Turning The Makerbot Into A Tattoo Machine


ENSCI les Ateliers, the famous design school in Paris, had a “Public Domain Remix” and hackathon recently, with teams splitting up to remix public domain and other free-to-use IP in projects. Most of the teams came up with similar ideas, but one team went above and beyond the call of duty; they turned a 3D printer into a tattoo machine, capable of inking a real, live human test subject.

The build began by plotting a circle with a pen onto a piece of paper. This evolved into printing a tool holder for a tattoo machine graciously provided by an amateur tattoo artist. Tests with “artificial skin” (any one care to hazard a guess at what that is?) were promising, and the team moved on to a human guinea pig.

The biggest problem the team faced is that humans aren’t flat. They tried a few tricks to tighten the skin around the area to be tattooed – metal rings, elastics, and finally the inner tube from a scooter. In the end, the team was able to tattoo a small circle on the forearm of the test subject.

It’s an extremely simple and small tattoo, and scaling this build up to a sleeve would be difficult. A better solution would be to create a point cloud of an arm before going for a much larger tattoo.

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The Tiny, Awesome Class D Amp


In one of [Hans Peter]‘s many idle browsing sessions at a manufacturer’s website, he came across a very cool chip – a 10 Watt class D amplifier chip. After the sample order arrived, he quickly put this chip in a box and forgot about it. A year or so later, he was asked to construct a portable boom box kit for a festival. Time to break out that chip and make a small amplifier, it seems.

The chip in question – a Maxim MAX9768 – is a tiny chip, a 24-pin TQFP with 1mm pitch. Hard to solder freehand, but this chip does have a few cool features. It’s a filterless design, very easy to implement, and perfect for the mono boombox project he was working on. A simple, seven component circuit was laid out on a breadboard and [Hans] got this chip up and running.

For the festival, a breadboarded circuit wouldn’t do. He needed a better solution, something built on a PCB that would work well as a kit. The requirements included the MAX9768 chip, a guitar preamp, stereo to mono summing, and through-hole parts for easy soldering. The completed board ended up being extremely small - 33.6mm by 22.5mm – and works really great.

After the festival, [Hans] found a 20 Watt chip and designed an all-SMD version of the board. Just the thing if you ever want to stuff a tiny amplifier into a crevice of a project.

Dispensing Solder Paste With A 3D Printer


There’s a strange middle ground in PCB production when it comes to making a few boards. Dispensing solder paste onto one board is easy enough with a syringe or toothpick, but when pasting up even a handful of boards, this method gets tiresome. Solder paste stencils speed up the process when you’re doing dozens or hundreds of boards, but making a stencil for just a few boards is a waste. The solution for this strange middle ground is, of course, to retrofit a 3D printer to dispense solder paste.

This project was a collaboration between [Jake] and [hzeller] to transform KiCAD files to G Code for dispensing solder paste directly onto a board. The machine they used was a Type A Machines printer with a solder paste dispenser in place of an extruder. The dispenser is hooked up to the fan output of the controller board, and from the looks of the video, they’re getting pretty good results for something that’s still very experimental.

All the code to turn KiCAD files into G Code are up on [hzeller]‘s github. If you’re wondering, the board they’re pasting up is a stepper driver board for the BeagleBone named Bumps.

Videos below.

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Reverse Engineering Programmable Logic


Despite what the cool kids are doing over on Hackaday Projects, the vast majority of vintage computers used some form of programmable logic for memory control, address decoding, and all that other stuff that can be done with just a few logic chips. It’s a great way to design a product for production, but what happens when the programmable chips go bad after 30 years?

[Clockmeister] got his hands on a Dick Smith VZ300 computer (a clone of the VTech Laser 310) with two broken 40-pin custom chips. After going through the schematics and theory of operation for this compy, he recreated the custom chips in 74 series logic.

