Tales Of A Cheap Chinese Laser Cutter

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.

From Zero to Nano

Have you ever wanted to build your own Arduino from scratch? [Pratik Makwana] shares the entire process of designing, building and flashing an Arduino Nano clone. This is not an entry-level project and requires some knowledge of soldering to succeed with such small components, but it is highly rewarding to make. Although it’s a cheap build, it’s probably cheaper to just buy a Nano. That’s not the point.

The goal here and the interesting part of the project is that you can follow the entire process of making the board. You can use the knowledge to design your own board, your own variant or even a completely different project.

from-zero-to-nano-thumb[Pratik Makwana] starts by showing how to design the circuit schematic diagram in an EDA tool (Eagle) and the corresponding PCB layout design. He then uses the toner transfer method and a laminator to imprint the circuit into the copper board for later etching and drilling. The challenging soldering process is not detailed, if you need some help soldering SMD sized components we covered some different processes before, from a toaster oven to a drag soldering process with Kapton tape.

Last but not least, the bootloader firmware. This was done using an Arduino UNO working as master and the newly created the Arduino Nano clone as target. After that you’re set to go. To run an actual sketch, just use your standard USB to UART converter to burn it and proceed as usual.

Voilá, from zero to Nano:

Continue reading “From Zero to Nano”

Harmonographs Generate Geometric Images Unique as Fingerprints

When my elder brother and I were kids back in the late 1970’s, our hacker Dad showed us this 1960-61 catalog of the Atlas Lighting Co (later Thorn Lighting) with an interesting graphic design on the cover. He told us to do a thought experiment, asking us to figure out how it would be possible to have a machine that would draw the design on that catalog cover.

Incorrectly, our first thought was that the design was created with a Spirograph. A spirograph has two main parts: a large ring with gear teeth on the inside and outside circumferences and a set of smaller, toothed wheels with holes in them for inserting a drawing instrument — usually a ball point pen. You hold the big ring, insert the pen in the smaller wheel, and then mesh and rotate the smaller wheel around the big ring. But spirographs can’t be used to draw irregular, asymmetrical figures. You could always recreate a design. Because of the nature of gears, none of them were unique, one off, designs.

A spirograph set like this cannot make the image above[Image credit: Multicherry CC-BY-SA 3.0]
A spirograph set like this cannot make the image above [Image credit: Multicherry CC-BY-SA 3.0]
We figured adding some lever arms, and additional geared wheels (compound gears) could achieve the desired result. It turns out that such a machine is called a Cycloid Drawing Machine. But even with this kind of machine, it was possible to replicate a design as often as required. You would fix the gears and levers and draw a design. If the settings are not disturbed, you can make another copy. Here’s a video of a motorized version of the cycloid machine.

The eventual answer for making such designs was to use a contraption called as the harmonograph. The harmonograph is unique in the sense that while you can make similar looking designs, it would be practically impossible to exactly replicate them — no two will be exactly the same. This thought experiment eventually led to my brother building his own harmonograph. This was way back when the only internet we had was the Library, which was all the way across town and not convenient to pop in on a whim and fancy. This limited our access to information about the device, but eventually, after a couple of months, the project was complete.

Continue reading “Harmonographs Generate Geometric Images Unique as Fingerprints”

Friday Hack Chat: Security for IoT

securityforiot-01Over the last few weeks, our weekly Hack Chats on hackaday.io have gathered a crowd. This week, we’re talking about the greatest threat humanity has ever faced: toasters with web browsers.

The topic of this week’s Hack Chat is Security for IoT, because someone shut down the Internet with improperly configured webcams.

This chat is hosted by the Big Crypto Team at the University of Pittsburgh. [Wenchen Wang], [Ziyue Sun], [Brandon Contino], and [Nick Albanese] will be taking questions about lightweight devices connected to the Internet. Discussion will include building things that connect to larger networks securely.

The Big Crypto team at UP are thinking about the roadblocks people have to implement security in their projects, and if apathy or ignorance is the main reason security isn’t even considered in the worst IoT offenders.

The Hack Chat is scheduled for Friday, February 24th at noon PST (20:00 GMT).

Here’s How To Take Part:

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging.

