RADAR Controlled Speakers

[Scott] had a simple problem – he was tired of leaning over his work bench to change the volume on his speakers. He desired a system that would readily allow him to switch the speakers on and off from a more comfortable distance. Not one to settle for the more conventional solutions available, [Scott] whipped up a RADAR-activated switch for his speaker system.

The build relies on a surprisingly cost-effective RADAR module available off the shelf, running in the 5.8GHz spectrum. At under $10, it’s no big deal to throw one of these into a project that requires some basic distance sensing. [Scott] decided to keep things simple – instead of going with a full-fat microcontroller to control the speakers, a 74HC590 IC was used to create a latch. Each time the RADAR module senses an object in close proximity, it toggles the state of the latch. The latch then controls a transistor that switches the power for the speakers.

Overall it’s a build that combines a modern integrated RADAR module with some very simple control logic to create a functional build. Of course, there’s so much more you can do with some 74-series logic. Video after the break.

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Hackaday Prize Entry: Wireless Weather Station Protects Crops From Frost

It seems like you hear it every year — a late or early frost threatens some crop or another, forcing farmers to take drastic action to avoid financial ruin. But even when the weather cooperates on a large scale, microclimates can still cause big problems in small enough areas to go unnoticed until after the damage is done.

As always, better data can lead to better decisions, and increased granularity of environmental data could do wonders for certain kinds of agriculture. Enter SLoRa, a wireless weather station for agriculture. Aimed at providing a network of cheap, low-power temperature sensors, [Dorijan]’s proposed system would allow farmers to take active measures to protect their trees from frosts — smudge pots to heat the nascent fruit, sprinklers to apply a protective layer of ice, or even hovering helicopters to move massive amounts of warmer air into cold spots. With a solar powered sensor array and a LoRa link to a hilltop gateway, each SLoRa sensor deployed will be one more data point a farmer can use to determine where to deploy his or her limited resources.

Need to get up to speed on LoRa? You could do worse than learning how to listen in on LoRa signals with an SDR dongle.

Sort Out Chemical Storage For Your Shop

There is one constant in the world of hardware hacker’s workshops, be they a private workshop in your garage or a public hackspace, and it goes something like this:

Everybody’s a safety expert in whatever it is they are working with, right up until the accident.

In other words, it is very tempting to harbour a cavalier attitude to something that either you are familiar with or the hazards of which you do not understand, and this breeds an environment in which mishaps become a distinct possibility.

As hardware people, we are familiar with basic tool safety or electrical safety. The chances are that we’ve had it drummed into us at some time in our growing up, by a lab supervisor, a workshop teacher, or a parent. That you as readers and I as writer have survived this long is testament enough to the success of that education. But what about those areas in which we may not have received such an education, those things which we either encounter rarely or seem harmless enough that their safety needn’t be our concern? Chemicals, for example: everything from glue through solvents and soldering consumables to PCB chemicals and even paint. It all seems safe enough, what could possibly go wrong? The answer to that question is probably something most of us would prefer never to find out, so it’s worth looking in to how a well-run workshop can manage its chemicals in as safe a manner as possible.

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PCB Art Becomes Lapel Pins

We’re now living in the golden age of PCB art. Over the last year or so, the community has learned to manipulate silk screen, copper, and solder mask layers into amazing pieces of craftsmanship. These boards are putting the ‘A’ in STEAM, and now we have fiberglass replacements for enamel lapel pins.

[jglim] didn’t have much experience with fabric, but a PCB lapel pin was something that seemed like it should work. There are really only three parts to a lapel pin — the small ornamental pin itself, a solderable spike somehow attached to the pin (usually by soldering), and a clasp that holds the pin steadfastly to a lapel. The spike and clasp assembly were easily sourced on AliExpress, with one hundred clasps available for seven dollerydoos.  Attaching the spike to the PCB was as simple as adding a circular copper pad on the obverse side, applying some solder, and the liberal application of toaster ovens.

