This Billboard Kills Zika Mosquitoes

Once in a great while, effective advertising doesn’t require any human engagement at all. This billboard, designed and built by a pair of Brazilian ad agencies and set free under the Creative Commons license offers a reproducible solution for trapping Aedes Aegypti mosquitoes, the primary carrier of the Zika virus.

Click to embiggen.
Click to embiggen.

The design seems pretty simple, although the plans leave a bit of explanation to be desired. Inside the billboard are canisters of Lurex 3, a lactic acid-based mosquito attractant that is available pretty cheaply on Amazon. The lactic acid mimics the scent of human sweat and is released outward to distances up to 4km (2.5 miles) in a fine mist along with CO₂. Together, the Lurex and CO₂ act like a sweaty, mouth-breathing human beacon to lure mosquitoes into the billboard, where they become trapped and are doomed to die of dehydration.
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Hacklet 102 – Laundry Projects

Ah laundry day. The washing machine, the dryer, the ironing, and the folding. No one is a fan of doing laundry, but we (I hope) are all fans of having clean clothing. Hackers, makers, and engineers are always looking for ways to make a tedious task a bit easier, and laundry definitely is one of those tedious tasks. This week we’re checking out some of the best laundry projects on Hackaday.io!

laundrifyWe start with [Professor Fartsparkles] and Laundrify. Anyone who’s shared a washer and dryer with house or apartment mates will tell you how frustrating it can be. You bring your dirty laundry downstairs only to find the machines are in use. Wait too long, and someone has jumped in front of you. Laundrify fixes all that. Using a current sensor, Laundrify can tell if a machine is running. An ESP8266 monitors the current sensor and sends data up to the cloud – or in this case a Raspberry Pi. Users access this laundry as a service system by opening up a webpage on the Pi. The page includes icons showing the current status of each machine. If everything is in use, the users can join a queue to be notified when a machine is free.

 

borgmachineNext up is [Jose Ignacio Romero] with Borg Washing Machine. [Jose] came upon a washer that mechanically was perfect. Electrically was a different story. The biggest issue was the failing mechanical timer, which kept leaving him with soapy wet clothing. Washing machine timers boil down to mechanically timed multipole switches. They’re also expensive to replace. [Jose] did something better – he built an electronic controller to revitalize his washer. The processor is a PIC16F887. Most of the mains level switching is handled by relays. [Jose] programmed the new system using LDmicro, which is a ladder logic implementation for microcontrollers. For the uninitiated, ladder logic is a programming language often used on industrial Programmable Logic Controller (PLC) systems. The newly dubbed borg machine is now up and running better than ever.

 

hackitgreen

Next we have [Michiel Spithoven] with Hot fill washing machine. In North America, most washing machines connect to hot and cold water supplies. Hot water comes from the home’s water heater. This isn’t the case in The Netherlands, where machines are designed to use electricity to heat cold water. [Michiel] knew his home’s water heater was more efficient than the electric heater built into his machine. [Michiel]  hacked his machine green by building an automated mixing manifold using two solenoid valves and a bit of copper pipe. The valves are controlled by a PIC microprocessor which monitors the temperature of the water entering the machine. The PIC modulates the valves to keep the water at just the right temperature for [Michiel’s] selected cycle. [Michiel] has been tracking the efficiency of the new system, and already has saved him €97!

 

laundrespFinally we have [Mark Kuhlmann] with LaundrEsp. [Mark’s] washing machine has a nasty habit of going off-balance and shutting down. This leaves him with soggy clothing and lost time re-running the load. [Mark] wanted to fix the problem without directly modifying his machine, so he came up with LaundrEsp. When the machine is running normally, a “door locked” light is illuminated on the control panel. As soon as the washer shuts down – due to a normal cycle ending or a fault, the door unlocks and the light goes out. [Mark] taped a CdS light detecting resistor over the light and connected it to an ESP8266. A bit of programming with Thinger.io, and [Mark’s] machine now let’s him know when it needs attention.

If you want to see more laundry projects check out our brand new laundry project list! If I missed your project, don’t take me to the cleaners! Drop me a message on Hackaday.io, and I’ll have your project washed, folded, and added to the list in a jiffy. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

The Hacker’s Notebook: a Mission Log for Every Project

While “writing it down” might seem like common sense, it wasn’t always the case. From the times of Ancient Greece, Plato tells a story of a worried Egyptian King, who, upon witnessing the invention of writing, remarks,

“If men learn this, it will implant forgetfulness in their souls; they will cease to exercise memory because they rely on that which is written, calling things to remembrance no longer from within themselves, but by means of external marks. [1]”

To some, the notebook was a dangerous device, a thief that would rob us of our memories [2]. Fortunately, these days, there’s plenty of evidence from our Psych texts that say we humans are pretty shabby at keeping the facts straight. In fact, each time we recall a memory, we change it! Here lies the beauty of the notebook. Have an idea for a new project? Why not log it somewhere for future reference? With diligence, the notebook can become our own personal hub for spurring on new project ideas.

