Peculiar Radial Mill from Car Parts

Whether 3D printer, lasercutter, or mill, most CNC machines use human-friendly, square-angle Cartesian geometry. This intriguing concept mill instead uses radial axes where motion is derived from scrap Chevy flywheels. It may look and feel weird at first, but it works – sort of.

Cartesian axes are intuitive. If you want to go to the right, increase X. If you want to go to away from you, increase Y. If you want to lift, increase Z. On a manual mill this is easy for making rectangles and blocks, or, with creative clamping, straight lines of any sort. But if you want to carve a circle? As we all learned on an Etch-A-Sketch, you increase your swearing and then throw it in the corner.

HAD - Radial Mill2[Jason] knew that with a CNC machine all geometry problems are reduced to math done by software. With two offset discs, any position is possible by rotating both the correct way. It may look odd that both plates drunkenly meander about just to draw a straight line but the computer is ambivalent. Software can be complicated without penalty and is free once written – more on that later. If a machine is physically simple then it can be built and repaired easily and cheaply. This design does away with almost all the familiar – and [Jason] argues complicated – components of normal hobby CNC machines. No slides, rails, carriages or belts here. His design uses only about a dozen parts.

Because automotive flywheels are made from cast iron the machine is rigid and naturally dampening. Sticking with the junkyard theme he pulled bearings from an F-450 truck, good for a few thousand pounds. Some steppers and a Raspberry Pi and he was done – well, sort of.

[Jason] let us know that his project has sat for long enough that he has become passionate about other things and decided to move on. He documented his progress and submitted the tip in hope to inspire someone else to continue the design further. Any type of CNC is possible, not just a mill. 3D printer perhaps?

Two big caveats: it needs a Z-axis (linear, probably standard) and there appears to be deeper-seated-than-expected G-code demands to chit-chat about rectangles and only rectangles. Nothing insurmountable, just nothing he has solved yet himself.

[Jason] said not to expect any further updates from him but he would love to see what the next person could do with it.

See the video after the break of the mill drawing our skull and wrenches logo, (soft of, without a Z-axis to lift).

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Reverse Engineering the Kayak Mobile API

The travel meta-search website Kayak apparently used to have a public API which is no longer available. We can’t say we mourn the loss of the interface we’d never known about. If you are someone who was automating their searches for that perfect vacation getaway deal, there’s still hope. But either way you’ll like this one. [Shubhro Saha] figured out how to access the API used by the Kayak mobile app. We like that he details how to sniff the traffic between an app and the internet and make sense of what is found.

His tool of choice is the Python package Mitmproxy. We haven’t heard of it but we have heard of Wireshark and [Shabhro] makes the case that Mitmproxy is superior for this application. As the name suggests, you set it up on your computer and use that box’s IP as the proxy connection for your phone. After using the app for a bit, there is enough data to start deconstructing what’s going on between the app and remote server which which it communicates. We could have a lot of fun with this, like seeing what info those free apps are sending home, or looking for security flaws in your own creations.

[Thanks Juan via Twitter]

Sega Controller Hack Updated for Windows Auto-Launch

Who knew that modern versions of Windows have nixed the option to auto-launch when a USB drive is inserted? Not a big deal unless, like [sonicdude10], you want to base a hack on the behavior. He did find a workaround and recently built a Sega Controller emulator to autoplay on Windows computers.

The bulk of the hack was inspired by a Sega Emulator built in a controller which he saw on Hackaday a couple of years back. It’s simply a Sega-like USB gamepad which has a hub and thumb drive internalized. The hardware changes on [sonicdude10’s] version gets rid of the old thumb drive and replaces it with one that supports U3. This is a hardware emulation trick supported by some USB drives which allows them to enumerate as CD drives instead of USB mass storage. Autoplay for CD drives is still functional in Windows.

We’ve heard a bit about U3 over the years. There was a now-dead hack covered all the way back in 2006. And we even found a comment suggesting its use for USB-based game emulators. [sonicdude10] points to two useful tools that let him customize how U3 performs. u3_tool is a multitool for tweaking how the hardware behaves, u3-autorun makes customization of the auto-launching app a snap.

