Year: 2012

Replacing A Finger Or An Arm In The Hacker Tradition

August 31, 2012 by 33 Comments

Just a few weeks ago we were wondering if we’d try to build our own prosthesis if we were ever to lose a limb. This pair of hacks answers that query with a resounding “YES!”.

To the right is a replacement pointer finger. The missing digit took the first two knuckles with it, but there’s enough left to easily interface with this creation. It’s a mechanically clever assembly that moves as you would expect the original to. See for yourself after the break. It seem the maker intended to mold silicone around the structure but never got around to posting an update video.

On the left we have a chinese man who lost his arms while fishing. It seems they were using homemade bombs instead of nets and one went off prematurely. Since then he’s constructed several different prosthetic arms, each with its own special purpose. This one has a saw connected to it but these two write ups on the man show images of him using a fork and wielding a hammer.

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A Laser Audio Transmitter

August 31, 2012 by 38 Comments

Here’s a way of transmitting audio that makes it virtually impossible for someone else to listen in. Instead of sending radio waves bouncing all over creation, this uses the focused light of a laser to transmit audio. In the image above you can see the silver cylinder which houses the laser diode. It is focusing the beam on a light dependent resistor to the right which looks almost like a red LED due to the intensity of the light.

The simplicity of this circuit is fascinating. On the receiving end there is no more than the LDR, a 1.5V power source, and a headphone jack. The transmitter is not much more complicated than that. It includes an audio output transformer which boosts the resistance of the audio signal. This increase in resistance ensures that the laser diode modulates enough to affect the LDR on the receiving end. The transmitter uses a 3.3V supply. Check out the video after the break to hear the high quality of audio coming through the setup.

Once you’re done playing around with the transmitter you might try turning the laser into a remote control for your stereo.

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Propeller Turned Into Chiptune Player With A Software SID

August 31, 2012 by 10 Comments

If there wasn’t reason enough to love the Parallax Propeller, now you can listen to chiptunes with your own pocket SID audio player.

This chiptune audio player uses the very unusual and very cool eight-core Parallax Propeller microcontroller. After soldering a few caps and resistors to a Propeller dev board to allow for audio out, the only thing necessary to play SID music files is a bit of code and an SD card breakout.

The key piece of code for this build would be the SIDcog object written by [Johannes Ahlebrand] this piece of code turns one of the eight cores in the Propeller into a virtual version of the classic Commodore 64 sound chip.

Since the SIDcog object only takes up one core on the eight core Propeller, it could be possible to turn this SID player into an all-inclusive chiptune audio source; the addition of an Atari POKEY or FM synthesis cog would allow for just about any conceivable chiptune sound to be carried around in a pocket.

No Hackaday post about chiptunes or SIDs would be complete without an audio demo, so you can check out the Propeller-powered SID after the break.

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The Simulacrum, An Innovative Solution To Walking In Virtual Reality

August 31, 2012 by 12 Comments

If you’ve been following along with immersive gaming, even casually, you’ve probably considered the difficulty in trying to do a comfortable and believable “walk” in a game. The first thing that usually pops into peoples minds are Omni Directional Treadmills, or ODTs. There are many problems with these, one of the biggest simply being cost. They’re very expensive.

[Zalo] at the MTBS3d forums has been working on his own very cost effective solution called the “Simulacrum”. He has built this for under $100 and it allows for a walking motion to be translated into the game. As you can see in the video below it works fairly well, even when one is out of commission for repairs (hence the limp).

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Raspberry Pi Synth Gives A Softsynth Dedicated Hardware

August 31, 2012 by 6 Comments

For all the musicians out there, here’s a great use for your Raspberry Pi. All the features you would expect from a nice analog synth are implemented in a Raspberry Pi-based polysynth – dual oscillators, LFOs, and phasers – and it looks like there will be a few more features added before the Raspi synth is released.

Even though the ‘synthesis’ part of the Raspi synth already sounds wonderful, getting MIDI on the Rasberry Pi leaves much to be desired. The creator of the Raspi synth thought about using the GPIO pins as a MIDI interface, but because the GPIO pins cannot run natively at 31250 bps (the MIDI spec), the Raspberry Pi has to waste most of its CPU cycles just listening for MIDI traffic.

Right now the Raspberry Pi synth is controlled by a USB-connected MIDI interface, and as you can hear after the break, sounds wonderful. We can’t wait to hear what this synth will be able to do in a few months’ time.

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Dual Core Arduino For More Pins

August 31, 2012 by 41 Comments

There are easy ways of getting more I/O pins for any project; shift registers, I2C expanders, or ADCs will give you plenty of pins for whatever project you have in mind. All these require extra components, though. Enter the ExtraCore library for Arduino, a software library that turns two or more Arduinos into a multi-core microcontroller with more pins than you’ll ever need.

The ExtraCore library comes from [Dustin Andrews], and allows anyone to control the input and output pins of two Arduinos with the same ease as a single Arduino.

The hardware setup is fairly simple – just connect A4, A5, power, and ground on both Arduinos together. After installing the ‘client’ sketch on the second Arduino, you can modify the ‘manager’ sketch to suit whatever project you’re building. From there you’ve nearly doubled the number of Arduino pins your project can control.

It may not be the most practical use of two Arduinos, but it’s certainly impressive. You can pick up [Dustin]’s code over on GitHub.

Doubling Down On Motor Drivers

August 30, 2012 by 31 Comments

Motor driver chip too weak for your needs? Just use two of them. That’s the advice which [Starlino] gives. He stacks motor driver chips to product move powerful controllers.

When stacked as shown, the driver combos should be able to drive at 4A. This is partly because he ganged together the outputs in pairs, and also because of the stacking. That’s a lot of juice, but [Starlino] documented his testing stage which shows that they’re up to it. It’s a bit hard to see from this angle, but he is using a serpentine heat sink. It snakes its way between the stack of chips, then over the top chip before folding back and spreading its wings. The motors he’s using have a stall current of 3.7A, and he included resettable fuses graded at a 2A hold current. He’ll be glad to have that extra protection is something goes wrong with the drivers.

[Thanks Roger]