Simple Circuit Reminds You To Lock The Door As You Rush Out Of The House

October 11, 2011 by Mike Nathan 24 Comments

door_lock_minder

It seems that [pppd] is always rushing out of his apartment to catch the bus, and he finds himself frequently questioning whether or not he remembered to lock the door. He often doubles back to check, and while he has never actually forgotten to lock the door, he would rather not deal with the worry.

Since he finally had some free time on his hands, he decided to put together a simple device that would help end his worry once and for all. Using an ATtiny13, [pppd] designed a circuit that would detect when his door has been unlocked and opened, beeping every few seconds until the lock is reengaged. The circuit relies on a reed switch installed inside the door frame, which is tripped by the magnet he glued to his door’s deadbolt.

He says that the system works well so far, though he does have a few improvements in mind already.

Open-source Sprinkler Controller Keeps Your Lawn Looking Great

October 9, 2011 by Mike Nathan 16 Comments

open_source_sprinkler_controller

[Ray] wrote in to share a great project he just recently wrapped up, an open-source sprinkler valve controller. Built in collaboration with Wired Magazine’s editor-in-chief [Chris Anderson], the sprinkler controller is designed to replace the limited commercial sprinkler timers that typically come with a new home sprinkler setup.

Their system greatly expands on the idea of a standard sprinkler timer, adding Ethernet connectivity, web-based scheduling, and 8 separate controllable zones. At the heart of the controller is an ATmega328 running the Arduino bootloader, which means that the system is easily tweakable to fit your specific needs. The controller works off a standard 24V AC sprinkler transformer, which means that the controller can easily act as a drop-in replacement for your existing system.

The pair sells kits through the web site, but you can always simply download the schematics, PCB layout files, and BoM to build one yourself. Whichever path you choose, be sure to swing by [Ray’s] site and take a good look around – there is an incredibly detailed assembly and programming guide there that will be a great resource as you go along.

Continue reading to see a video of the sprinkler controller in action.

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Improving A Cheap Espresso Machine

October 9, 2011 by Brian Benchoff 15 Comments

For those of us that would like a good cup of coffee but don’t want to put up with the ‘burnt butt’ taste of Starbucks and don’t have a decent coffee shop nearby, we’ve had very few options. Most of us have been made to suffer with an el-cheapo espresso machine. [Joe] sent in a great build that improves these el-cheapo models and brings them up to the quality we would expect from their more expensive brethren.

For the best pull from an espresso machine, the great [Alton Brown] says 200° F water must be forced through the grind at around 10 ~~PSI~~ atm. [Joe]’s espresso machine can’t build up pressure because the heating element is only active when the lever is in the ‘brew’ or ‘froth’ position. To build up pressure in the water reservoir, [Joe] simply added a pressure gauge to the frothing attachment. When the gauge reads the necessary 10 atmospheres, just move the lever over to the ‘brew’ position and enjoy a nice cup of espresso.

[Joe] has already tested the pressure relief valve of his espresso machine. With the gauge in the way, [Joe] can’t make use of his frother, but a secondary valve could easily remedy that. [Joe] hasn’t published his espresso hack anywhere, but he did email us some pics of his build. We’ve embedded them as a slideshow after the break. Check out the pressure gauge on the frothing attachment and the pressure relief valve below.

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Effortlessly Troll Your Friends Each Time They Reach For A Snack

October 4, 2011 by Mike Nathan 11 Comments

trolling_your_friends_abusive_refrigerator

If you’re trying to lose some weight, [Grissini] has got the just the thing you need!

He recently tweaked his refrigerator to throw out insults each time its opened, though not for his own physical well-being. While we imagine that an abusive refrigerator would help curb your appetite for late night snacks, [Grissini] makes no bones about the fact that he simply wants to effortlessly and automatically troll his roommates.

The device is pretty simple, consisting of an Arduino and an Adafruit wave shield stuffed inside a styrofoam coffee cup. A photocell is used to detect when the refrigerator door has been opened, triggering the Arduino to play a sound bite from the on-board SD card. [Grissini] even spent a good chunk of time working with a text to speech engine in order to create a customized list of insults that point out his friends’ idiosyncrasies – what a guy!

Continue reading to see his abusive fridge in action, and be sure to check out his Instructableto learn how to make your own.

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How To Build Your Own Cat Door

October 2, 2011 by Mike Szczys 29 Comments

[Dino] continues his to satisfy his weekly hacking goal by building a cat door for his pets. He has a Habitat For Humanity resale store nearby that was doing a 50% off sale on doors. So he picked up a six-panel door and set to work.

The first step is drawing out the opening and cutting it with a jigsaw. Once he was done, there’s some reinforcement work to be done because this is a hollow-core door. Since he had already cut a bit of the bottom off of the door to fit his jamb opening, he had some wood stock that was already the right thickness. That bit was secured to the top and bottom of the opening with glue and some brads. The same was done on the sides with a different piece of scrap, then the door was hung in the opening to reach the point in the project seen above.

Here [Dino] prepares to add a flap to cover the opening. He used acrylic for the flap because it’s light-weight and clear. A piece of piano hinge makes it easy to swing in both directions. The final touch is a magnet which keeps the flap from swinging in the breeze using parts from a magnetic cabinet latch. No sooner does he have the flap in place than a brave kitty gives it a test run.

Hopefully he doesn’t have the kind of pests that caused other hackers to build facial recognition cat door locks.

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Repairing The Blue Canary In The Outlet By The Light Switch

September 30, 2011 by Mike Nathan 11 Comments

blue_canary_in_the_outlet_by_the_lightswitch

[Vince] and his wife are big fans of [They Might be Giants], so when they were perusing their local Target one evening and stumbled upon a blue canary nightlight, they bought it immediately. While the nightlight was easy for his toddler to use, the LEDs inside started to dim after about a month, and eventually they started flickering like mad as you can see in the video below. A battery swap didn’t remedy the problem, and instead of returning it, [Vince] decided to try fixing it himself.

After poring over the device’s simple circuit, he couldn’t figure out any reason why the nightlight would start behaving like it did. He did notice that a resistor was left out of the device, likely as a cost-cutting measure, so he added one in before replacing both of the nightlight’s LEDs.

With his simple tweak, the nightlight was better than new, saving him from what would likely be a string of annoying merchandise exchanges.

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Automated Humane Pest Control

September 24, 2011 by Mike Nathan 36 Comments

rat_trap_2000

[Tobie] seems to have a bit of a rat problem.

While most people would be inclined to simply buy the oversized Victor spring-loaded rat traps and call it a day, [Tobie] is a bit more humane. To help remedy his problem while also ensuring that no rats are harmed in the process, he built the Rat Trap 2000.

Self-described as completely over the top, the Rat Trap 2000 lures the rodents into its containment area with apples and corn, securing them inside using a servo-actuated trap door. The door is triggered by an Arduino that monitors the holding pen for movement using an IR sensor. All of the action is captured on video using the web cam on his Eee-PC, as you can see in the very short video below.

This certainly isn’t the most cost-efficient way to control your vermin problems, but if you’ve got some spare parts laying around, why not? It’s far more humane than some of the other rodent control solutions we have seen, and it sure beats living with rats!

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