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Tales Of A Cheap Chinese Laser Cutter

February 22, 2017 by 51 Comments

The star turn of most hackspaces and other community workshops is usually a laser cutter. An expensive and fiddly device that it makes much more sense to own collectively than to buy yourself.

This isn’t to say that laser cutters are outside the budget of the experimenter though, we’re all familiar with the inexpensive table-top machines from China. Blue and white boxes that can be yours for a few hundred dollars, and hold the promise of a real laser cutter on your table.

Owning one of these machines is not always smooth sailing though, because their construction and choice of components are often highly variable. A thorough check and often a session of fixing the non-functional parts is a must before first power-on.

[Extreme Electronics] bought one, and in a series of posts documented the process from unboxing to cutting. Starting with a full description of the machine and what to watch for out of the box, then a look at the software. A plugin for Corel Draw was supplied, along with a dubious copy of Corel Draw itself. Finally we see the machine in operation, and the process of finding the proper height for beam focus by cutting an inclined plane of acrylic.

The series rounds off with a list of useful links, and should make interesting reading for anyone, whether they are in the market for a cutter or not.

These cutters/engravers have featured here before many times. Among many others we’ve seen one working with the Mach3 CNC software, or another driven by a SmoothieBoard.

Interview: Nacer Chahat Designs Antennas For Mars CubeSats

February 22, 2017 by 31 Comments

You have a shoe box sized computer that you want to use in a Mars fly by. How do you communicate with it? The answer is a very clever set of antennas. I got to sit down with Nacer Chahat, one of the engineers on the Jet Propulsion Laboratory team responsible for antenna design on Mars Cube One (MarCO). Two of these CubeSats that will soon be used to help a lander reach Mars. We talked about the work that went into MarCO, the deployable radar antenna he’s worked on for the RainCube project, and the early progress on OMERA, the One Meter Reflectarray.

This is a fascinating discussion of dealing with a multitude of engineering challenges including lack of available space for the antenna components, and power and weight limitations. Check out the video interview to see how the people at JPL fit it all into this, and other tiny satellites, then join us below for more details.

Continue reading “Interview: Nacer Chahat Designs Antennas For Mars CubeSats” →

Ask Hackaday: Is Owning A 3D Printer Worth It?

February 21, 2017 by 132 Comments

3D printers are the single best example of what Open Hardware can be. They’re useful for prototyping, building jigs for other tools, and Lulzbot has proven desktop 3D printers can be used in industrial production. We endorse 3D printing as a viable tool as a matter of course around here, but that doesn’t mean we think every house should have a 3D printer.

Back when Bre was on Colbert and manufacturing was the next thing to be ‘disrupted’, the value proposition of 3D printing was this: everyone would want a 3D printer at home because you could print plastic trinkets. Look, a low-poly Bulbasaur. I made a T-rex skull. The front page of /r/3Dprinting. Needless to say, the average consumer doesn’t need to spend hundreds of dollars to make their own plastic baubles when WalMart and Target exist.

The value proposition of a 3D printer is an open question, but now there is some evidence a 3D printer provides a return on its investment. In a paper published this week, [Joshua Pearce] and an undergraduate at Michigan Tech found a 3D printer pays for itself within six months and can see an almost 1,000% return on investment within five years. Read on as I investigate this dubious claim.

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A Full Speed, Portable Apple //e

February 21, 2017 by 21 Comments

A while back, [Jorj] caught wind of a Hackaday post from December. It was a handheld Apple IIe, emulated on an ATMega1284p. An impressive feat, no doubt, but it’s all wrong. This ATapple only has 12k of RAM and only runs at 70% of the correct speed. The ATapple is impressive, but [Jorj] knew he could do better. He set out to create the ultimate portable Apple IIe. By all accounts, he succeeded.

This project and its inspiration have a few things in common. They’re both assembled on perfboard, using tiny tact switches for the keyboard. The display is a standard TFT display easily sourced from eBay, Amazon, or Aliexpress. There’s a speaker for terribad Apple II audio on both, and gigantic 5 1/4″ floppies have been shrunk down to the size of an SD card. That’s where the similarities end.

[Jorj] knew he needed horsepower for this build, so he turned to the most powerful microcontroller development board he had on his workbench: the Teensy 3.6. This is a 180 MHz ARM Cortex M4 running a full-speed Apple IIe emulator. Writing a simple 6502 emulator is straightforward, but Apple IIe emulation also requires an MMU. the complete emulator is available in [Jorj]’s repo, and passes all the tests for 6502 functionality.

The project runs all Apple II software with ease, but we’re really struck by how simple the entire circuit is. Aside from the Teensy, there really isn’t much to this build. It’s an off-the-shelf display, a dead simple keyboard matrix, and a little bit of miscellaneous circuitry. It’s simple enough to be built on a piece of perfboard, and we hope simple enough for someone to clone the circuit and share the PCBs.

