FaBrickation: Combining Lego And 3D Printing

January 28, 2014 by Eric Evenchick 29 Comments

While 3D printing gives you the ability to fabricate completely custom parts, it does have some drawbacks. One issue is the time and cost of printing large volumes. Often these structures are simple, and do not require completely custom design.

This is where the faBrickation system comes in. It allows you to combine 3D printed parts with off the shelf LEGO bricks. The CAD tool that lets you ‘Legofy’ a design. It creates directions on how to assemble the LEGO parts, and exports STL files for the parts to be 3D printed. These custom bricks snap into the LEGO structure.

In their demo, a head mounted display is built in 67 minutes. The same design would have taken over 14 hours to 3D print. As the design is changed, LEGO blocks are added and removed seamlessly.

Unfortunately, the tool doesn’t appear to be open source. It will appear for the ACM CHI Conference on Human Factors in Computing Systems, so hopefully we will see more in the future. Until then, you can watch the demo after the break.

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A Deep Dive Into NES Tetris

January 28, 2014 by Eric Evenchick 17 Comments

Back in 1989, Nintendo released Tetris for the NES. This detailed article first explains the mechanics of how Tetris works, then builds an AI to play the game.

To understand the mechanics of the game, the ROM source was explored. Since the NES was based of the MOS 6502 microprocessor, this involves looking at the 6502 assembly. The article details how the blocks (called Tetriminos) are created and how they move across the screen. The linear feedback shift register used for random number generation is examined. Even details of the legal screen and demo mode are explained.

After the tour through how Tetris works, an algorithm for the AI is presented. This AI is implemented in Lua inside of the FCEUX NES/Famicom emulator. It works by evaluating all of the possible places to put each new Tetrimino, and choosing the best based on a number of criteria. The weighting for each criterion was determined by using a particle swarm optimization.

The source for both the Lua version and a Java version of the code is available with the article. Everything you need to run the AI is available for free, except the Tetris ROM. If you’re interested in how 8 bit games were built, this dissection is a great read.

[via Reddit]

A Video Vectorscope Oscilloclock

January 26, 2014 by Eric Evenchick 14 Comments

Back in the days of analog TV, vectorscopes were used to view video signals. [Aaron] has taken an old Tek 520A NTSC vectorscope and converted it into his newest oscilloclock.

The scope was originally designed to look at the signal provided by composite video. It draws vectors on a polar plot. By using test patterns such as color bars, you can ensure equipment is creating the correct color output. These scopes were so commonly used that many digital systems still provide a simulated vectorscope for color analysis. Vectorscopes were designed to be left on constantly, which is a good quality for a clock.

[Aaron] has a history of converting oscilloscopes into clocks, which we have featured in the past. This build is similar, using his custom control hardware to drive the display. Since analog vectorscopes are pretty much obsolete, you can find them on eBay at low prices, so these oscilloclocks could be relatively cheap to build.

In the write up, you get a teardown of the Tek 520A, showing the modifications made to build the clock. After the break, check out a video of the Tek 520A Oscilloclock.

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Help Save Nullspace Labs

January 25, 2014 by Eric Evenchick 54 Comments

A few days ago, the folks at Nullspace Labs in downtown LA got a surprising memo: their building is going to be gutted in a month. With thirty days left, they need money to cover first and last months rent, and help with moving. We can imagine that moving a Hackerspace is no small feat, since they tend to accumulate tons of awesome stuff.

The Hackerspace has started a crowd funding campaign, and has posted a call for help. They are looking for money, new members, or help with moving. If you’ve never been, you can check out our tour of Nullspace Labs.

It’s tough deciding what Hackerspace news to cover. We can’t run individual features on every tip we get promoting Hackerspace events, developments, crowd funding campaigns, and calls for help. We’re featuring this one because we just visited them, they’re awesome, and they’ve also been the source for many great stories over the years, like craning in a laser cutter or developing a modular LED orb. So here’s a question for you: Should we be presenting more Hackerspace news that is perhaps only relevant at the local level? If you think we should, how would we present it? There’s the option of doing occasional links-post-like roundups. But if you have a better idea we’re all ears.

Reverse Engineering An HDMI Extender

January 25, 2014 by Eric Evenchick 63 Comments

There’s a number of devices out there that extend HDMI over IP. You connect a video source to the transmitter, a display to the receiver, and link the two with a CAT5/5e/6 cable. These cables are much cheaper than HDMI cables, and can run longer distances.

[Daniel] didn’t care about extending HDMI, instead he wanted a low cost HDMI input for his PC. Capture cards are a bit expensive, so he decided to reverse engineer an IP HDMI extender.

After connecting a DVD player and TV, he fired up Wireshark and started sniffing the packets. The device was using IP multicast on two ports. One of these ports had a high bitrate, and contained JPEG headers. It looked like the video stream was raw MJPEG data.

The next step was to write a listener that could sniff the packets and spit the data into a JPEG file. After dealing with some quirks, JPEG images could be saved from the remote device. Some more code was needed to have the computer initiate the streaming, and to extract audio from the second port.

In the end, video capture with the low cost device was possible. [Daniel] also provided a bonus teardown of the device in his writeup.

A Meccano Pinball Machine

January 21, 2014 by Eric Evenchick 14 Comments

This pinball table is almost entirely out of Meccano Construction Set parts. [Brian Leach]’s Meccano Pinball Machine features a digit counter, a kick out hole, flippers, and a timer.

The digit counter is likely the most complex part of the build. By sending it an electrical signal, either the ones, tens, or hundreds digit can be incremented. The electrical signal engages an electromagnet, which connects a motor to the wheel to increment the score. A mechanism ensures the next digit is incremented when a digit rolls over from 9 to 0, and allows the counter to be zeroed.

Rolling the ball over the set of rollover switches increments the score. A mechanism is used to ensure that the switch will trigger with a small weight. Arcing was an issue, which was reduced by adding a snubber to suppress the transient.

The pinball machine was demoed at the South East London Meccano Club, and is a great demonstration of what can be built with the construction kit. After the break, check out a video of the pinball machine.

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Microcorruption Embedded CTF

January 18, 2014 by Eric Evenchick 14 Comments

The folks at Matasano Security and Square have teamed up to build an online capture the flag (CTF) competition. The Microcorruption CTF focuses on embedded security and challenges players to reverse engineer a fictional “Lockitall LockIT Pro” lock system.

Each level places you in a debugging environment with a disassembly listing, live memory view, register view, and debugging console. You can set breakpoints, step through code, and modify registers like in a real debugging environment. Your goal is to figure out how to bypass the lock to collect bearer bonds.

While the device and motive may be fictional, the assembly is actual MSP430 code. The debugger is similar to GDB connected to a remote target using OpenOCD. There’s even a manual (PDF) to help you get up to speed with writing MSP430 code for the device.

This CTF looks like a great introduction to embedded security, and doesn’t require buying real hardware. It even includes a full tutorial to get you started.