The design of the pin was based on the HTML5 logo, with the actual art done in Photoshop using a palette picked from OSHPark’s preview colors. The four colors used in this design are bare copper, a light purple for mask over copper, a darker purple for mask without copper, and a pale yellow for exposed FR4. This design was imported into KiCad with the Bitmap2Component tool.

The assembly of these lapel pins went very easily, and the finished product looks great. There’s a lot you can do with the standard OSHPark color stackup like making money of me, and this is a great example of exactly how much you can do with PCB art.

Linux-Fu: Running Commands

One of the things that makes Linux and Unix-like systems both powerful and frustrating is that there are many ways to accomplish any particular goal. Take something simple like running a bunch of commands in sequence as an example. The obvious way is to write a shell script which offers a tremendous amount of flexibility. But what if you just want some set of commands to run? It sounds simple, but there are a lot of ways to issue a sequence of commands ranging from just typing them in, to scheduling them, to monitoring them the way a mainframe computer might monitor batch jobs.

Let’s jump in and take a look at a few ways you can execute sequences from bash (and many other Linux shells). This is cover the cron and at commands along with a batch processing system called task spooler. Like most things in Linux, this isn’t even close to a complete list, but it should give you some ideas on ways to control sequences of execution.

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DEF CON Badgelife: The Puffy That Runs Linux

DEF CON is canceled again this year, and this time that statement is at least partially true. There will be no special official badges this year. There is no challenge or mystery embedded in the official DC badge. This is the year that unofficial badges from villages and random attendees finally supersedes the official offering. This is badgelife, and for the next few weeks, we’re going to be taking a look at some of the unofficial badges of DEF CON.

The idea for [dorkengine]’s Puffy badge began last year with the so-called Bender badges from AND!XOR.  Chalk this up to a story that ends with, ‘but you had to have been there’, but the Bender badges were wildly popular, sold like hotcakes, and were an astonishing success of independent badge craft at DC. [dorkengine] decided to get in on the action and build his own badge for DC 25.

The design of the Puffy badges is based on a highly stylized rendering of the OpenBSD logo and mascot. Why a pufferfish with Kardashian lips? [dorkengine] has a bunch of boxes in a closet running OpenBSD, and that’s a good enough reason for us.

An electronic badge must do something, and the feature list [dorkengine] came up with included some sort of wireless connectivity, hackability, a serial console, blinkenlights, and some sort of *nix-ish OS. OpenBSD didn’t make the cut, but [dorkengine] eventually stumbled upon the VoCore2, a tiny System on Module that runs Linux, has WiFi and a few GPIOs, and is barely an inch on a side.

After getting a good deal on a large order of VoCores, [dorkengine] started on the PCB. The circuit was simple enough with just a VoCore attached to a USB port, power adapter, and a few LEDs. The Puffy rendering translated beautifully into soldermask and silkscreen, and after a prototype from ITEAD Studio, [dorkengine] had 40 PCBs that worked perfectly.

So, what is [dorkengine] going to do with a box full of Puffy badges? He’ll be selling them for $40 around the con. That’s surprisingly inexpensive for a large PCB soldered to a $17 SoC. If you want to get your grubby mitts on one, you could email him or ping him on Twitter. Of course, if you want to make your own, [dorkengine] has the KiCad files and software available, but at this point, you’re looking at a very fast turnaround for a board house.

Tetris On A Soldering Iron

Our commenteers have all said good things about the open-source TS100 soldering iron pencil: things like “it solders well”. But we’ve all got soldering irons that solder well. What possible extra value does having open-source firmware on a soldering iron bring? [Joric] answered that question for us — it can play Tetris. (Video embedded below.)

While that’s cool and all, it wasn’t until we were reading through the README over at GitHub that the funniest part of this hack hit us. Every time you lose a game, the iron tip temperature increases by 10 degrees. Tetris for masochists? The makings of some horrible bar bets? We’re just glad that it’s open-source, because we’re not that good and it would get too hot to handle fast.

We haven’t tried out a TS100 yet, but this hack is almost pushing us to impulse purchase. There are alternative versions of the firmware if you just don’t like the font, for instance. And now, Tetris. Will this become the hot new gaming platform that you’ve been waiting for? Let us know in the comments.

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