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Upcoming Hack Chats

These Hack Chats are becoming very popular, and that’s due in no small part to the excellent lineup of speakers we’ve hosted. Already, we’ve had [Lady Ada], [Sprite_tm], and [bunnie] — engineers, hackers, and developers who are at the apex of their field. We’re not resting on our laurels, though: in a few weeks we’ll be hosting Hack Chats with [Roger Thornton], an engineer with Raspberry Pi, and Fictiv, masters of mechanical manufacturing.

MicroVox Puts the 80’s Back into Your Computer’s Voice

[Monta Elkins] got it in his mind that he wanted to try out an old-style speech synthesizer with the SC-01 (or SC-01A) chip, one that uses phonemes to produce speech. After searching online he found a MicroVox text-to-speech synthesizer from the 1980s based around the chip, and after putting together a makeshift serial cable, he connected it up to an Arduino Uno and tried it out. It has that 8-bit artificial voice that many of us remember fondly and is fairly understandable.

The SC-01, and then the SC-01A, were made by Votrax International, Inc. In addition to the MicroVox, the SC-01 and SC-01A were used in the Heath Hero robot, the VS-100 synthesizer add-on for TRS-80s, various arcade games such as Qbert and Krull, and in a variety of other products. Its input determines which phonemes to play and where it shines is in producing good transitions between them to come up with decent speech, much better than you’d get if you just play the phonemes one after the other.

microvox-manualThe MicroVox has a 25-pin RS-232 serial port as well as a parallel port and a speaker jack. In addition to the SC-01A, it has a 6502 under the hood. [Monta] was lucky to also receive the manual, and what a manual it is! In addition to a list of the supported phonemes and words, it also contains the schematics, parts list and details for the serial port which alone would make for fun reading. We really liked the taped-in note seen in this screenshot. It has a hand-written noted that says “Factory Corrected 10/18/82”.

Following along with [Monta] in the video below, he finds the serial port’s input buffer chip datasheet online and verifies the voltage levels. Next he opens up the case and uses dips switches to set baud rate, data bits, parity, stop bits and so on. After hooking up the speakers, putting together a makeshift cable for RX, TX and ground, and writing a little Arduino code, he sends it text and out comes the speech.

Continue reading “MicroVox Puts the 80’s Back into Your Computer’s Voice”

Interview: Nacer Chahat Designs Antennas for Mars CubeSats

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”

T-Rex Runner Runs on Transistor Tester

If you’ve ever spent time online buying electronic doodads — which would mean almost all of us — then sooner or later, the websites get wind of your buying sprees and start offering “suggested” advertisements for buying more useless stuff. One commonly offered popular product seems to be a universal component tester, often referred to as a “Mega328 Transistor Tester Diode Triode Capacitance ESR Meter”. These consist of an ATmega328, an SPI LCD display, a Button, a ZIF socket and a few other components. Almost all of them are cheap clones of the splendid AVR-TransistorTester project by [Markus Frejek]. [Robson Couto] got one of these clone component testers, and after playing with it for a while, decided to hack it and write a T-Rex runner game for it.

The T-Rex runner game is Chrome’s offering for you to while away your time when it can’t connect to the internet. It needs just one button to play. This is just the kind of simple game that can be easily ported to the Component Tester. The nice take away from [Robson]’s blog post is not that he wrote a simple game for an ATmega connected to an LCD display, but the detailed walk through he provides of the process which can be useful to anyone else wanting to dip their feet in the world of writing games.

After a bit of online sleuthing and some multimeter testing, he was able to figure out that the LCD controller chip was connected to Port D of the ATmega, which meant the use of software SPI via bit-banging. He then looked inside the disassembled firmware to find writes to Port D to figure out pin assignments. Of course not long after all this work he found a config.h file with the pin mappings.

Armed with this information he was able to use the Adafruit ST7565 library to drive the LCD, but not before having to flip the image. The modified fork of his ST7565 library is available on GitHub. His game code is also available, but reading through the development process is pretty interesting. Check out a video of the Runner game in action after the break.

In an earlier post, we did a product review of one of these cheap Transistor Testers, and if you have one of these lying around, give [Robson]’s game a spin — it could be handy while you wait for your reflow oven to finish its soldering cycle.

Continue reading “T-Rex Runner Runs on Transistor Tester”