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Trinket EDC Contest: USB Calipers

[Lou]’s entry for the Trinket EDC Contest is a great addition to the ubiquitous digital calipers found on workbenches and eBay resellers the world over. It translates the value displayed on the calipers to a USB HID interface for logging all those tricky measurements at the push of a button.

Most of the digital calipers you’ll find at Harbor Freight or on eBay are pretty much the same. There are two pads on the caliper’s PCB that give any microcontroller the ability to read what is being measured. It’s done with a 24-bit encoding scheme, where each bit is a nearly-BCD measurement in units of 1/1000 of an inch or 1/100 of a millimeter. After decoding the value, [Lou]’s trinket sends a few numbers to a computer over a USB HID interface.

Simply sending a measurement to a computer over USB wasn’t enough for [Lou]. He added three buttons to the project for typing multiple characters. The first button just sends Enter to the computer, the second sends a comma, and the third sends “/2 (Enter)”, exactly what you need to input the radius of something when measuring the diameter.

This was a project for the Trinket EDC Contest that ended a few hours ago. Nobody knows who the winner is, but there are some pretty cool prizes up for grabs including the new Rigol scope, a Fluke 179, and a soldering station.

Shower Occupancy Sensor Keeps Peace/Eliminates Odor at the Office

When the first two prototype ingredients listed are paperclips and Post-it notes you know it’s going to be good. The problem: one shower stall at work with numerous co-workers who bike to the office. The solution: a occupancy monitor that is smart enough to know that someone is actually in the room. You know what we’re talking about, a sensor that knows more than whether the door is open or closed. [James] got wise and built a sensor to monitor whether the door is bolted or not. We think this method is far superior to motion-based systems.

This uber-smart sensor is simply a pair of paperclips anchored on a rolled Post-it note substrate and shoved in the receiver on the door jamb. When the bolt is locked from the inside it pushes the paperclips together completing the simple circuit. This is monitored by a Spark Core but will work with just about any monitoring system you can devise. What we’re trying to figure out is how to ruggedize the paper-clip hack which we can’t think will perform well for very long. It looks like there’s room to bore out a bit more inside the receiver hole. Perhaps leaf switch with a 3D printed mounting bracket?

Oh, and kudos on the Ikea food storage container for the enclosure. That’s one of our favorite tricks for hacks which are installed for the long-run.

Holiday Cheer From The ATtiny13

There are smaller microcontrollers than the ATtiny13. Some ARM chips will fit on the head of a large pin, and even in Atmel world, the ATtiny10 comes in a tiny SOT-23-6 package – a size normally reserved for surface mount transistors. The ‘tiny13, though, can be programmed with just about any ISP and comes in an 8-pin DIP. It’s the bare minimum if you’re looking to break out of the world of Arduino, and you can do some pretty cool things with it, like playing some holiday audio with an SPI Flash chip.

[Vinod] tried opening up a cheap camera pen, but in the course of disassembly a few traces broke. He was now left with a 4Mbit SPI Flash chip. This was obviously the time to investigate what could be done with a small microcontroller and a huge amount of Flash. and the Attiny13 audio player was born.

The circuit uses one PWM for audio out, and reads audio directly from the Flash chip. The UART on board the ‘tiny13 is used to update the Flash, and there’s also a switch to select between play and record. If you’re counting, that means there are 4 pins for the Flash, 2 pins for the UART, 1 for the switch, one for the audio output, and the power and ground rails, all in an 8-pin package. That’s a pretty cool way to use one pin for two different functions.

You can check out a video of the project in action below.

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The Ultimate Tool Cart

[Burning Becks] set out on a quest to build the ultimate tool cart for himself, and we have to admit, what he’s come up with is pretty damn cool. Not only is the cart super organized and functional, it has an integrated fingerprint scanner to unlock one door, a keypad to unlock another drawer, an RFid tag to unlock another… and an RF remote too. Excessive? Perhaps. But hey, what if you accidentally burn off all your finger prints while building a hotplate SMD reflow oven? It’s possible!

To build the ultimate tool cart, [Becks] had to do some research. Specifically research right here at Hackaday, since we love covering unique work benches and tool boxes. He’s taken a few ideas from some of our favorite work space hacks like the computer tower toolbox, a cyclist’s bicycle workshop (yes it’s actually mounted on the bicycle!), a travelling electronics lab, and of course the mobile soldering workstation that sets up quickly and lets you get to work fast.

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