Ultimate Oscilloscope Hack – Quake In Realtime

December 29, 2014 by Matt Freund 48 Comments

[Pekka] set himself up with quite the challenge – use an oscilloscope screen to display Quake in realtime – could it even be done? Old analog scope screens are just monochromatic CRTs but they are designed to draw waveforms, not render graphics.

Over the years Hackaday has tracked the evolution of scope-as-display hacks: Pong, Tetris, vector display and pre-rendered videos. Nothing that pushed boundaries quite like this.

[Pekka]’s solution starts off the same as many others, put the scope in X-Y mode and splice up your headphone cable – easy. He then had to figure out some way to create an audio signal that corresponded to the desire image. The famous “Youscope” example demos this, but that demo is pre-rendered. [Pekka] wanted to play Quake in realtime on the scope itself, not just watch a recording.

With only so much bandwidth available using a soundcard, [Pekka] figured he could draw a maximum of about a thousand lines on screen at a time. The first headache was that all of his audio cards had low-pass filters on them. No way around it, he adjusted his ceiling accordingly. ASIO and PortAudio were his tools of choice to create the audio on the fly from a queue of XY lines given.

To tell his audio engine what lines to draw, he solicited Darkplaces – an open source Quake rendering engine – and had it strip polygons down to the bare minimum. Then he had to whip out the digital hedge trimmers and continue pruning. This writeup really cannot do justice to all the ingenious tricks used to shove the most useful data possible through a headphone jack. If this kind of thing interests you at all, do yourself a favor and check out his well-illustrated project log.

In the end [Pekka] was not entirely happy with the results. The result is playable, but only just barely. The laptop struggles to keep it simple enough, the soundcard struggles to add enough detail and the scope struggles to display it all quickly enough. At the very least it sets the bar extraordinarily high for anyone looking to one-up him using this method. There is only so much water that can be squeezed from a rock.

See the video below of [Pekka] playing the first level of Quake.

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Trinket EDC Contest Entry: Shorty

December 29, 2014 by Adam Fabio 9 Comments

Sometimes finding a short-circuit is easy, especially after the magic smoke has escaped. Finding a short on a newly etched or milled board though, can be a maddening task. Many of us have been there – wrestling with multimeter probes under a magnifier trying to find the offending bit of copper that is the source of all our problems. [Jaromir] designed Shorty to make this task a little bit easier.

Shorty is a short-circuit finder – but it’s not exactly like the one you would find on a typical multimeter. [Jaromir] used MCP6041 Op-Amp to detect resistances down to the order of tens of milliohms. Determining an exact resistance measurement at these levels would require a heck of a lot of calibration. When looking for a short though, [Jaromir] is only concerned with the relative value – is he getting closer to or further away from the short. He determines this by sound. The Op-Amp output is sent to the Pro Trinket’s ADC input. The trinket drives a speaker with lower or higher tones based upon the ADC voltage. Much like the childhood game of “hot and cold”, Shorty will direct you right to your short!

There’s still time to enter the Trinket Everyday Carry Contest. The main contest runs until January 2, but we’re having random drawings every week! Don’t forget to write a project log before the next drawing at 9pm EST on Tuesday, December 30th. You and all of the other entrants have a chance to win a Teensy 3.1 from The Hackaday Store!

DIY Super Accessory For Your Dremel

December 29, 2014 by Rich Bremer 50 Comments

Little jobs require little tools and you can’t get much more littler than a Dremel. For his tiny tasks, [sdudley] has built a Dremel-powered base station that features a table saw, drum sander and router table. Overall, it is about one cubic foot in size and is almost entirely made from ‘1 by’ dimensional lumber. The Dremel power plant was actually used to make the base, specifically slowly removing material at the clamping points that hold the rotary tool secure to the base. The Dremel is held in an upright position and pokes out through the center of the table for both the drum sander and router configurations. To use this as a table saw, the Dremel is mounted almost horizontally on the base. A Mini Saw attachment has to be purchased for the table saw configuration but it does a great job at holding a vertically spinning saw blade.

After the break there’s a nice video of this tool’s use and assembly (it’s even worth watching just for the musical accompaniment that takes you on a wild ride through several genres of music). For those who want to make one for themselves, [sdudley] has made his part templates and assembly guide available in PDF format on his Instructables page. If you’re looking for something a little larger, check out this circular saw converted to a table saw.

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DIY Thickness Sander Is Good Enough For A Guitar Shop

December 27, 2014 by Rich Bremer 27 Comments

[Pat] is a luthier and general guy that likes to build stuff. In order to get his guitars to come out the best they can, he needed a thickness sander. For those who don’t know, thickness sander is a machine that will sand off a small amount of material from the surface of a large wood panel. There are certainly commercially available thickness sanders but [Pat] thought that they were simple enough machines so he decided to give a go at making one himself.

