Avoiding The Engineer-Saviour Trap

August 3, 2017 by 94 Comments

The random seaside holidays of Hackaday staffers rarely sow the seeds of our articles, but my most recent trip had something slightly unusual about it. I was spending a couple of days in a resort town on the Isle of Wight, just off the coast of Southern England, and my hotel was the local outpost of a huge chain that provides anonymous rooms for travelling salesmen and the like. I could probably find an identical place to lay my head anywhere in the world from Anchorage to Hobart and everywhere in between.

My room though was slightly different to the norm. By chance rather than necessity I’d been assigned one of the hotel’s accessible rooms, designed with people with disabilities in mind. And once I’d reached the limit of the free amusement that the digital TV channels of Southern England could provide, my attention turned to the room itself, eyeing up its slightly unfamiliar design features as an engineer.

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“The Alarm Clock Ate My Duvet Cover, That’s Why I’m Late!”

August 3, 2017 by 23 Comments

Some people just won’t wake up. Alarm clocks don’t cut it, flashing lights won’t work, loud music just becomes the soundtrack of an impenetrable dream. Maybe an alarm clock that rudely yanks the covers off the bed will do the trick.

Or not, but [1up Living] decided to give it a go. His mechanism is brutally simple — a large barrel under the foot of the bed around which the warm, cozy bedclothes can wind. An alarm clock is rigged with a switch on the bell to tell an Arduino to wind the drum and expose your sleeping form to the harsh, cold world. To be honest, the fact that this is powered by a 2000-lb winch that would have little trouble dismembering anyone who got caught up in the works is a bit scary. But we understand that the project is not meant to be a practical solution to oversleeping; if it were, [1up Living] might be better off using the winch to pull the bottom sheet to disgorge the sleeper from the bed entirely.

Something gentler to suit your oversleeping needs might be this Neopixel sunrise clock to coax you out of bed naturally.

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Motorized Turntable Created From TV Stand

August 3, 2017 by 2 Comments

[Robin Reiter] had a powered TV stand that only rotates around 20°, because who really needs their TV to rotate fully? He wanted to turn it into a motorized turntable for shooting videos, but first he had to hack it.

After opening it up [Robin] discovered that there was a surprising amount of electronics in the base. In addition to a DC motor, there was a potentiometer attached to a gear to give feedback, but it was set up for partial rotation so it had to be yanked out.

There was also a plastic gear with teeth around just part of the interior. [Robin] took a picture of the gear and dropped it into Fusion360, using the photo as a reference image while he re-created the gear. The new piece had teeth all around the periphery. After printing it out he glued it into the old gearbox, and now he had turned his TV stand into a motorized turntable.

If you’re looking for more along these lines, check out our posts on making parametric models in Fusion360 and turning a turntable into a waveform generator. Continue reading “Motorized Turntable Created From TV Stand” →

Cascade LNAs And Filters For Radioastronomy With An SDR

August 2, 2017 by 5 Comments

It may not be the radio station with all the hits and the best afternoon drive show, but 1420.4058 MHz is the most popular frequency in the universe. That’s the electromagnetic spectral line of hydrogen, and it’s the always on the air. But studying the H-line is a non-trivial task unless you know how to cascade low-noise amplifiers and filters to use an SDR for radio astronomy.

Because the universe is mostly made of hydrogen, H-line emissions are abundant, and their distribution can tell us a lot about the structure of galaxies. The 21-cm emission line is so characteristic and so prevalent that we used it as a unit of measurement on the plaques aboard the Pioneer probes as well as in the instructions for playing back the Voyager recordings. But listening in on 21-cm here on Earth requires a special setup, which [Adam (9A4QV)] describes in a detailed paper on the subject (PDF). [Adam] analyzes multiple configurations of LNAs and filters, both of which he sells, to determine the optimum front-end for 21-cm work. His analysis is a good primer on LNAs and explains why the front-end gear needs to be as close to the antenna as possible. Using his LNAs and filters and an SDR dongle, a reasonable 21-cm rig can be had for about $200 or so, less the antenna. He promises a follow-up paper on homebrew 21-cm antennas; we’ll be looking forward to that.