The Dick Smith VZ300 is a fairly standard piece of equipment from 1985 – a Z80 CPU, 16k RAM, upgradable to 64k, a tape drive, and 32×16 character, 8 color display. Inside this computer are two 40-pin chips that are responsable for video buffering and VRAM control, keyboard and cassette I/O, video timing, and the monophonic speaker decoding. Both of these chips failed, and spares are unavailable, apart from scavenging them from another working unit.

After careful study, [Clockmeister] recreated the circuits inside these chip with 74 series logic chips. The new circuit was built on a board that plugs directly into the empty 40-pin sockets. Everything in this rehabbed computer works, so we’re just chalking this up as another reason why designing new retrocomputers with programmable logic is a dumb idea. Great for a product, but not for a one-off.

Image source


Editing Circuits With Focused Ion Beams


[Andrew] has been busy running a class on hardware reverse engineering this semester, and figured a great end for the class would be something extraordinarily challenging and amazingly powerful. To that end, he’s editing CPLDs in circuit, drilling down to metal layers of a CPLD and probing the signals inside. It’s the ground work for reverse engineering just about every piece of silicon ever made, and a great look into what major research labs and three-letter agencies can actually do.

The chip [Andrew] chose was a Xilinx XC2C32A, a cheap but still modern CPLD. The first step to probing the signals was decapsulating the chip from its plastic prison and finding some interesting signals on the die. After working out a reasonable functional diagram for the chip, he decided to burrow into one of the lines on the ZIA, the bus between the macrocells, GPIO pins, and function blocks.

Actually probing one of these signals first involved milling through 900 nm of silicon nitride to get to a metal layer and one of the signal lines. This hole was then filled with platinum and a large 20 μm square was laid down for a probe needle. It took a few tries, but [Andrew] was able to write a simple ‘blink a LED’ code for the chip and view the s square wave from this test point. not much, but that’s the first step to reverse engineering the crypto on a custom ASIC, reading some undocumented configuration bits, and basically doing anything you want with silicon.

This isn’t the sort of thing anyone could ever do in their home lab. It’s much more than just having an electron microscope on hand; [Andrew] easily used a few million dollars worth of tools to probe the insides of this chip. Still, it’s a very cool look into what the big boys can do with the right equipment.


Raspberry Pi Quake III Bounty Claimed


For the Raspberry Pi’s second birthday, the Raspi foundation gave us all a very cool gift. Broadcom released the full documentation for the graphics on one of their cellphone chips and offered up a $10k prize to the first person to port that code over to the graphics processor on the Pi and run Quake III. The prize has been claimed, forming the foundation for anyone wanting a completely documented video core on the Pi.

The person to claim this prize is one [Simon Hall], author of the DMA module that’s in the current Raspbian release. Even though Quake III already runs on the Pi, it does so with a closed source driver. [Simon]‘s work opens up the VideoCore in the Pi to everyone, especially useful for anyone banging their heads against the limitations of the Pi platform.

You can get your hands on the new video drivers right now, simply by downloading and compiling all the sources. Be warned, though: recompiling everything takes around 12 hours. We’re expecting a Raspbian update soon.


A Real Malware In A Mouse


After reading an April Fools joke we fell for, [Mortimer] decided to replicate this project that turns the common USB mouse into a powerful tool that can bring down corporations and governments. Actually, he just gave himself one-click access to Hackaday, but that’s just as good.

The guts of this modified mouse are pretty simple; the left click, right click, and wheel click of the mouse are wired up to three pins on an Arduino Pro Micro. The USB port of the ‘duino is configured as a USB HID device and has the ability to send keyboard commands in response to any input on the mouse.

Right now, [Mortimer] has this mouse configured that when the left click button is pressed, it highlights the address bar of his browser and types in http://www.hackaday.com. Not quite as subversive as reading extremely small codes printed on a mousepad with the optical sensor, but enough to build upon this project and do some serious damage to a computer.

Video of [Mort]‘s mouse below.

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