Hackaday Links: October 11, 2015

October 11, 2015 by 13 Comments

[Kratz] just turned into a rock hound and has a bunch of rocks from Montana that need tumbling. This requires a rock tumbler, and why build a rock tumbler when you can just rip apart an old inkjet printer? It’s one of those builds that document themselves, with the only other necessary parts being a Pizza Hut thermos from the 80s and a bunch of grit.

Boot a Raspberry Pi from a USB stick. You can’t actually do that. On every Raspberry Pi, there needs to be a boot partition on the SD card. However, there’s no limitation on where the OS resides,  and [Jonathan] has all the steps to replicate this build spelled out.

Some guys in Norway built a 3D printer controller based on the BeagleBone. The Replicape is now in its second hardware revision, and they’re doing some interesting things this time around. The stepper drivers are the ‘quiet’ Trinamic chips, and there’s support for inductive sensors, more fans, and servo control.

Looking for one of those ‘router chipsets on a single board’? Here you go. It’s the NixCoreX1, and it’s pretty much a small WiFi router on a single board.

[Mowry] designed a synthesizer. This synth has four-voice polyphony, 12 waveforms, ADSR envelopes, a rudimentary sequencer, and fits inside an Altoids tin. The software is based on The Synth, but [Mowry] did come up with a pretty cool project here.

Video From Audio And Pure Data

October 11, 2015 by 12 Comments

Although graphical programming languages have been around for ages, they haven’t really seen much use outside of an educational setting. One of the few counterexamples of this is Pure Data, and Max MSP, visual programming languages that make music and video development as easy as dropping a few boxes down and drawing lines between them.

A few years ago, [Thomas] and [Danny] developed a very cool Pure Data audio-visual presentation. The program they developed only generated graphics, but though clever coding they were able to generate a few audio signals from whatever video was coming out of their computer. The project is called TVestroy, and it’s one of the coolest audio-visual presentations you’ll ever see.

The entire program is presented on three large screens and nine CRT televisions. With some extremely clever code and a black box of electronics, the video becomes the audio. Check it out below.

Although this is a relatively old build, [Thomas] thought it would be a good idea to revisit the project now. He’s open sourced most of the Pure Data files, and everything can be downloaded on the project page.

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Amazon Giving Out (Sort Of) Hackable Amazon Dash Button

October 11, 2015 by 49 Comments

We’ve seen some interesting hacks of the Amazon Dash buttons, a neat device where you press a button and it orders a product from Amazon for you. Now, [Amazon] themselves are getting into the hacking fun with the AWS IoT Button. This is a Dash button that Amazon is giving out at events to promote their new Amazon Web Services (AWS) Internet of Things (IoT) service.

As part of their efforts to take over the world, the AWS IoT service allows you to create button-based services like ordering pizza or starting Netflix, but without running your own server. Instead, Amazon handles all of the hard stuff behind the scenes on their Lambda engine, which receives the small bit of JSON that the button sends and runs a Lambda function that orders pizza, kicks off Netflix, then starts World War III. Amazon provides sample actions for things like launching the missiles sending a text message over Twilio and writing to a database. Amazon isn’t selling these buttons: they only seem to be available as swag at events. Make a loud enough noise in the comments section and maybe they’ll allocate some for the Hackaday community.

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Could You Repeat That?

October 11, 2015 by 12 Comments

Ever been out in a big field and need to tell something to Joe at the other end? If you’re lucky Sally is in between and you can shout to Sally to tell Joe your message. Maybe Joe shouts back to Sally in reply.

That’s how amateur radio repeaters work.

Friend of Hackaday [Kenneth Finnegan] got tired of explaining the details of repeaters so he put together a pair of repeater tutorial videos, the first of which is found after the break.

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Image source KV5R

The higher radio frequencies, say 50 MHz and above, typically only propagate within line of sight. Add in limited power and antennas from a hand-held, typically under 5 watts and the ubiquitous ‘rubber ducky’ antenna, and you cannot talk very far. Mobile rigs in vehicles with 50 watts and larger antennas do better but in reality they don’t help all that much.

What really makes an improvement is height to improve range. Height provides a longer line of sight with fewer obstructions. Hams created repeaters and put them on towers, buildings or hill tops to expand the radio horizon. The ultimate repeaters are space satellites. Can’t get much higher than that. A close second are balloons going to near space altitudes with repeaters which will provide multi-state coverage.

Besides providing height, a repeater will also have higher output power and much better antennas, especially important for receiving weak signals from distant handhelds. A signal comes in and is repeated back out on a slightly different frequency. All modern ham gear on these frequencies is setup to handle this offset frequency operation.

Whether hams came up with the idea is arguable, but they were certainly there during the early days.

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Anvil Firing: Awesome Or Reckless?

October 11, 2015 by 67 Comments

The English language needs a word for “awesome and dangerous simultaneously”.

We recently ran into the strange pastime of anvil shooting on YouTube (where else?). The idea is that you pack about a pound (!) of black powder between two anvils and light it up. The powder explodes, and the top anvil gets shot into the air. Hilarity ensues, if everyone’s far enough away and wearing hearing protection.

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See Who’s Calling With Caller Pi-D

October 11, 2015 by 13 Comments

One of the hardest things in life is watching your parents grow old. As their senses fail, the simplest things become difficult or even impossible for them to do.

[kjepper]’s mom is slowly losing her sight. As a result, it’s hard for her to see things like the readout on the caller ID. Sure, there are plenty of units and phones she could get that have text-to-speech capabilities, but the audio on those things is usually pretty garbled. And yes, a smartphone can natively display a picture of the person calling, but [kjepper]’s mom isn’t technologically savvy and doesn’t need everything else that comes with a smartphone. What she needs is a really simple interface which makes it clear who’s calling.

Initially, [kjepper] tried to capture the caller ID data using only a USB modem. But for whatever reason, it didn’t work until he added an FSK–DTMF converter between the modem and the Pi. He wrote some Node.js in order to communicate with the Pi and send the information to the screen, which can display up to four calls at once.  To make a mom-friendly interface, he stripped an old optical mouse down to the scroll wheel and encased it in wood. Mom can spin the wheel to wake the system up from standby, and click it to mark the calls as read. Now whenever Aunt Judy calls the landline, it’s immediately obvious that it’s her and not some telemarketer.

[via r/DIY]

Scratch Your Itch For 3D Modeling With BeetleBlocks

October 10, 2015 by 4 Comments

If you want to create a 3D model, you’ll probably either use a graphical CAD tool or a programming-based tool (like OpenSCAD). Although BeetleBlocks is graphical, it is more akin to OpenSCAD than a graphical CAD program. That’s because BeetleBlocks is–more or less–Scratch for 3D modeling.

Scratch is the graphical block-structured language developed by MIT for teaching kids to program. You may have seen Lego robots programmed with similar blocks as well as Android App Inventor. In this incarnation, the blocks control a virtual robot (the beetle) that can extrude a tube behind it as it moves. The beetle is reminiscent of the Logo turtle except the beetle moves in three dimensions. The system is actually closer to Snap, which is a reimplementation of Scratch that allows custom blocks.

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