The Nickelphone

October 28, 2013 by Marsh 14 Comments

nickelphone

[Tyler Bletsch] sent us a tip about his new build: a keyboard that redefines “coin-operated.” The Nickelphone can emit square wave tones via a piezo buzzer, but [Tyler] made this 25-key piano as a MIDI keyboard capable of driving a full synthesizer.

He chose an ATMega644 as the brain because it’s Arduino-friendly but has more data pins—32—than the usual ATMega328 chip, which allows him to provide each key with its own pin. Each coin was soldered to its own wire and connects up to a 1MΩ resistor array. Coin-presses are recognized by the simple capacitive sensing technique outlined here, but [Tyler] needed to take advantage of a workaround to accurately detect multiple presses.

Check out [Tyler’s] detailed project guide for more information as well as the source code. Check out the video of the Nickelphone after the break, then browse through some other capacitive touch hacks, like the Capacitive Touch Business Card or the Capacitive Touch Game Controller.

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Hacking And Philosophy: An Introduction

October 28, 2013 by Marsh 61 Comments

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This fall marks my third (and Flying Spaghetti Monster willing, final) year as a PhD student, and although I’m no longer taking courses, I often wonder how my seminars might have differed if other hacker-types were in the classroom contributing to the discussion.

Hacking and Philosophy is a new column that explores scholarly research about hacking, and does so with a community that lives the hacking experience. It’s a chance to discuss how researchers and deep thinkers handle our culture, its image, its philosophy, etc. Put simply, think of it as a weekly book club meeting. I’ll choose the text and proceed one chapter at a time, giving you my complete response to that week’s reading while engaging your replies in the comments as well as including your important or insightful contributions in future posts. Further, I promise never to venture into Ivory Tower territory: I hate being talked down to as much as the next person.

Hacking and Philosophy only works if it’s a conversation, so I encourage contributions, corrections, respectful disagreements, and as much hypertext (obviously literally, but philosophically a la Landow) that you can manage. Think of me not as an instructor but as a fellow participant who will occasionally guide us through obscure concepts and terminology.

Keep reading after the break for a tentative book list and the reading for next week!

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Microslice: The Tiny Arduino Laser Cutter

October 27, 2013 by Marsh 37 Comments

[SilverJimmy] already had a full-sized 50 watt laser cutter, but he decided to try his hand at putting together something smaller and microcontroller-driven. The result is this adorable little engraver: the MicroSlice.

To keep the design simple, [SilverJimmy] opted for a fixed cutting table, which meant moving the cutting head and the X-Axis as a unit along the Y-Axis. The solution was to take inspiration from gantry cranes. He snagged a couple of stepper motors with threaded shafts, designed the parts in Inkscape, then fired up his full-size cutter to carve out the pieces. An Arduino Uno and the relays for the laser and fans sit on the MicroSlice’s bottom platform, and two EasyDriver motor controllers sit above them on the next layer.

Swing by the Instructables for more details including the source code, and to see a video of the engraver below. [SilverJimmy] sourced his laser from eBay, but check out the engraver from earlier this year that used a DVD diode.

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[Charles’s] Epic “Total-Recap” GoKart Post

October 27, 2013 by Marsh 11 Comments

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If you’ve built an electric vehicle in the past few years, you probably owe [Charles] a couple of beers. Now you can feel more indebted to him after you read his 17,500-word, 10-part post covering everything you need to know about electric go-kart design. You’ll want to grab a sandwich to keep you company.

You probably recall the Chibikart from posts earlier this summer, which is one of an endless list of EV projects [Charles] has up his sleeve. He’s been teaching MIT students how to build EV karts for a while now, and this total-recap “2.00gokart” novel is [Charles’s] way of sharing the wealth. This is more than a simple how-to guide, though. Instead, it reads like a teacher’s edition of GoKarting 101, with a few brief and important histories, walk-throughs of how the class evolved, exhaustive links to vendors, graphs, videos, and plenty of reference and documentation.