The Elements Converge For ±.002 In Tolerance

February 20, 2017 by 51 Comments

What can be accomplished with just a torch and compressed air? We can think of many things, but bringing a 17-foot-long marine shaft into ±.002 in tolerance was not on our list.

Heat straightening (PDF) utilizes an oxy-acetylene flame that is used to quickly heat a small section of a workpiece. As the metal cools, it contracts more than it expanded when heated, resulting in a changed volume. With skill, any distortions on a shaft can theoretically be straightened out with enough time (and oxy-acetylene). Heat straightening is commonly applied to steel but works on nickel, copper, brass and aluminum additionally.

[Keith Fenner’s] standard process for trueing stock is sensitive enough that even sunlight can introduce irregularities, but at the same time is robust enough to carry out in your driveway. However, even though the only specialty tools you need are a torch, compressed air and work supports, watching [Keith] work makes it clear that heat straightening is as much an art as it is a science. Check out his artistry in the video below the break. Continue reading “The Elements Converge For ±.002 In Tolerance” →

Homemade Subaru Head Unit Is Hidden Masterpiece

February 20, 2017 by 30 Comments

The Subaru BRZ (also produced for Toyota as the GT86) is a snappy sportster but [megahercas6]’s old US version had many navigation and entertainment system features which weren’t useful or wouldn’t work in his native Lithuania. He could have swapped out the built in screen for a large 4G Android tablet/phone, but there’s limited adventure in that. Instead, he went ahead and built his own homemade Navigation system by designing and integrating a whole bunch of hardware modules resulting in one “hack” of an upgrade.

The system is built around a Lenovo 4G phone-tablet running android and supporting GPS, GLONASS as well as the Chinese BeiDou satellite navigation systems. He removed the original daughter board handling the USB OTG connection on the tablet, and replaced it with his version so he could connect it to his external USB board via a flat ribbon cable. The USB board contains a Cypress 4-port USB hub. One port is used as the USB HID device to allow external buttons for system control — Power, Volume Up/Down, Fwd/Rev, Play/Pause, and Phone Answer/Hangup. The second port is used as a regular USB input to allow connecting external devices such as flash drives. The third one goes to a reversing camera while the fourth port goes to a USB DAC.

The USB DAC is another hardware board by itself and also includes a Bluetooth module which integrates his phone’s audio and control functions with the on-board system. There’s also an audio mixer which allows him to use the phone audio without having to miss out on the navigation prompts from the tablet. Both boards also contain several peripheral circuits such as amplifiers and DC power supplies. Audio to the speakers is routed through six LM3886 based power amplifier boards. And the GPS module receives its own special low-noise amplifier board to ensure extremely strong reception at all times. That’s a total of ten boards custom built for this project. He’s also managed to source all the original harness connectors so his system is literally a snap in replacement. The final assembly looks pretty dashing.

For some strange reason, the Lenovo tablet uses 4.35V as the ‘fully charged” value for its LiPo instead of the more common 4.20V, so even with the whole system connected to a hefty 12V lead acid battery from which he’s deriving the 4.20V charging voltage for the tablet, it still complains about “low battery” — and he’s looking for advice on how he can resolve that issue short of blowing up the LiPo by using the higher charge voltage. Besides that, he’s (obviously a kickass) hardware designer and a little bit rusty on the software and programming side of things, for which he’s looking for inputs from the community. His introductory video is almost 30 minutes long, but the shorter demo video after the break shows the system after installation in his car. He’s posted all of his Altium hardware source files on the project page, but until he shares PDF versions, it would be difficult for most of us to look at his work.

Continue reading “Homemade Subaru Head Unit Is Hidden Masterpiece” →

HackBusting: Can You Fake A TV Remote With A Lighter And Some Paper?

February 20, 2017 by 62 Comments

We recently published an article where someone apparently controlled their TV by simulating a remote with merely a lighter and a sheet of paper. The paper had a barcode like cutout for a supposed “Universal Standby Signal”. The video rightfully attracted a substantial crowd, some awestruck by its simplicity, others sceptical about its claims.

Coming from some generic “Viral Life Hack” production house, the characteristic blare of background music, more suited to an underground rave than a technical video, certainly did not do it any favours. As any moderately experienced campaigner would know, modern televisions and remotes have been carefully engineered  to prevent such mishaps. Many of us at Hackaday, were under the impression that it would take something slightly more sophisticated than a fluorescent-bodied lighter and a crisp sheet of A4 to deceive the system. So we tested it out. Our verdict? Unlikely, but not impossible. (And we’re pretty sure that the video is a fake either way.) But enough speculation, we’re here to do science.

Continue reading “HackBusting: Can You Fake A TV Remote With A Lighter And Some Paper?” →