, so if you really want to get your hands dirty, you have to take a step back in time and give some vintage hardware a spin.

[YT2095] has spent a good portion of the last two months building a computer based on the classic Z80 CPU. His machine, called “Z Eighty Development” or “ZED” for short is an amazing build, and most definitely a labor of love. He has put an estimated 700+ hours into this machine and it’s a beaut! When closed, the machine is pretty unassuming, but once he folds down the keypad, you can see that all of his time has been put to good use.

Most of the board’s components are connected together via wire wrap, including the large 48k memory card he built, as you can see from the link above. The wide array of add on cards all work together to accomplish his goal of “zero overhead” – freeing up the Z80 from having to do any unnecessary processing, such as I/O, etc.

It’s quite an impressive build, and ranks up there with some of the best Z80 based computers we have seen through the years.

Tiny Morse Code Trainer

June 23, 2011 by Brian Benchoff 18 Comments

[Eric] wanted to teach his kids Morse code, so he built a tiny Morse code trainer.

[Eric] built the trainer around an ATtiny85, and the rest of the circuit follows this minimalist idea. After connecting a piezo beeper and 6-pin ISP header, the only thing left to do was write a little code and start teaching his kids Morse. The Morse trainer is programmed to repeat the message, “SOS the moon rover has broken down and I am stuck in the trash can in the garden shed,” [Eric] planted a Lego moon rover in his shed as a prize for learning Morse, making him one of the coolest dads ever.

Although learning Morse isn’t required for an amateur radio license anymore, it’s a requirement for continuous wave radio. We think this is a great way to learn Morse the right way – actually hearing the characters – instead of memorizing the Huffman tree of Morse characters.

Modding A Car Charger To A Variable Power Supply

June 19, 2011 by Brian Benchoff 11 Comments

For an upcoming road trip, [Patrick] needed a small variable power supply. Instead of lugging around a bench supply, [Patrick] did the sensible thing and reverse engineered a cell phone charger to fit his requirements.

After cracking open an old Kyocera car charger, [Patrick] found a small PCB with completely labeled, all through-hole components – excellent reverse engineering potential. After finding an On Semi MC33063 IC, [Patrick] tore through the datasheets, generated a netlist, and developed a schematic that closely resembled the reference schematic given by the datasheets.

With all the grunt work done, [Patrick] set out to finish what he started – modifying the charger to output 3-10 Volts. After replacing a resistor with a 5k multiturn pot, [Patrick] was left with a power supply with a variable output from 2.8 to 8.8 Volts. Not exactly what was desired, but more than enough for the application at hand. While this hack isn’t a disco floor, it’s a great walkthough of the hacking process – building or modifying something to suit a need.

Homebrew TTL Logic Computer

June 17, 2011 by Brian Benchoff 48 Comments

Although [Jack] just graduated High School and doesn’t have much experience with electronics, that didn’t stop him from building the DUO Adept, a homebrew computer built entirely out of TTL logic chips.

The DUO Adept has 64k of memory, 6K of which is dedicated to the video ram that outputs a 240×208 black and white image onto a TV. Bootstrapping the computer to it’s current state was quite a challenge, as an entire OS was put into th system one bit at a time though DIP switches. After the OS was written to the computer, [Jack] was able to connect a keyboard and started programming. [Jack] programmed a hex editor and a few games of his own design. If all that wasn’t impressive enough, [Jack] also programmed an assembly compiler and emulator for his homebrew system.

We’ve seen a a few homebrew computersbefore, but not many of them are laid out on 17 breadboards like the DUO Adept. With skills like these, we can’t wait to see what [Jack] comes up with next. Check out the video after the break for a walk-through of the build.

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An Even Simpler Smartphone Garage Door Opener

June 15, 2011 by Nick Schulze 39 Comments

We have seen smartphone garage door openers in the past, but [Lou’s] Hack is beautiful in its simplicity. His door opener tackles the problem without using computers, Arduinos, wireless modules or even any smartphone based applications. For this project all that is needed is a Bluetooth headset and a single transistor. The door opener uses the Samsung HM1100 Bluetooth headset, which [Lou] has done significant testing on to show that his creation is quite secure and will not open the door unexpectedly.

When this headset connects to a phone it produces a beep from the earbud, so [Lou] removed the speaker and replaced it with a transistor. Now he can use the voltage spike produced by the amplifier before the beep as his switching signal. By wiring the transistor in parallel with the door button inside his garage he is able to open the door wirelessly by connecting then right away disconnecting from the headset. This setup is apparently perfectly secure as the only way to initially link your phone with the headset is to be inside the garage. Check out the video after the break for build instructions and a demonstration.

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