If you have even the slightest interest in electric vehicles, do yourself a favor and give it a browse. There are a couple of videos after the break, and if you need some more motivation, check out the EV skateboard that uses a lot of the same parts.

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Class Up Your Haunted House With A Disney Mansion Prop

October 26, 2013 by Marsh 2 Comments

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Die-hard Disney fan [Brandon Etto] must have one of the coolest houses in the block around this time of year, especially now that he’s built his own Master Gracey changing portrait. If you’re unfamiliar with the Disney Haunted Mansion attraction, there are a few different versions at theme parks around the world; the Orlando one features a portrait above the fireplace that miraculously ages into skeletal form.

[Brandon’s] recreation uses a Raspi loaded with a Video Looper SD image that cycles through a clip of the aging man image. He fabricated a box to hold a 19″ LCD monitor and mounted an inexpensive IKEA frame to the front. The magic is hidden with window film applied to turn the frame’s glass into a two-way mirror: a technique [Brandon] borrowed from this Halloween Instructable.

For a step-by-step tutorial, you’ll want to head over to [Brandon’s] writeup on MAKE, but stick around for a quick video demonstration after the break and check out another Haunted Mansion hack: the Singing Heads.

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Building A Ball-Balancing Robot

October 24, 2013 by Marsh 16 Comments

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If you want a different kind of feedback systems challenge, ditch the Segway-style robots and build one that can balance on a ball. UFactory is a startup in Shenzhen, and this impressive little guy is a way of showing their skills applied to the classic inverted pendulum. At nearly 18 inches tall and weighing just over six pounds, the robot boasts a number of features beyond an accelerometer and gyroscope: it has both a WiFi module and a camera, and can be controlled via a homemade remote control or a Kinect.

The build uses plastic omni-directional wheels attached to 3 brushed dc motors, which attach to the base of the robot with custom-made aluminum brackets. The UFactory gang constructed the robot’s body out of three acrylic discs, which hold the electronics directly above the wheels. The brain seems to be an STM32 microcontroller that connects up to the motors and to the sensors.

You won’t find the code on their Instructable yet, but according to the comments they have plans to make the entire project open source. If you’re desperate for more details, the UFactory team seems willing to provide source code and other information via email. Make sure you see the video after the break, particularly the end where they demonstrate interference and carrying loads. This isn’t the first ball pendulum we’ve seen; take a trip down memory lane with the BallP ball balancing robot from 2010.

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Hacking A Streetlight With Lasers

October 24, 2013 by Marsh 109 Comments

$20, some spare parts and a bit of mischief was a small price for [Chris] to pay for a reprieve from light pollution with this remote control laser hack. The streetlight in front of his house has a sensor that faces westward, and flips the lamp on once the sun has disappeared over the horizon. As it turns out, [Chris’s] third floor window is due west of this particular lamp, meaning he takes the brunt of its illumination but also conveniently places him in a prime location for tricking the sensor.

According to [Chris], the lamp’s sensor requires two minutes of input before it will switch off and stay off for around 30 seconds before cycling on again. The lamp does not zap straight to full brightness, though; it takes at least a minute to ramp up. [Chris] recalled a hack from a few years ago that essentially used LED throwies tacked onto the sensors with putty to shut off lamps for a guerrilla drive-in movie, but the sensors on those lamps were at the base and easily accessed. [Chris] needed to reach a sensor across the block and nearly three stories tall, so he dug around his hackerspace, found a 5V 20mA laser diode, and got to work building a solution.

[Chris] 3D printed a holder for the laser and affixed it via a mounting bracket to the wall near his third floor window, pointing it directly at the street lamp’s sensor. He plugged the laser’s power supply into an inexpensive remote control outlet, which allowed him to darken the street lamp at a touch of a button. This is certainly a clever and impressive hack, but—as always—use at your own risk. Check out a quick demo video after the break.

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