Humidity Activated Bathroom Fan

bathroom humidifier

[Andrea] recently moved into an apartment with a few of his friends. Unfortunately the bathroom lacks one of the most important things — A fan. Or at least a window!

Using the case of an air freshener, a simple DHT11 Humidity/Temperature sensor, an LCD, a 12V fan, and ATmel328 microcontroller, he created this handy gadget.

When the humidity in the bathroom passes the 50% threshold, an LED flashes to prompt the user to open the door. After a short delay, one of the transistors flips causing the moist air to circulate out of the room.

We’re surprised the little 12V fan is powerful enough to clear the room, but apparently it helps a lot and can clear the room in less than 20 minutes.

To see it in action, stick around after the break.

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SSTV Beacon Based On A Raspberry Pi

The Budapest hackerspace did some joint work with a local ham radio club and created an SSTV beacon housed inside a CCTV case that takes an image of its environment and transmits it using slow-scan television over ham bands.

As the title says, the build uses a Raspberry Pi to process the image taken from its camera and then transmits it over the air using a Ricofunk UHF transceiver with a main frequency of 433.425MHz. On the software side, PySSTV is used to convert images to frequency/time tuples, UNIXSSTV then creates the actual audio file and finally sox plays it. To avoid screwing up the Raspberry SD card, every part of the filsystem is either mounted in read-only mode (things like /home and /usr) or uses a ramdisk (things like /tmp and logs).

The plans, schematics and source code are available, so they hope that other hackerspaces will join the ranks!

Pepper’s Ghost – Halloween Ghosting

Peppers Ghost is a classic technique for making ghosts appear in pictures, video, and even in front of live audiences. In this week’s Halloween themed Instructable, learn how to recreate the effect at home.

It’s really quite simple. By positioning a clear piece of lexan at a 45 degree angle to your “ghost” object, and having the audience (or camera) looking at the lexan at the opposite 45 degree angle, you can produce a very simple ghost effect. This is a great trick for producing some scary ghosts in your haunted house.

But wait. Isn’t this a bit too simple? This is Hack a Day isn’t it? How about making a real moving hologram, isn’t that a bit more of our speed?

Well, this is the exact same technique that is used to make real holograms — just replace that object with a projected image or video! We’ve covered it a couple of times before, explaining the Tupac hologram, and showing off a cool leap motion controlled globe hologram.

Our challenge to you is to make a moving hologram Halloween decoration. After all, you can get pico projectors for less than $100 these days, so why not give it a try? There’s a few more ideas and techniques for positioning the lexan in the video after the break.

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DIY CD Autoloader

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From the German Hackerspace Ffm comes this extremely robust DIY disc autoloader (translated)! We hope your German isn’t too rusty…

[David] was tired of copying his CD collection by hand, so he set out to make an open source DIY disc autoloader. His first prototype was this one, which we have to admit gets style points (it made use of a gaming PC tower as the enclosure).

One of his goals for the project was simplicity, and with that in mind he created a driverless solution, using mechanical actuators to do everything — all you have to do is plug in your computer to the drive. It makes use of a gripper taken from a notebook optical drive and a series of counterweights to pick up and deposit the disks. The frame is made of aluminum extrusion and the major functional brackets are all 3D printed.

To see it in action, stick around after the break. We personally like the use of the counterweight pulley in the back!

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A Laminar Flow Nozzle

A few years ago Hackaday featured a laminar project which recently inspired [Kurt] to create his own. His goal is to create a computer controlled night time light show synchronized with music.

The laminar nozzle shown in the picture above is built with 800 drinking straws all placed in parallel inside a 4″ PVC pipe. The water input is a 3/4″ garden hose adapter, perpendicular to the flow of the output nozzle. The built therefore consists of cleaning sponges placed near the water inlet, followed by the straws and an inch gap to the exit nozzle. To get a nice flow, the edge of the exit nozzle must be as sharp as possible. [Kurt] purchased a brass pipe end cap, drilled a hole in it and sanded it to create a sharp inner edge. For the lights, he used 2 high power LEDs mounted with 3mm fiber optic cables, driven at around 5 Watts.

The link to the article that inspired Kurt can be found here.

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Self-stabilizing Spoon For People With Parkinson’s

Here’s a really cool story we just picked up — a gyroscopic steady-spoon, designed for people with Parkinson’s disease or other tremor inducing ailments.

The creator [Anupam Pathak] is close to people who suffer from tremors, and seeing the problem up close and personal, he set out to create a solution. He started the company called Liftware, and has so far released the Lift spoon. It features an embedded microchip, sensors and a few small motors. It’s capable of stabilizing tremors of up to 2 inches, which in several medical studies resulted in approximately a 70% tremor cancellation rate!

If you haven’t seen the effects of Parkinson’s on anyone, watch the video after the break. You’ll have your heart strings pulled a bit seeing how difficult eating can be, but then amazed at the ingenuity and effectiveness of the Lift Spoon. We can only imagine the paradigm shift this will be for people suffering from tremors.

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JJ Dasher: The Tinkerer (Documentary)

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This isn’t our usual faire, it’s a really cool documentary on a hacker. [JJ Dasher] is a tinkerer from Taylorsville, Utah — and this is his story.

Like many mechanical hackers, he got his start taking apart engines with his dad who owned a motorcycle repair shop at the time. The cover photo above is of his micro-bike project, which can get him going quite fast! He’s also built quite a few tesla coils, and loves picking up things from thrift stores to hack. He’s got a kid now which takes up a lot of his time, but he jokes that his son is just his next big project waiting to be finished.

We’ve actually featured [JJ’s] projects quite a few times before. He brought us the Doombox (handheld Doom-only computer), the awesome brute force GPS PIN cracker, and in the spirit of halloween one of our favorites: a tesla coil that delivers shocking candy!

Stick around after the break to watch the well-filmed documentary — don’t worry, it’s only 8 minutes long!

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