The Nickelphone

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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Microslice: The Tiny Arduino Laser Cutter

[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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Fire Breathing Jack-O-Lantern Of Death

[Rick] is at it again, this week he has conjured up an even more dangerous Halloween hack. Thankfully [Rick] has included a warning of just how dangerous this hack can be, especially if children are around. Don’t do this hack unless you know what you’re doing and you can do it safely.

For [Rick]’s number four hack of the month he gives us the Fire Breathing Jack-O-Lantern of death! This isn’t a new idea but it is a very unique and simple implementation. We always love seeing the ingenuity of hackers to repurpose existing commercial products. In this case, [Rick] uses an automated air freshener which dispenses a flammable spray for the pumpkins breath if you dare get too close, but not so close as to get burned. The trigger distance is controlled by an Arduino and a Parallax Ping))) sensor so as to fire only when people are farther than 3 feet but closer than 5 feet. You can get a copy of the Arduino sketch from his blog posting.

A small candle is used to ignite the flammable spray, which shoots out 5 to 10 inches from the pumpkin’s mouth when triggered by the ultrasonic sensor. It couldn’t be simpler. The most challenging part was getting the large air freshener dispenser in the pumpkin with the flames coming out the mouth. A little extra whacking at the pumpkin fixed the fit, but planning for a larger pumpkin would be advised.

Theoretically the Arduino shouldn’t trigger and throw flames if people are too close, but when kids are running around they may come right into the target area unexpectedly. If this hack is used in the right place it would make for a great Halloween display item and could be used safely.

After the break you can watch [Rick’s] flame breathing Jack-o-Lantern build tutorial.

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Arduino-Controlled Single-Leaf Shutter

Single-Leaf Shutter

[Kevin] has made an interesting camera shutter mechanism using an Arduino and a solenoid. To keep it extremely simple, he is only controlling a single leaf. In the linked video, you can see him take it through its paces from 1/125 seconds up to infinite. This is, of course, a proof of concept, and [Kevin] mentions using smaller components to make everything fit easily inside a Holga-like body. As he points out in the video’s comments, digitally controlling the flash would be a simple matter as well.

A basic camera is incredibly simple to make, and [Kevin’s] design certainly isn’t complicated. That said, if you look at the big picture, [Kevin] is demonstrating how feasible it could be to build an entirely custom camera with a standard microcontroller as the brain. We can’t help but think of all of the possibilities when you are able to control the entire photo taking process.

Interestingly, [Kevin] is also behind this twin lens reflex Kickstarter project from earlier in the year. It will be interesting to see what other camera-related hacks we will see from him.

Easy-phi: An Open Source Platform For Experimenters

As a few of Hackaday readers may already know, my day job involves working with high speed electronics. For the last few months, my team at [Université de Genève] in Switzerland has been working on an open source platform (mostly) targeted for experimenters: the easy-phi project. The main idea is to build a simple, cheap but intelligent open hardware/software platform consisting of a 19″ frame (or smaller), which can house a big variety of electronic modules. Hobbyist would therefore only make/buy the modules that would suit their needs and control them through a web page / standalone application / Labview module.

I detailed in more depth on my website the technical aspects of the project. To give you a quick and simple overview, the rack is essentially a USB hub that connects all the modules to a Cubieboard. It also integrates a few synchronization signals, a clock and a monitoring system for voltages, temperatures, power consumption. The modules are made of template + module specific electronics. The template electronics are part of the ‘easy-phi standard’, they consist of the Arduino compatible SAM3X8E microcontroller and of a few other power related components. This ensures electrical and firmware compatibility between the rack and modules that you guys may develop. It is important to note that the modules are enumerated on the USB bus as composite CDC (communication device) and MSC (mass storage). The CDC is used to configure the module while the MSC allows you to grab its documentation, resources, and standalone application in case you use the module without the rack.

The chosen schematics / layout software is Kicad, and all current files can be found on our github. Others will be uploaded once we have tested the other modules currently in the pipe. As the ones we’re developing are physics oriented, we hope that enthusiasts will bring easy-phi to other domains. Don’t hesitate to contact us if you have any question or if you’d like to contribute.

Turn A PC On With A Knock And An ATTiny

knockAttiny

Pressing the power button on your computer usually isn’t too much trouble, unless your computer is stored away somewhere hard to reach. [Joonas] has been hard at work on a solution that would also impress his friends, building a knock sensor to turn on his PC.

For around $10 in parts he put together an ATTiny45 that emulates a PS/2 device, which takes advantage of his computer’s ability to boot upon receiving PS/2 input. The build uses a Piezo buzzer and a 1M Ohm resistor as a knock sensor exactly as the official Arduino tutorial demonstrates, and one of those PS/2-to-USB adapters that are most likely lurking in the back corner of every drawer in your office.

[Joonas] used AVRweb to disable the 8X clock divider so there’d be enough clock cycles for PS/2 communication, then loaded some test code to make sure the vibrations were being detected correctly. You can check out his Github for the final code here, and stick around after the break for a quick video demo. Then check out a similar hack with [Mathieu’s] home automation knock sensor.

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Pet Water Warden

This weekend’s Make project is a great one for pet owners — an automatic water bowl refilling device!

It’s a fairly simple build, utilizing an old water jug, an Arduino, an aquarium pump, and some home-made water sensors. As always, MAKE has a very thorough guide, and the estimated build time is only an hour or two. They even threw in the ability to Tweet it’s status, including when the reservoir is empty.

But are we over-complicating this? A gravity based water feeder using the jug could work just as well. Sure, you wouldn’t get Twitter updates, but we hope you’re around your pets long enough to know when they’re thirsty.

A more refined version of this could include a solenoid water valve tapped into your house, eliminating the need of the reservoir and making this project a bit more useful. But even that might be a bit much, do we really need the Arduino?  What about a spring-loaded water bowl that breaks a contact when the bowl is empty? Hook that up to a 5 second timer relay controlling the water valve, and you’ve simplified the project quite a bit!

After the break, check out the video to get some more ideas!

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