Not keen on the music of the spheres and prefer to listen to our own spacecraft instead? Then read up on the Deep Space Network and how you can snoop in.

Eradicating Mosquitoes From Your Backyard — With Seltzer?

August 2, 2017 by 81 Comments

Q: What do you call 8000 dead mosquitoes in a Mason jar?

A: A good start. And [Dan Rojas]’s low-tech mosquito trap accomplished the feat in two nights with nothing fancier than a fan and a bottle of seltzer.

We know what you’re thinking: Where’s the hack? Why not at least use a laser sentry gun to zap skeeters on the fly? We agree that [Dan]’s mosquito trap, consisting of a powerful fan to create suction and a piece of window screen to catch the hapless bloodsuckers, is decidedly low-tech. But you can’t argue with results. Unless he’s fudging the numbers, a half-full Mason jar of parasite cadavers is pretty impressive. And you have to love the simplicity of the attractant he’s using. Mosquitoes are attracted to the CO2 exhaled by tasty mammals, but rather than do something elaborate with a paintball gun cartridge or the like, [Dan] simply cracks a bottle of seltzer and lets it outgas. Dead simple, and wickedly effective. The trapped bugs quickly desiccate in the strong air stream, aided by a few spritzes of isopropyl alcohol before cleaning the screen, which leaves them safely edible to frogs and insects.

Simple, cheap, and effective. Sounds like a great hack to us. And it’s really just a brute-force implementation of this mosquito-killing billboard for areas prone to Zika.

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Raspberry Pi Tracks Office Happiness

August 2, 2017 by 16 Comments

It’s always great to see people who haven’t had the opportunity to work with hardware like the Raspberry Pi before come up with a great project and have fun putting it together.  [Katja]’s company has a two-day hackfest where employees can work on some cool non-work-related projects. [Katja]’s team decided to use a Raspberry Pi and some buttons and LEDs to create a ‘happiness tracker‘ for the company.

The resulting project is mounted near the entrance to the office and when they come in or leave, an employee can push one of four buttons to indicate their mood at the time, ‘bad,’ ‘not so good,’ ‘good’ or ‘super.’ The result is tracked and an overall impression of the office’s happiness is the result.

The project consists of the aforementioned Raspberry Pi, four push buttons, five LEDs that animate when a button is pressed and another LED that shows the system is currently up and working. When a user presses a button, the five LEDs animate in the shape of a check mark to show that the button press was successful. A Python script running at startup on the Pi takes care of detecting button pressing, lighting LEDs and sending a message to the server which monitors the level of happiness.

It’s a simple project, but that’s exactly what you need when you start with hardware you haven’t worked with before. It seems like [Katja]’s team had fun building the project and they hope that this can help gauge the overall wellbeing of the office. [Katja]’s blog post has an embedded video of the project in action. In the meantime, check out this bit of facial recognition software that determines how happy you are based on your smile, or this project that lets you know how happy your plant is.

Mini Tetris Game Packs A Tiny85

August 2, 2017 by 5 Comments

[dombeef] originally built pocketTETRIS as a Father’s Day gift for his Tetris-loving pops. However, having finished the project he’s decided to share it with the universe, and it’s looking rather sweet.

He made the game the smallest he could make, with size limitations imposed by a 0.96” OLED display, the coin-cell battery pack, and his desire for a durable 3D-printed case. It uses a ATtiny85 for the brains, mounted on a custom PCB that [dombeef] designed in KiCad. The Arduino code was modified from Andy Jackson’s ATtinyArcade code, giving it three-button capability instead of two. [dombeef] has details on the project page on Hackaday.io as well as 3D-design and PCB-design files on the project’s code repository on GitHub.

We’ve published a fair number of Tetris posts in the past, including skyscraper Tetris, playing Tetris on a soldering iron, and Tetris in 446 bytes. What’s the smallest Tetris you’ve seen?