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5 Wide and Tall Monitors with Hacked Bezels for Wall of Awesome

If two is better than one, what about five? [Omnicrash] has posted a nice analysis of his monitor setup, which uses 5 portrait mounted monitors side-by-side. To minimize the bezel size between them, he removed the casing and built a custom stand that placed them all closely together for a surround viewing approach. He’s been using this setup for a couple of years and has posted a nice analysis of making it work for multiple purposes. On the upside, he says it is awesome for gaming and watching videos.

On the downside, NVidia’s drivers and multi-monitor setup are a pain, and some tasks just didn’t work with the bezels. He couldn’t, for instance, run a standard-sized remote desktop screen anywhere without having the bezel get in the way. So, with large, hi-res monitors now getting cheaper, would he do it again? “If I had to do it all over again nowadays however I’d probably just go with a single 34″ ultra-wide for about the same price..though I probably wouldn’t be able to help myself and would eventually be adding at least one on top and 2 in portrait on the side.”

Bone Up on Your Multiplication Skills

John Napier was a Scottish physicist, mathematician, and astronomer who usually gets the credit for inventing logarithms. But his contributions to simplifying mathematics and building shorthand solutions didn’t end there. In the course of performing the many calculations he needed to practice these subjects in the 1500s, Napier invented a kind of computing mechanism for multiplication. It’s a physical manifestation of an old system known as lattice multiplication or gelosia.

Lattice multiplication makes use of the multiplication table in order to multiply huge numbers together quickly and easily. It is thought to have originated in India and moved west into Europe. When the lattice method reached Italy, the Italians named it gelosia after the trellised window covering it resembled, which was commonly used to keep prying eyes away from one’s possessions and wife.

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The Stork Looks Different Than We Thought

What the Internet of Things really needs is more things, and the more ridiculous the better. At least, that’s the opinion of [Eric] who has created a tongue-in-cheek gadget to add to the growing list of connected devices. It’s a Bluetooth-enabled pregnancy test that automatically releases the results to the world. Feeling lucky?

The theory of operation is fairly straightforward. A Bluetooth low-energy module is integrated into the end of a digital pregnancy test. These tests have a set of photo detectors to read the chemical strip after the test is conducted. If the test is positive, the module sends a signal to a Raspberry Pi which tweets the results out for the world to see. It also has an option to send a text message to your mom right away!

[Eric]’s project to live-tweet a pregnancy test also resulted in a detailed teardown of a digital pregnancy test, so if you need any technical specifications for pregnancy tests (for whatever reason) his project site has a wealth of information. He does note that his device can be used on other similar devices with directly driven LCD screens, too. The fun doesn’t end there, though! Once the pregnancy is a little further along you’ll be able to get the baby on Twitter, too.

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Students Set Sights on DIY Eye Exams

What if you could give yourself a standard eye exam at home? That’s the idea behind [Joel, Margot, and Yuchen]’s final project for [Bruce Land]’s ECE 4760—simulating the standard Snellen eye chart that tests visual acuity from an actual or simulated distance of 20 feet.

This test is a bit different, though. Letters are presented one by one on a TFT display, and the user must identify each letter by speaking into a microphone. As long as the user guesses correctly, the system shows smaller and smaller letters until the size equivalent to the 20/20 line of the Snellen chart is reached.

Since the project relies on speech recognition, the group had to consider things like background noise and the differences in human voices. They use a bandpass filter to screen out frequencies that fall outside the human vocal range. In order to determine the letter spoken, the PIC32 collects the first 256 and last 256 samples, stores them in two arrays, and performs FFT on the first set. The second set of samples undergoe Mel transformation, which helps the PIC assess the sample logarithmically. Finally, the system determines whether it should show a new letter at the same size, a new letter at a smaller size, or end the exam.

While this is not meant to replace eye exams done by certified professionals, it is an interesting project that is true to the principles of the Snellen eye chart. The only thing that might make this better is an e-ink display to make the letters crisp. We’d like to see Snellen’s tumbling E chart implemented as well for children who don’t yet know the alphabet, although that would probably require a vastly different input method. Be sure to check out the demonstration video after the break.

Don’t know who [Bruce Land] is? Of course he’s an esteemed Senior Lecturer at Cornell University. But he’s also extremely active on Hackaday.io, has many great embedded engineering lectures you can watch free-of-charge, and every year we look forward to seeing the projects — like this one — dreamed and realized by his students. Do you have final projects of your own to show off? Don’t be shy about sending in a tip!

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