Since [Pat] already had access to a pretty nice wood shop, it only made sense to build the thickness sander primarily out of wood. The frame is made from standard 2×4’s. The drum is made from many disks of MDF mounted on a shaft and spun by an AC motor. You might imagine that a bunch of MDF disks mounted on a shaft would not result in a very cylindrical shape and that is exactly what happened here. So before applying the sand paper to the drum, course sandpaper was applied to a sheet of plywood and used to sand the drum round. It’s a super simple technique that resulted in a true-spinning drum. Afterward, velcro is attached to the drum and velcro-backed sandpaper is wrapped around the drum. This allows quick and effortless changing of sand paper.

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Hanging Monitors Keeps Your Desk Slightly Less Messy

December 27, 2014 by Brian Benchoff 33 Comments

[Gertlex] – like just about everyone reading this, I’m sure – has a messy desk with monitors, keyboards, mice, several other input devices, tablets, and a laptop. He wanted a system that would reduce the wire clutter on his desk and after thinking a bit came up with a really cool solution for arranging his monitors. He’s hanging the monitors from a shelf above his desk using nothing but some aluminum and a few 3D printed brackets.

The main structure is a shelf of ‘bridge’ above his desk, made from 3/4″ ply. The inventive bit of this build is the two 1″ square aluminum tubes spanning the width of this shelf. From these, a few bits of aluminum angle pieces slide along the 1″ rails. a mount holds a 1″ round pipe to these supports, and a VESA mount is clamped to the pipe. There’s an imgur album that goes through the entire design. It’s certainly an improvement over the earlier battlestation, and the wiring loom cleans everything up nice and tidy.

[Gertlex]’s new system of hanging monitors is great, but this simple puts some even cooler builds on the table. The sliding system is great, but by putting one monitor on its own carriage, you could have an infinitely reconfigurable monitor setup. Some proper bearings, 3D printed VESA mounts, and maybe even a few stepper motors would make a build like this the coolest battlestation rig since the great ‘capacitor plague and I have a soldering iron so free monitors’ spectacular of 2005.

Dremel Powered Duplicating Carving Machine

December 26, 2014 by Rich Bremer 19 Comments

[Adran] wanted to be able to accurately cut out a bunch of the same parts out of wood but didn’t have the cash to spend on buying or building an automated CNC machine. After thinking about it for a while he decided to build a mechanical device that will allow him to duplicate objects by tracing them in 3 dimensions. This type of duplicator uses a stylus to trace over the surface of an object while the cutting tool is also moved over a piece of raw material, cutting as it goes. The end result is a newly carved object that is the same shape as the original. The idea is like a pantograph that works in 3 dimensions.

The wood frame is constructed to move freely front to back and left to right. To control the height of the cutting tool, in this case a Dremel, the frame pivots up and down and the X-axis rail. A screw driver is mounted off the side of the Dremel that acts as a stylus. It is mounted in the same orientation as the Dremel bit and is constrained such that it and the Dremel move in the same direction and amount at all times. When the tip of the screwdriver is traced over a 3D part, the Dremel moves the exact same amount carving a part out of a block of material.

Although the machine works, [Adran] admits there is some room for improvement. The left to right motion is a little choppy as the wood frame is riding directly on steel rails. He plans on adding linear bearings for the next revision to smooth things out.

The Four Thousand Dollar MP3 Player

December 26, 2014 by Brian Benchoff 64 Comments

[Pat]’s friend got a Pono for Christmas, a digital audio player that prides itself on having the highest fidelity of any music player. It’s a digital audio device designed in hand with [Neil Young], a device that had a six million dollar Kickstarter, and is probably the highest-spec audio device that will be released for the foreseeable future.

The Pono is an interesting device. Where CDs have 16-bit, 44.1 kHz audio, the Pono can play modern lossless formats – up to 24-bit, 192 kHz audio. There will undoubtedly be audiophiles arguing over the merits of higher sampling rates and more bits, but there is one way to make all those arguments moot: building an MP3 player out of an oscilloscope.

Digital audio players are limited by the consumer market; there’s no economical way to put gigasamples per second into a device that will ultimately sell for a few thousand dollars. Oscilloscopes are not built for the consumer market, though, and the ADCs and DACs in a medium-range scope will always be above what a simple audio player can manage.

[Pat] figured the Tektronicx MDO3000 series scope sitting on his bench would be a great way to capture and play music and extremely high bit rates. He recorded a song to memory at a ‘lazy’ 1 Megasample per second through analog channel one. From there, a press of the button made this sample ready for playback (into a cheap, battery-powered speaker, of course).

Of course this entire experiment means nothing. the FLAC format can only handle a sampling rate of up to 655 kilosamples per second. While digital audio formats could theoretically record up to 2.5 Gigasamples per second, the question of ‘why’ would inevitably enter into the minds of audio engineers and anyone with an ounce of sense. Short of recording music from the master tapes or another analog source directly into an oscilloscope, there’s no way to obtain music at this high of a bit rate. It’s just a dumb demonstration, but it is the most expensive MP3 player you can buy.