Hackaday Links: April 20, 2014

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[Josh] hit the same issue we’ve faced before: cable modems don’t match a form factor and usually don’t make themselves easy to mount on something. We could complain about routers as well, but at least most of those have keyhole slots so you can hang them on some screws. Inspiration struck and he fabricated his own rack-mount adapter for it. Velcro holds it in place, with a cutout bezel to see the status lights and an added fan to keep things cool.

Here’s a pair of strange but possibly interesting ones that were sent in separately. The first is an analysis of how much energy short-run CNC prototyping consumes versus traditional manufacturing. The other is an article that [Liz] wrote about getting started with CNC mill bits. She says she compiled all that she learned as she was getting started in the field and wants to save others the effort.

This one goes back several years, but who doesn’t love to hear about a voice-controlled wheelchair?

So you can solder QFN parts but you can’t hammer a nail straight into a piece of wood? The answer, friend, is a laser guided hammer. Someone hire this [Andybot] person, because the solution to the problem shows the ability to out-think an interesting dilemma: how do you put a laser in a hammer head and still use it to hit things?

We’ve seen a lot of these long-range WiFi hacks over the years. This one is worth looking at because of the work done to create an outdoor mount that will stand the test of time.

And finally, we’re still really fond of this 2-bit paper processor that helps you wrap your brain around what’s going on with those silicon wafers that rule our everyday lives. [glomCo] liked it as well, and actually coded an emulator so that you can play with it without printing anything out on paper. We think it takes away some of the fun, but what an excellent programming exercise!

Laser Cutter Becomes An Etch A Sketch

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The mirror in a laser cutter moves along an X Y axis. An Etch A Sketch moves its stylus along an X Y axis. Honestly, this laser cutter with Etch A Sketch controls is so obvious, we’re shocked we haven’t seen it before.

The Etch A Sketch interface is extremely simple – just two rotary encoders attached to laser cut knobs set inside a small, laser cut frame. The lines from the encoders are connected to an Arduino Pro Mini that interfaces with the controller unit on the laser cutter, moving the steppers and turning on the laser only when the head is moving. There’s an additional safety that only turns on the laser when the lid is closed and the water pump is running.

The circuit is extremely simple, and with just a few connections, it’s possible to retrofit the Etch A Sketch controller to the laser cutter in just a few minutes.  Just the thing for a weekend hackerspace project.

 

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Etching Designs Into Denim With A Laser Cutter

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Finding new uses for your tools and equipment can be very exciting. [Foamy] wrote in to tell us about a blog post by [qbotics] that demonstrates etching designs into denim with a laser cutter. What a cool unexpected use for a laser cutter!

According to the Epilog laser cutter’s website, “we have engraved everything from denim to acrylic with fantastic results”. This inspired the author of “Science with denim” to try engraving jeans. After some experimentation,  [qbotics] found that setting the 75W laser cutter to 15% power at 100% speed worked best. The results are quite impressive; the engraved pattern looks like naturally faded jeans. Amazing.

In the past, we have seen lasers engrave everything from calculators to wood. We would be curious to see if some of the DIY laser cutters could engrave denim as well. Give it a try and tell us about it!

A 3-Axis Paper Cutting Mini Laser

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Laser are awesome, and so are projects that use lasers. A recent Instructable by [kokpat] gives an overview of how to create a fully functional laser paper cutter using CDROM stepper motors and an Arduino.

What is special about this build, is that it showcases how easy it can be to build a 3-axis mechanical system used for laser cutters, CNC machines, and 3D printers. Using a stepper stage that consist of a motor screw with a nut slider based carriage, the mechanical system can be put together quite easily and cost effectively. Luckily, from an electronics and software perspective, everything is quite standardized with the proliferation of the RepRap and similar machines. Simply pick any three stepper drivers, find the most pertinent firmware, and voilà! You’re done! Well, almost. Don’t forget a 100mW violet laser!

We have seen a ton of really cool laser cutters before, but this has to be one of the cheapest. See the laser cutter in action after the break.

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Homebrew Phase Laser Rangefinder

Just when you thought ARM micros couldn’t get any cooler, another project comes along to blow you away. [Ilia] created a phase laser rangefinder (.ru, Google translatitron) using nothing but a laser diode, a pair of magnifying glasses, a few components and an STM32F4 Discovery dev board.

The theory behind this build is using a laser’s phase to determine how far away an object is. By modulating the laser diode’s output at a few hundred Mhz, the reflection from the laser can be compared, giving a fairly reasonable estimate of how far away the target is. This method has a few drawbacks; once the reflection is more than 360 degrees out of phase, the distance ‘loops around’ to being right in front of the detector.

The laser diode used does not have any modulation, of course, but by using an STM32F4 ARM chip, [Ilia]was able to modulate the amplitude of the laser with the help of a driver board hacked out of a 74HC04 chip and a few resistors. Not ideal, but it works.

The receiver for the unit uses a photodiode feeding into the same microcontroller. With an impressive amount of DMA and PLL wizardry (the STM32F4 is really cool, you know), the phase of both the transmission and reflection can be compared, giving a distance measurement.

It’s all an impressive amount of work with a hacked together set of optics, a cheap dev board, and a few components just lying around. For any sort of application in a robot or sensor suite this project would fall apart. As a demonstration of the theory of phase laser rangefinding, though, its top notch.

You can check out a video of [Ilia]’s rangefinder below. Be sure to full screen it and check out the distance measurement on the LCD. It’s pretty impressive.

Thanks [Володимир] for the link.

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From Schematic To PCB In Four Hours

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Last super bowl Sunday, instead of checking the game, [Mattw] decided to extend a design and make a PCB of a trinket clone. [Mattw] altered a trinket clone design by [Morgan Penfield Redfield] to shrink it down, perforated the USB connector to allow for easy removal and put most of the parts on a single layer.

After finalizing the design, [Mattw] put it into the LPKF Protolaser S that Seattle’s Metrix Create Space has. For those of you who don’t know, the LPKF protolaser uses a laser to directly ablate off the copper from the boards.  This makes prototyping much faster without the need for a lot of nasty chemicals.

About six minutes in the Protolaser, some component placement by hand followed by a run through their reflow oven and [Mattw] had three boards ready to be tested. All told, about 4 hours from start to finish.

The end circuit looks great and the LPKF protolaser gives us a case of serious tool envy. If you’re like us and don’t have access to the fancy laser you might try our hand at this high-resolutino photo-etch process.

[via reddit]

Lazing With A Ruby

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[Ben Krasnow], builder of amazingly complex and technical devices, is finally starting work on his ruby laser. He’s been collecting parts for this project for the past few years, but only recently has he started recreating the first visible light laser.

While the design and manufacture of the first ruby laser was astonishingly complex, the basic idea behind it is pretty simple. [Ben]’s laser uses a synthetic ruby rhod with the ends ground optically flat. This rod is placed inside a flash tube. When the flash tube lights up, the rod absorbs the light and re-emits it as a coherent beam for several milliseconds. This beam bounces between two mirrors – one fully reflective and another partially reflective – and emits a constant stream of coherent photons. It’s tremendously more complex than simply connecting a laser diode to a power source, but replicating a build that graced the covers of Time and Newsweek only fifty years ago is pretty impressive

Right now, [Ben] has most of the mechanical and optical parts of his ruby laser on his workbench. The next step is constructing a huge capacitor bank to charge the flash tube every millisecond or so. What [Ben] will end up using his laser for remains up in the air, but if we come across some erbium or neodymium rods we’ll be sure to send them his way.

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