Fixing tools with 3D printers

saw

Over at the Manchester Hackerspace, [Bob] has been busy getting a 30-year-old bandsaw up and running. The saw worked great, but it was missing a fence, making straight cuts difficult to say the least.  The solution, of course, was to build a new fence, and [Bob] decided to capitalize on his hackerspace’s workshop by making a new fence with a 3d printer.

[Bob] began by taking careful measurements of the saw’s table and the channel running down the length of it. These measurements were plugged into OpenSCAD, and after a few iterations, [Bob] had an extremely well-fitting profile a fence could be attached to.

With the profile down, [Bob] created a new part in OpenSCAD that would hold an aluminum angle piece. This was attached to the plastic parts with screws, and the entire assembly clamps down to the saw with the help of a few 5mm bolts. For a machine that is usually dedicated to making 3D printer parts and Yoda heads, [Bob] did a great job making good use of his 3D printer.

A homebrew binary wristwatch

watch

There are 2 types of people in the world; those who know binary, those who don’t, and those who know ternary. [Emanuele] thought a binary wristwatch is the pinnacle of nerd and set out to build his own. The resulting binary clock not only screams nerd as intended, but is also a functional time piece, as well.

The idea of a binary wristwatch came to [Emanuele] while he was working with PICs at school. Not wanting to let that knowledge go to waste, he used a PIC16F628 microcontroller for this build. There are four LEDs for the hours and six LEDs for the minutes, each attached to a separate microcontroller pin for easy programming.

To keep time, [Emanuele] kept the PIC in sleep mode most of the time, only waking it up when a an internal timer’s register overflows. The watch spends most of its time sleeping, sipping power from a coin cell battery with a battery life that should last weeks, at least.

The entire circuit is tucked away in a PVC enclosure with a wonderful rainbow ribbon cable band. We’re not so sure about how that feels against the skin all day, but it does exude the nerd cred [Emanuele] was looking for.

Rogue Pi: A RPi Pentesting Dropbox

Rogue Pi

A pentesting dropbox is used to allow a pentester to remotely access and audit a network. The device is dropped onto a network, and then sets up a connection which allows remote access. As a final project, [Kalen] built the Rogue Pi, a pentesting dropbox based on the Raspberry Pi.

The Rogue Pi has a few features that make it helpful for pentesting. First off, it has a power on test that verifies that the installation onto the target network was successful. Since the install of a dropbox needs to be inconspicuous, this helps with getting the device setup without being detected. A LCD allows the user to see if the installation was successful without an additional computer or external display.

Once powered on, the device creates a reverse SSH tunnel, which provides remote access to the device. Using a reverse tunnel allows the device to get around the network’s firewall. Aircrack-ng has been included on the device to allow for wireless attacks, and a hidden SSID allows for wireless access if the wired network has issues. There is a long list of pentesting tools that have been built to run on the Pi.

Check out a video demonstration of the dropbox after the break.

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Smoothing 3D Prints with Acetone Vapor

Acetone Smoothed Prints

If you’ve ever used an extruding 3D printer, you know that the resulting prints aren’t exactly smooth. At the Southackton hackerspace [James] and [Bracken] worked out a method of smoothing the parts out using vapor. The method involves heating acetone until it forms a vapor, then exposing ABS parts to the vapor. The method only works with ABS, but creates some good looking results.

Acetone is rather flammable, so the guys started out with some safety testing. This involved getting a good air to fuel mixture of acetone, and testing what the worst case scenario would be if it were to ignite. The tests showed that the amount of acetone they used would be rather safe, even if it caught fire, which was a concern several people mentioned last time we saw the method.

After the break, [James] and [Bracken] give a detailed explanation of the process.

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Hacked Interactive R2D2 controlled by Raspberry Pi

hacked-R2D2-controlled-by-raspberry-pi

Ah R2D2. Probably one of the most recognized little robots on the planet. There have to be a hundred different toys of R2 out there, but one of the more impressive is the 30th Anniversary Interactive edition. Complete with all kinds of bells and whistles, it’s about as realistic as they come. One Star Wars fan found himself in possession of a broken Interactive R2, and with his girlfriend’s birthday coming up, decided to do a little droid surgery to create the ultimate gift.

Giving Anakin a run for his money, all the controls for this R2 unit were custom built.  A Raspberry Pi running Rasbian acts as the brain. Facial recognition was implemented using OpenCV. Voice commands in either English or Chinese were made possible by PocketSphinx. Some of the other features he included are: message recording and playback, ultrasonic distance detection, motion detection, wifi, and a rechargeable battery. Many of those features were included in the original toy, but since this unit was broken, had to be rebuilt from scratch.

In the end, it must have impressed his girlfriend – she’s now his wife. Good work Jedi. Check out some build photos and a video demonstration after the break.

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LiFePO4 batteries work much better in a camera than NiMH

SAMSUNG

We agree with [Zapmaker] that Canon cameras chew through nickel metal hydride batteries. But we’re not going to use Alkaline because we think it’s wasteful. His solution is to use a battery that has a higher voltage rating. What you see here is a single lithium iron phosphate cell paired with a dummy cell to increase life between charges.

The reason that NiMH batteries don’t last very long is that they’re only rated at 2.4V. It won’t take long for that voltage to drop below the camera’s cutoff threshold since they didn’t start very high to begin with. But a single LiFePO4 cell has the same form-factor but produces 3.2V and maintains voltage well through it’s discharge cycle.

The size is right, but using one cell won’t work by itself. He built a filler for the other slot which is just a wood dowel with a screw all the way through it. The point was ground down and a bit of foil added to ensure a proper connection. We’d be interested to hear back about how this performs over the long term.

Shocking Operation makes sure you have skin in the game

operation-shocks-you

Odds are you played the game of Operation when you were a kid. The classic electronic toy challenges you to use a tethered tweezers to extract plastic pieces without touching the sides of the holes they’re hiding in. This upgrade makes the challenge more interesting for a grown-up audience. If you touch the sides you won’t hear a jarring sound, you’ll get a painful shock!

The modification starts by clipping off the melted plastic portions that hold the paperboard face plate on the game. From there the original electronics are completely removed. We think this a bit of a mistake as we’d still like spectators to hear the sound as the player gets a shock. But we digress. The circuit board from a disposable camera is patched into the game. A wrist band forms an electrical connection with your body, providing a path for the camera’s flash capacitor to discharge if you happen to touch the sides with the tweezers.

This write-up is missing one important thing: video of someone getting shocked. [Psycosisnine] promises to add some soon, but for now you’ll just have to fall back on our absolute favorite Mindflex shock project.