The Four Thousand Dollar MP3 Player

[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.

Wooden Band Saw Fears Its Wood-Cutting Brethren

DIY Wooden Bandsaw

What is cooler than building a band saw out of wood? Building two, of course! And that is exactly what [Pekka] did. The first was a small bench top model while the second was a much larger version with the saw blade strung between big 13-3/4 inch wheels. For those who are unfamiliar with band saws, they are tools that have a long thin blade that is routed around rotating wheels. The wheels are spread apart to make the blade taut. Unlike the reciprocating action of a jigsaw, saws-all or scroll saw, the band saw blade continually rotates in one direction. These blades are typically thin making it easy to cut irregular and curved shapes.

The frame of [Pekka’s] larger machine is made from 35mm (~1-3/8″) plywood. This proved to be a sturdy frame material. The previously mentioned wheels were made by gluing pieces of oak together, mounting the assembly on a wood lathe and turning the outer diameter down to size. By using multiple piece of wood to construct the wheels allows the grain direction of each portion to be parallel with the blade. This method of construction ensures any expansion/contraction of the wood is uniform around the wheel. A strip of rubber around the blade’s outer diameter provides the friction required to prevent the blade from slipping.

[Pekka’s] friend was nice enough to turn the flanged axle shafts on his metal lathe. These shafts support the wooded wheels and are mounted in pillow block bearings. The upper pillow blocks are mounted to a sliding support that allows adjusting the tension of the saw blade. [Pekka] was not going to be satisfied with a one-speed band saw so he grabbed a motor he had kicking around that originally came from a wood lathe and already had 4 different sized pulleys mounted on the shaft.

This is a great project that shows what can be done with a little desire and ingenuity.

Home Made Miter Saw Is Not Completely Dangerous

Home Made Miter Saw

If the term ‘home made miter saw’ instantly instills frightening images of severed limbs into your head, you’re not alone. A quick internet search will yield some pretty hokey tool builds, we’ve even featured a few here on hackaday. This saw is different. [Pekka] made a pretty cool saw for cutting very accurate angles in wood.

This saw was purpose built with one goal in mind: cutting wood that will be glued together for use in segmented turning. Segmented turning is shaping a piece of wood stock that is composed of many different types of wood. This results in a very visually interesting product.

Home Made Miter SawMost of the saw is made from plywood. The hinge and supports for the arbor are beefy off-the-shelf pillow blocks. A 3-phase motor with speed control transmits power to the arbor via a belt. Belt tension is adjusted by sliding the motor further back along the motor mount base. [Pekka] took care so that the entire pivoting assembly was nearly balanced adding to the ease of use.Typical miter saws rotate the blade to achieve different angles of cuts. This design rotates the saw fence.

For safety there are a pair of polycarbonate blade guards and a micro switch on the handle that won’t let the saw start unless it is depressed. The micro switch has a secondary function also, when let go it applies an electronic brake to the motor so that the spinning blade does not touch the work piece when lifting the blade back up.

Rebuilding a Bridgeport mill

It looks like the Internet’s resident steampunker is moving up a century or two. [Jake Von Slatt] rebuilt the CNC portion of a Bridgeport Series II mill so it can interface with a computer. It’s a feat even more impressive than moving the mill into [Jake]’s garage.

The first step of the build was tearing out the BOSS 5 industrial microcomputer and replacing it with a Win XP laptop running ArtSoft’s Mach 3. This allows G-code to be displayed directly on the screen. The old power supply for the mill did give [Jake] a few problems. The Gecko stepper drivers that replace the old electronics couldn’t handle the voltage of the old power supply. That can be dealt with by opening the transformer and removing a few turns of wire.

[Jake] has been sending in a few of his hacks as of late, so it’s good to see Hack a Day has another fan, especially one of [Mr. Von Slatt]’s caliber. There is a problem with the mill modifications though – [Jake] hasn’t figured out how to program it. If any HaD readers would like to chime in on the best way to program G-code for the mill, feel free to leave a message in the comments.